Vox AC’s are the Goldie Locks of amps: not too sterile clean, not too much distorted roar. They’re “just right.” The red tolex on this one looks great.
Sounds great! I think the owner will be very happy. Hell I'm happy for him. I do prefer the blue. Now I want one of these for low volume late night playing. It does it quite well. Thanks for showing that Lyle.
Holy crap! I had no idea a modern AC15 could sound so good across so many different tonal flavors. I bought one new about 10 years ago and played it a few times before it was stolen by my landlord. Thankfully I had moved my Martin HD-28, American Strat and a few more of my better pieces of gear before the theft occurred. If I had known what the AC15 could do with some mods it would have been my #1 amp. The tones you got out of it were some of my favorites, that amp without pedals would have done 50% of what I need. An AC15 (or AC30) definitely the next amp I'm going to buy. Thank you so much for this video!
Just finished watching and enjoying the heck out of this video. I just bought an ac15 like this one. I also have a Fender Deluxe Reverb. Would love to send them your way one day.
Thank you for your extensive knowledge Lyle. You've got me wondering about the rectifier in my AC30S1. I (quite obviously) need to locate a service manual and learn more about solid state Vs tube rectification (re. Standby). Ignorance isn't such a great place to be in!! Best regards, and thanks for all you do, Dale Harris
I was never a Vox fan before watching your channel. I just had not experienced them. I'm definitely buying one. Maybe this model used... Thanks for sharing the knowledge...
Sounds ace! Love the clarity and bloom, a bit more freedom to the sound. Anybody would be a lucky person to play this. I have the same amp in black tolex. The green back sounded good but ended up with an alnico gold instead of a blue, still has chime but maybe more low end.
Great video of the mods done and I see your rockin the SG ! Not sure but being your a guitar amp guy look up a guitar player named Frank Mariano of Mahogany Rush fame who solely uses 61 Gibson Lespaul SGs and had a guy build him a custom SG as well from scratch that was used on his Eye of the storm record and CD some years ago .
8:30 -I know you said 'if that had a whole bunch of delay', so I added Echorec to it. I had to get off the couch and play the video through my DAW in the jam room, which sends audio out to Eventide post processors. Yeah, you get some great sounds when you mic up your amps. Dry probably appeals to the most amount of viewers, and I get that. But holy shitskie... that is a great sound. And I really enjoyed the Greenback sounds from the other video too. I caught that right as it was deleted. I was able to watch the entire video and afterwards went to read the 4 comments and it wouldn't allow me. Your wrist is doing better and you're back playing again, love this channel, exceptional sounds, incredible details. Continued success!
My father has one of these. Hadn’t talked to him for a long time and when I started talking to him again I found out he started playing and had all kinds of goodie’s. Myself having played as a teenager was getting back into playing and I finally got my first real tube amp and thought it was a great choice, Marshall DSL 40CR new out of the box 📦. I live in a apartment and I am getting what to my ears a decent tone, but after buying the amp then stumbled across your channel and wonder if I made a good choice? I love a good blues tone but love heavy metal and rock. Also just purchased 2 brand new Epiphone’s one black back custom and a SG traditional pro. Loving it all together so far 🤘
As someone who owns more Marshall than I can justify for home-use (60 watt TSL), I would be willing to bet you’d enjoy something with 15 watts or less much more. Yes, you’re getting a tone that sounds good. But in an apartment, there is no way you’re getting a 40 watt amp in it’s sweet spot. I added a 15 watt blues jr to my collection and prefer it strongly to the Marshall because I can get it to the sweet spot where the amp really opens up. Never understood “the sweet spot” everyone talks about until I had the right size amp for the room I was playing in. Yes, my Marshall produces a sound that is “good” at home volume. But my blues jr gives me an experience at home volume beyond just sounding good. Best way I can describe the difference is that you feel the sound in the air differently when the amp is in the sweet spot and that feeling is awesome.
40 watts is a bit ridiculously overboard for an apartment, you won't be able to enjoy it to it's fullest, unless you have somewhere else to jam. I wouldn't go higher than 15 watts, even 15 is pretty freaking loud. My first tube amp was a Marshal JCM900 switchable between 50-100watts. Even on the 50 watts setting you could hear it down the street, had to turn my amp around at multiple gigs lol knowing what I know now I would have gotten something smaller.
Great stuff. Any experience with the AC4 series? I have one I have tricked a touch with the bright cap mod as well as good tubes and a creamback...for what it is actually it's a pretty nice little amp, especially for a guy like me that lives on a boat...I have interest in 5w watt stuff in general, wondering if you have any feedback on such or recommendations.
brilliant mod, Lyle. i have a pair of these and would love to do this mod at some point. meanwhile i have a question; do you know is there any way to add a power amp-input on the AC15C1? just asking as it would make it a perfect amp (for me) to have that flexibility. love your channel, your dry humor and expertise; and never miss a video. Thanks!
Alnico Blue you stole my heart....oh my. I am continuing to question whether this would make a good home practice amp...but if do get one, i'm going Blue !
Hello from Czech Republic. For home playing AC15C1, would you rather recommend an attenuator or power scaling mod? I don't mind making unreversable changes to my gear, the sound is my priority. Thank you for your advice and your knowledge in general. I'm new to your chanel but a huge fan already.
Hi, feel a kindred spirit musically. Mods and repair wise, you are doing a great service to all us semi pro musicians, just bought an AC15CC1X after reading warning in the advert that the seller reduced the price as the tremelo was only working sometimes if you increased the speed pot to max. Saved £140 after five minutes work in which I simply cleaned the footswitch jack socket and input sockets earth connection a tip I got from this channel, amp is working perfectly now, so bought you a thankyou message and subscribed. Am getting a new AC15C1 for home use this week and want to do the mods Lyle suggested for it, (am a qualified sparks) the normal channel resistor jumper mod I understand, it's just that I cannot find the component values and locations of plate resistor and Tone stack circuit mods? To save lyle's time. Any takers on answering my circuit mod question on the AC15C1, my CC1X sounds superb now, simply after cleaning the earth plates on all relevant cliff style plastic jack sockets, aiming to metal nose if it does not sell on ebay. Any interest in the UK or stateside for a perfect condition Vox AC15CC1X from 2009 that has no issues after fifteen years solid use. Collection preferred from London Uk
Hey there, I'm doing the Lyle Caldwell mods on my AC15C1 now. Did a TON of research and staring at schematics to hopefully not ruin the amp (I'm a mechanical engineering so I'm scared of things with the electricity). As far as I can tell, the values should be below per the schematic. I am yet to check all component numbers but the few have checked makes sense to me 1. Normal channel plate resistor: R5 (original 100k, replace with 200k) 2. TB channel plate resistor: R6 (original 100k, replace with 200k) 3. Normal channel bright cap: C4 (original 120pF, replace with 100pF) 4. TB channel bright cap: C8 (original 120pF, replace with 68pF) 5. Tone stack cap: C13 (original 56pF, replace with 47pF) 6. 330K normal input resistor that needs to be jumpered: R1 (original 330k) 7. Normal Pot lugs 1 and 2 cap can be found on normal volume pot, needs 68pF For reducing filtering, I have ordered Nichicon 22uF and 33uF 450V to replace the stock 47uF. AC15 from JMI appears to have 16uF. This is C62. I also upgraded the screen resistors to 820 3W per Lyle's other AC15C1 video. These are R76 and R87 on the board with the power tube socket parts, original were 470, Lyle recommended 1K 3W. I can not speak for any of the op-amp stuff and will not be attempting it as I can't find any of that information and I am not competent in electronics other than following schematics. I do hear some weird distortion with hot pickups and high gain on the stock amp. I don't have too much tube amp experience but that may be the issue. Let me know if you end up figuring that out. Schematic found here for AC15C1. It's the PDF from the main post. www.diyaudio.com/community/threads/vox-ac15c1-schematics.400094/ Lyle's original post: www.mylespaul.com/threads/vox-ac30-custom-classic-common-issues.127243/ Thanks again Lyle for the great videos and info!
You've got me interested in getting one of these amps. I'm not sure that I have somebody here in Montreal that can do your mods. I know two amp techs...Very cool stuff. You do great work.
3:41 - you could use a too-large resistor, hang a voltage divider off the cathode consisting of a 10k pot and 33k resistor, and end up with adjustable bias via a trim pot. If you want to avoid disturbing the feel of the cathode biased "squish", a 5V Zener in series on the ground side of the stock cathode resistor would work, too, with the 10k bias pot wired in parallel....
That's a lot of stuff to add to a simple circuit. More things to go wrong and there really is no problem to "fix" there. Not trying to shoot you down. When I was newer at amps, I wanted to change every little thing, make everything adjustable. But I've learned that simple is better, and Option Paralysis is very real. Any switch or pot or whatever option I add to a circuit has to justify its existence. And introduce no likely new points of failure. First, do no harm...
Hi again, i have one more question, thank again for the info last time. Just by curiosity, what is the ac signal voltage from the top boost PREAMP maxed. I am trying to figure out what you said about the op-amp not clipping but i must get it wrong because my math are 0,1v comming from a guitar to tube 1 who gives a gain around 60 so 6.0v then to tube 2 60 x 6.0v so 360v ac, then the cathode follower makes it 95% ; so 342v at the U1A input .... Over 36v the calculator says it will clip. What did i got wrong ?
Hi, is there a diagram of the changes you made that I could use to mod mine? If that's proprietary stuff, I totally understand, but I thought I would ask in case! :) Either way, I was wondering what the parts for upgrading cost you? Also, nice Feeling Gravity's Pull! Annnnd do you know anyone around Orange County, CA/ Los Angeles that could do these mods? Thanks!
Prefer the Greenback in these amps anyway, yes the 15W Alnico bluse has more clarity and yet the well bedded in 25W 75 cycles Celestion Greenback in the C1 I tried is definitely the best modern speaker to my ears (so I gave the ampli it to a friend as thanks for the 1962 AC30 with two original Blue Amlinicos he gave me back in the day.)
Since this one has a 1k resistor and a 47uF filter cap instead of a choke, when you change the filter scheme to a spider one, the filtering on the preamp ends up lower than JMI. Do you increase the 47uF filter cap to 100uF(like it is in the C2)to fix that? Thanks!
Thanks man. Absolute best of the best right now? Probably Bartel and Welagen. The next tier down is pretty awesome too. If we make it to Amps Over $3000.... For perspective, a Twin Reverb in '65 was about $3600 when you adjust for inflation. Today we insist on getting what we pay for.
You sure sold me on that modded amp. "10 years gone by," great song, kind of sad. It has more weight as you get older. The best songs are the ones that can affect you emotionally. I think it was one of Led Zeppelin's greatest songs even if it's not very well known.
Can anyone tell me if the “Handwired” version of this amp is worth the quite a bit of extra cost? Are they more reliable, sound any different? Really like the sound of these that he is demo’ing and they seem to be reliable.
Hi Lyle, what do you think the effect of a Creamback in an AC15 would do to the tone overall? Most discussions on the web are middling at best, and I'd rather get the opinion of someone who has a better understanding of the amp. Thanks for your time!
Most of the Vox videos I have on the channel are using my shop cab with the mic on the ET65 which is very similar to the Creamback 65. It’s a very good sound. But you can pretty much judge for yourself.
Very informative and above my pay grade in technicalities but I have a question.... Is it possible to utilize both channels at the same time with a mono signaled splitter phone jack? Or, would that compromise the integrity of the amp??
I don't get putting tweed on a post '61 Fender. I also loathe the C Rex speaker. Both highly subjective opinions. Feel free to disregard. The inside is the same as any other '65 Reissue.
For me they are but only in certain amps like AC30's and Ac15's or any el84 amp that is supposed to be chimey or ringing. For Marshall style amps I prefer the greenback 25 and 30's.
For a vox style amp yes. I switched to alnico blues recently and it really does sound so nice. Big pleasant difference. But I couldn’t imagine putting alnico blues in a fender or Marshall. Maybe it’ll sound awesome idk. They definitely got a big chime to it
interesting but difficult to tell any difference with the mods and speaker change compared to original. we'll just have to take your word for it. keep up the work tho as i learn something every time.
The ones in stock right now. ;) Hard to have preferences this month. The ones I put in for this test are Mullards I keep for test purposes. And they are one of my usual preferences.
Is there a downside (other than physical size for certain layouts) of using 1W carbon films over 1/2W? I know you are often not a fan of 1W metal films in the audio path of tube amplifiers, but won't using higher wattage CARBON FILMS reduce possible noise issues without altering carbon's tonal properties? (Also, you are by far my favorite UA-cam channel, and I never miss a video. Keep up the excellent work.)
Thanks so much! I don't mind 1W metal films in the slightest. Or 1W CFs. On amps like this (PCB) the thing you have to consider is the lead spacing, the component spacing, and the size of the holes in the pads. You don't want to force an oversize component in a PCB location. If I'm restoring an old Fender I use CCs in the audio path. They have some tradeoffs but Fenders are usually fine as far as signal to noise goes. Higher gain amps get CFs or MFs.
@@PsionicAudio Ah. I remember a video of another builder’s Fender-style amp with a lot of 1W metal films that sounded very “hard” when pushed. Is that mostly down to the metal film or the wattage rating or both?
Curious what your thoughts are on the AC30S1. Got one on clearance for around $599 and it’s served me well thus far with a tube swap. Still is quite noisy. Have you seen a lot of these come through your shop?
Hi, i got a few questions, i've looked all over for answers.....please answer 1: in the ac15c1 c68 1nf bypass the cathode follower's cathode resistor.What frequencies are afected ? Would it work without it ( i mean no oscilation). 2 : i noticed that everybody explain how to do the tonestack wrong.If you just ground the 3rd leg you also ground the midle lug and bypass the 10k resistor.( i think it should be lift off the board or the tip of the 3rd leg should be chopped. 3: can you please explain your mod for the attitude switch ( that makes the amp sound more defiant or conqueror). THANK YOU
You’d have to do the math on C68. It won’t oscillate without it - the amp will just be brighter. I think is there to tame things before going through the opamp circuitry which can make transients sound a little hard. I change the bass wiring to JMI and move the 10K resistor accordingly. You have to cut the little trace on the board connecting two lugs of the bass pot. My “attitude” switch is proprietary, sorry. There are only so many secrets in amps, and this one is mine. But it’s essentially a variation on a tone stack lift, though not quite.
@@PsionicAudio hi, i did remove c68, i like it that way. I'm confused about c16 the 120pf between the cathode and plate.Can it be removed (without making other change) without risk ?(oscilation, opamp problems ,etc) And also, i would like to know if you came across bad njm2147d in this amp or another vox ? These seam hard to find, do you order from chinese supplyers ? I think your changes in the opamp network is proprietary, if not can you tell me what resistor has to be change. A guy on a french forum do change r24 and r25 to 660k each, would it lower UA1's gain without making it break. Sorry for so manny questions, i spent hours looking for answers today. I do the mods myself, i did service my 1966 bandmaster last year, i know the importance of clean work , good solder, quality parts, security discharge, multimeter mesurements, etc.
Hey man I just want less bass. I only want bass when I turn the knob up. Can I just change some stuff in that circuit. I'm going to look at it and try to change the tone caps or something
Houston we have a problem. My Peavey Windsor Studio combo hums when the reverb is turned up. It has the Mo Jo tank in it. I took the reverb tank from my Marshall Reverb 75 and put in the Peavey and the Peavey into the Marshall. Still hums. Swapped tubes in the Peavey too. I do have Fluke meter but not sure where to test. Arrrg.
$350 this month. I don't want someone to read that in five years and be mad that prices change. Like I said in the video though, I'm trying to get through a backlog before taking in any more RI amps (Fender, Vox, etc) for tweaks. Want to get back to a better turnaround time. Distribution issues have caused a lot of behind the scenes wailing and gnashing of teeth.
Should one of the EL84’s decide to shit the bed. That now referred as “My tubes pulled an Amber Heard”. 😂 Okay, all kidding aside, you are an absolute mad scientist when it comes to modding amps to make them perform at their absolute peak performance. To you, it may just seem like something you do. But to laymen like myself, it’s a pleasure to watch and hear you explain the details you get into.
Actually GB are pretty nice speakers if you play cleans and edge of break up tones, especially is a 212 cab. If you play heavy gain mid scooped tones there is better choices . Volume is also a big big consideration when we discuss speakers: at bedroom volume there is not a single speaker that really sounds good. Guitar speakers are meant to be used at stage volume
The greenback is awesome, it just doesn’t belong in a vox. When I switched to alnico blues, i sold one Greenback and kept the other one and paired it with an orange amp. It was rockin’ I don’t play classic rock but it’s nice to have that sound available
Worth it to hear the REM and Radiohead riffs again. Nice. That Alnico Blue sounds ace. I have a Creamback in my AC15C1...now I want a Blue. I wonder how much difference it will make?
They are very different but both excellent. Like choosing between two really good gelatos on a hot day .. God I miss Florence. It would be worthwhile to get the matching 1x12 extension cab and having the Blue AND the Creamback. You could use both on larger stages, would know what your preference is for going in the combo for small stages, and alternate or blend for recording. Remember that an AC15 into two 12" speakers is about the same volume as an AC30 into one 12" speaker.
dang Vox have been making amps for year. now you come around and say Vox not making right . dang people like you should . Been using AC15 for years and no problem
Wow… I have played my AC15 for 10+ years and love it, but these mods really brought it to a new level. Thank you.
Vox AC’s are the Goldie Locks of amps: not too sterile clean, not too much distorted roar. They’re “just right.” The red tolex on this one looks great.
Sounds great! I think the owner will be very happy. Hell I'm happy for him. I do prefer the blue. Now I want one of these for low volume late night playing. It does it quite well. Thanks for showing that Lyle.
Appreciating the song selections.
Holy crap! I had no idea a modern AC15 could sound so good across so many different tonal flavors. I bought one new about 10 years ago and played it a few times before it was stolen by my landlord. Thankfully I had moved my Martin HD-28, American Strat and a few more of my better pieces of gear before the theft occurred. If I had known what the AC15 could do with some mods it would have been my #1 amp. The tones you got out of it were some of my favorites, that amp without pedals would have done 50% of what I need. An AC15 (or AC30) definitely the next amp I'm going to buy. Thank you so much for this video!
Just finished watching and enjoying the heck out of this video. I just bought an ac15 like this one. I also have a Fender Deluxe Reverb. Would love to send them your way one day.
Great video! 2x 270ohms 3W resistors in parallel for the cathode resistor worked nicely for me
That thing sounds ACE! So much better sounding than in the first vid.
Great work love your videos thank you for sharing!
Thank you for your extensive knowledge Lyle. You've got me wondering about the rectifier in my AC30S1. I (quite obviously) need to locate a service manual and learn more about solid state Vs tube rectification (re. Standby). Ignorance isn't such a great place to be in!!
Best regards, and thanks for all you do,
Dale Harris
I was never a Vox fan before watching your channel. I just had not experienced them. I'm definitely buying one. Maybe this model used... Thanks for sharing the knowledge...
Wowwww that amp sounds incredible after those mods!!!!
Sounds really nice.
Sound so good nice job 👍
Good lord. It’s very selfish of me, I know, but sooo wish you were in southern CA. Keep up the great work and fascinating videos!
Sounds ace! Love the clarity and bloom, a bit more freedom to the sound. Anybody would be a lucky person to play this.
I have the same amp in black tolex. The green back sounded good but ended up with an alnico gold instead of a blue, still has chime but maybe more low end.
Nice playing! The amp is more alive now.
Feeling gravity’s pull nice one 👍. The live version off tourfilm is amazing. Peter Buck’s tone at its best.
Lacking a Rick and not wanting to hook up a chorus, I went for the live version feel. ;)
I greatly enjoy your work and your videos, plus as a former roadie for REM I tend to really enjoy your playing, too!
Apologies to Peter - I haven’t gotten the Rick yet.
Yet…
Great video of the mods done and I see your rockin the SG ! Not sure but being your a guitar amp guy look up a guitar player named Frank Mariano of Mahogany Rush fame who solely uses 61 Gibson Lespaul SGs and had a guy build him a custom SG as well from scratch that was used on his Eye of the storm record and CD some years ago .
Absolute bliss. Next level sonics.
I want to know how to do this to my AC15C1!!! Wow! Epic!
A Celestion Ruby is a good speaker change it rolls off top end and means you do not need to mess with the high clip.
8:30 -I know you said 'if that had a whole bunch of delay', so I added Echorec to it. I had to get off the couch and play the video through my DAW in the jam room, which sends audio out to Eventide post processors.
Yeah, you get some great sounds when you mic up your amps. Dry probably appeals to the most amount of viewers, and I get that. But holy shitskie... that is a great sound. And I really enjoyed the Greenback sounds from the other video too. I caught that right as it was deleted. I was able to watch the entire video and afterwards went to read the 4 comments and it wouldn't allow me.
Your wrist is doing better and you're back playing again, love this channel, exceptional sounds, incredible details. Continued success!
Thanks Jim! I deleted the previous video because it wasn't fair to the Blue - turns out a tube was dying. Would have just confused a lot of people.
My father has one of these. Hadn’t talked to him for a long time and when I started talking to him again I found out he started playing and had all kinds of goodie’s. Myself having played as a teenager was getting back into playing and I finally got my first real tube amp and thought it was a great choice, Marshall DSL 40CR new out of the box 📦. I live in a apartment and I am getting what to my ears a decent tone, but after buying the amp then stumbled across your channel and wonder if I made a good choice? I love a good blues tone but love heavy metal and rock. Also just purchased 2 brand new Epiphone’s one black back custom and a SG traditional pro. Loving it all together so far 🤘
As someone who owns more Marshall than I can justify for home-use (60 watt TSL), I would be willing to bet you’d enjoy something with 15 watts or less much more.
Yes, you’re getting a tone that sounds good. But in an apartment, there is no way you’re getting a 40 watt amp in it’s sweet spot.
I added a 15 watt blues jr to my collection and prefer it strongly to the Marshall because I can get it to the sweet spot where the amp really opens up. Never understood “the sweet spot” everyone talks about until I had the right size amp for the room I was playing in. Yes, my Marshall produces a sound that is “good” at home volume. But my blues jr gives me an experience at home volume beyond just sounding good. Best way I can describe the difference is that you feel the sound in the air differently when the amp is in the sweet spot and that feeling is awesome.
Feel the fatherly love
40 watts is a bit ridiculously overboard for an apartment, you won't be able to enjoy it to it's fullest, unless you have somewhere else to jam. I wouldn't go higher than 15 watts, even 15 is pretty freaking loud. My first tube amp was a Marshal JCM900 switchable between 50-100watts. Even on the 50 watts setting you could hear it down the street, had to turn my amp around at multiple gigs lol knowing what I know now I would have gotten something smaller.
Wow. I see why you like this amp. It sounds really good!
Great stuff. Any experience with the AC4 series? I have one I have tricked a touch with the bright cap mod as well as good tubes and a creamback...for what it is actually it's a pretty nice little amp, especially for a guy like me that lives on a boat...I have interest in 5w watt stuff in general, wondering if you have any feedback on such or recommendations.
brilliant mod, Lyle. i have a pair of these and would love to do this mod at some point. meanwhile i have a question; do you know is there any way to add a power amp-input on the AC15C1? just asking as it would make it a perfect amp (for me) to have that flexibility. love your channel, your dry humor and expertise; and never miss a video. Thanks!
Where on earth did you get that T-Shirt with a board printed on it? Super Cool 😎
i dont think i could any repairs but i like to watch you videos thanks
what is you opinion about orange rocker ?
Alnico Blue you stole my heart....oh my. I am continuing to question whether this would make a good home practice amp...but if do get one, i'm going Blue !
In my experience, yes, if you can resist the temptation to raise the master volume. ;)
@@PsionicAudio Good luck with that!
Hello from Czech Republic. For home playing AC15C1, would you rather recommend an attenuator or power scaling mod? I don't mind making unreversable changes to my gear, the sound is my priority. Thank you for your advice and your knowledge in general. I'm new to your chanel but a huge fan already.
Thanks
Hi, feel a kindred spirit musically. Mods and repair wise, you are doing a great service to all us semi pro musicians, just bought an AC15CC1X after reading warning in the advert that the seller reduced the price as the tremelo was only working sometimes if you increased the speed pot to max. Saved £140 after five minutes work in which I simply cleaned the footswitch jack socket and input sockets earth connection a tip I got from this channel, amp is working perfectly now, so bought you a thankyou message and subscribed. Am getting a new AC15C1 for home use this week and want to do the mods Lyle suggested for it, (am a qualified sparks) the normal channel resistor jumper mod I understand, it's just that I cannot find the component values and locations of plate resistor and Tone stack circuit mods? To save lyle's time. Any takers on answering my circuit mod question on the AC15C1, my CC1X sounds superb now, simply after cleaning the earth plates on all relevant cliff style plastic jack sockets, aiming to metal nose if it does not sell on ebay. Any interest in the UK or stateside for a perfect condition Vox AC15CC1X from 2009 that has no issues after fifteen years solid use. Collection preferred from London Uk
Hey there, I'm doing the Lyle Caldwell mods on my AC15C1 now. Did a TON of research and staring at schematics to hopefully not ruin the amp (I'm a mechanical engineering so I'm scared of things with the electricity). As far as I can tell, the values should be below per the schematic. I am yet to check all component numbers but the few have checked makes sense to me
1. Normal channel plate resistor: R5 (original 100k, replace with 200k)
2. TB channel plate resistor: R6 (original 100k, replace with 200k)
3. Normal channel bright cap: C4 (original 120pF, replace with 100pF)
4. TB channel bright cap: C8 (original 120pF, replace with 68pF)
5. Tone stack cap: C13 (original 56pF, replace with 47pF)
6. 330K normal input resistor that needs to be jumpered: R1 (original 330k)
7. Normal Pot lugs 1 and 2 cap can be found on normal volume pot, needs 68pF
For reducing filtering, I have ordered Nichicon 22uF and 33uF 450V to replace the stock 47uF. AC15 from JMI appears to have 16uF. This is C62.
I also upgraded the screen resistors to 820 3W per Lyle's other AC15C1 video. These are R76 and R87 on the board with the power tube socket parts, original were 470, Lyle recommended 1K 3W.
I can not speak for any of the op-amp stuff and will not be attempting it as I can't find any of that information and I am not competent in electronics other than following schematics. I do hear some weird distortion with hot pickups and high gain on the stock amp. I don't have too much tube amp experience but that may be the issue. Let me know if you end up figuring that out.
Schematic found here for AC15C1. It's the PDF from the main post. www.diyaudio.com/community/threads/vox-ac15c1-schematics.400094/
Lyle's original post: www.mylespaul.com/threads/vox-ac30-custom-classic-common-issues.127243/
Thanks again Lyle for the great videos and info!
Sound awesome. Did you change two resistors on power tubes from 470 ohm to 1k?
sweet sounding amp, and nice cross-section of tunes!
You've got me interested in getting one of these amps. I'm not sure that I have somebody here in Montreal that can do your mods. I know two amp techs...Very cool stuff. You do great work.
Thanks Kim. My buddy Chris Church at Church Audio in Hamilton ON could do these for you.
@@PsionicAudio Thanks for that.
Tell him Lyle sent you.
@@PsionicAudio Thanks!
@@PsionicAudio any chance you can recommend someone in Minneapolis / St. Paul, MN ? Thanks!
3:41 - you could use a too-large resistor, hang a voltage divider off the cathode consisting of a 10k pot and 33k resistor, and end up with adjustable bias via a trim pot. If you want to avoid disturbing the feel of the cathode biased "squish", a 5V Zener in series on the ground side of the stock cathode resistor would work, too, with the 10k bias pot wired in parallel....
The mods you did sound great, BTW....
That's a lot of stuff to add to a simple circuit. More things to go wrong and there really is no problem to "fix" there. Not trying to shoot you down.
When I was newer at amps, I wanted to change every little thing, make everything adjustable. But I've learned that simple is better, and Option Paralysis is very real.
Any switch or pot or whatever option I add to a circuit has to justify its existence. And introduce no likely new points of failure.
First, do no harm...
@@PsionicAudioOption paralysis. Perfect description.
Hi again, i have one more question, thank again for the info last time. Just by curiosity, what is the ac signal voltage from the top boost PREAMP maxed. I am trying to figure out what you said about the op-amp not clipping but i must get it wrong because my math are 0,1v comming from a guitar to tube 1 who gives a gain around 60 so 6.0v then to tube 2 60 x 6.0v so 360v ac, then the cathode follower makes it 95% ; so 342v at the U1A input .... Over 36v the calculator says it will clip. What did i got wrong ?
Hi, is there a diagram of the changes you made that I could use to mod mine? If that's proprietary stuff, I totally understand, but I thought I would ask in case! :)
Either way, I was wondering what the parts for upgrading cost you? Also, nice Feeling Gravity's Pull! Annnnd do you know anyone around Orange County, CA/ Los Angeles that could do these mods? Thanks!
Prefer the Greenback in these amps anyway, yes the 15W Alnico bluse has more clarity and yet the well bedded in 25W 75 cycles Celestion Greenback in the C1 I tried is definitely the best modern speaker to my ears (so I gave the ampli it to a friend as thanks for the 1962 AC30 with two original Blue Amlinicos he gave me back in the day.)
Since this one has a 1k resistor and a 47uF filter cap instead of a choke, when you change the filter scheme to a spider one, the filtering on the preamp ends up lower than JMI.
Do you increase the 47uF filter cap to 100uF(like it is in the C2)to fix that?
Thanks!
And another thing, what do you set your tone controls on neck/bridge... 10?
Love all the tunes you played.......what kind of guitar are you playing ?
Thanks! One of my Strats and my SG. Videos on both guitars on the channel.
I like vox
Which amp brand is built (engineered) the best that you’ve experienced? Your videos are great! 👍😎
Thanks man. Absolute best of the best right now? Probably Bartel and Welagen. The next tier down is pretty awesome too. If we make it to Amps Over $3000....
For perspective, a Twin Reverb in '65 was about $3600 when you adjust for inflation.
Today we insist on getting what we pay for.
@@PsionicAudio
Good grief... I just about fell out of my chair. Straight answer to a question... I never seen one of those before!
My Vox has a Celestion G12M 65 watt....Gold back.
You sure sold me on that modded amp. "10 years gone by," great song, kind of sad. It has more weight as you get older. The best songs are the ones that can affect you emotionally. I think it was one of Led Zeppelin's greatest songs even if it's not very well known.
Can anyone tell me if the “Handwired” version of this amp is worth the quite a bit of extra cost? Are they more reliable, sound any different? Really like the sound of these that he is demo’ing and they seem to be reliable.
Have you ever worked on a Vox AC10 SRT? The one I have heard on Doug and Pats youtube channel sound very good.
I'd like to. But they are very rare.
Good news, Chords are free, specially power chords
Hi Lyle, what do you think the effect of a Creamback in an AC15 would do to the tone overall? Most discussions on the web are middling at best, and I'd rather get the opinion of someone who has a better understanding of the amp. Thanks for your time!
Most of the Vox videos I have on the channel are using my shop cab with the mic on the ET65 which is very similar to the Creamback 65. It’s a very good sound. But you can pretty much judge for yourself.
Very informative and above my pay grade in technicalities but I have a question....
Is it possible to utilize both channels at the same time with a mono signaled splitter phone jack? Or, would that compromise the integrity of the amp??
You can. You’ll just slightly take off some highs.
What is the name of that Zeppelin riff he plays at the beginning of the sound demo ? I cannot think of it for the life of me. Great video btw
With the SG? Ten Years Gone. Thanks!
@@PsionicAudio ahhhhh, thank you man. Love your videos dude, I have the ac15c1x and it's been an absolutely lovely amp.
Wondering what your thoughts would be on the 65 Princeton Tweed with the Cannabis rex long and mcquade is offering?
I don't get putting tweed on a post '61 Fender. I also loathe the C Rex speaker.
Both highly subjective opinions. Feel free to disregard.
The inside is the same as any other '65 Reissue.
How much did these mods cost?
You mentioned that you have no interest in selling your mods, but jeez, they make the amplifier so much better and more
Reliable and serviceable…
Well, you said your crappy playing??? I am enjoying your "crappy" playing as you make them. ;)
Are Celestion Alnico Blue's the best speaker ever made?
Discuss amongst yourselves.
For me they are but only in certain amps like AC30's and Ac15's or any el84 amp that is supposed to be chimey or ringing. For Marshall style amps I prefer the greenback 25 and 30's.
For a vox style amp yes. I switched to alnico blues recently and it really does sound so nice. Big pleasant difference.
But I couldn’t imagine putting alnico blues in a fender or Marshall. Maybe it’ll sound awesome idk. They definitely got a big chime to it
The Ruby is better in the AC15C1
interesting but difficult to tell any difference with the mods and speaker change compared to original. we'll just have to take your word for it. keep up the work tho as i learn something every time.
I'll do another playing video for this amp after its new tubes and reverb tank arrive. I only scratched the surface here as the video was going long.
@@PsionicAudio thanks, would like to hear that as i have the same year amp in blue/cream. what el84s are you going to use?
The ones in stock right now. ;)
Hard to have preferences this month.
The ones I put in for this test are Mullards I keep for test purposes. And they are one of my usual preferences.
Is there a downside (other than physical size for certain layouts) of using 1W carbon films over 1/2W? I know you are often not a fan of 1W metal films in the audio path of tube amplifiers, but won't using higher wattage CARBON FILMS reduce possible noise issues without altering carbon's tonal properties? (Also, you are by far my favorite UA-cam channel, and I never miss a video. Keep up the excellent work.)
Thanks so much!
I don't mind 1W metal films in the slightest. Or 1W CFs. On amps like this (PCB) the thing you have to consider is the lead spacing, the component spacing, and the size of the holes in the pads. You don't want to force an oversize component in a PCB location.
If I'm restoring an old Fender I use CCs in the audio path. They have some tradeoffs but Fenders are usually fine as far as signal to noise goes. Higher gain amps get CFs or MFs.
@@PsionicAudio Ah. I remember a video of another builder’s Fender-style amp with a lot of 1W metal films that sounded very “hard” when pushed. Is that mostly down to the metal film or the wattage rating or both?
Curious what your thoughts are on the AC30S1. Got one on clearance for around $599 and it’s served me well thus far with a tube swap.
Still is quite noisy. Have you seen a lot of these come through your shop?
I haven't had one on the bench. So no opinion.
Where do I mail mine?
Hi, i got a few questions, i've looked all over for answers.....please answer 1: in the ac15c1 c68 1nf bypass the cathode follower's cathode resistor.What frequencies are afected ? Would it work without it ( i mean no oscilation). 2 : i noticed that everybody explain how to do the tonestack wrong.If you just ground the 3rd leg you also ground the midle lug and bypass the 10k resistor.( i think it should be lift off the board or the tip of the 3rd leg should be chopped. 3: can you please explain your mod for the attitude switch ( that makes the amp sound more defiant or conqueror). THANK YOU
You’d have to do the math on C68. It won’t oscillate without it - the amp will just be brighter. I think is there to tame things before going through the opamp circuitry which can make transients sound a little hard.
I change the bass wiring to JMI and move the 10K resistor accordingly. You have to cut the little trace on the board connecting two lugs of the bass pot.
My “attitude” switch is proprietary, sorry. There are only so many secrets in amps, and this one is mine. But it’s essentially a variation on a tone stack lift, though not quite.
@@PsionicAudio thanks alot, for answering, i didnt think about the opamp when i was looking at c68, it makes scence.
@@PsionicAudio hi, i did remove c68, i like it that way. I'm confused about c16 the 120pf between the cathode and plate.Can it be removed (without making other change) without risk ?(oscilation, opamp problems ,etc) And also, i would like to know if you came across bad njm2147d in this amp or another vox ? These seam hard to find, do you order from chinese supplyers ? I think your changes in the opamp network is proprietary, if not can you tell me what resistor has to be change. A guy on a french forum do change r24 and r25 to 660k each, would it lower UA1's gain without making it break. Sorry for so manny questions, i spent hours looking for answers today. I do the mods myself, i did service my 1966 bandmaster last year, i know the importance of clean work , good solder, quality parts, security discharge, multimeter mesurements, etc.
Anyone Try one of these with the Celestion Gold?
Hey man I just want less bass. I only want bass when I turn the knob up. Can I just change some stuff in that circuit. I'm going to look at it and try to change the tone caps or something
Don’t start changing things. This is not an amp to learn how to work on amps with. Take it to a tech if necessary but the stock amp is not bass heavy.
I was a better player a decade ago but there's Ten Years Gone so now I wanna be a Paperback Writer.
I enjoy listening to your guitar playing and no matter how poorly you claim to be playing it’s light years ahead of where I will ever be.
Houston we have a problem. My Peavey Windsor Studio combo hums when the reverb is turned up. It has the Mo Jo tank in it. I took the reverb tank from my Marshall Reverb 75 and put in the Peavey and the Peavey into the Marshall. Still hums. Swapped tubes in the Peavey too. I do have Fluke meter but not sure where to test. Arrrg.
Take it to a tech. There are reasons we exist.
@@PsionicAudio Good idea. I’m lucky I’m alive, I bypassed the power sponge and survived.
Can I be forward and ask what the approx cost Of these mods are on the voxAC15SC1?
$350 this month. I don't want someone to read that in five years and be mad that prices change.
Like I said in the video though, I'm trying to get through a backlog before taking in any more RI amps (Fender, Vox, etc) for tweaks.
Want to get back to a better turnaround time. Distribution issues have caused a lot of behind the scenes wailing and gnashing of teeth.
Interesting expression,, shit the bed. I had a friend who modified that to shit the bed and roll in it!
My AC15C1 buzzes with my Strat....but is quiet with my Les Paul ?
That’s more likely single coil buzz than any problem with your amp.
9:04 don't dream it's over?
Can you do this to my AC15C1?
Probably better to email him. Check video description.
Should one of the EL84’s decide to shit the bed. That now referred as “My tubes pulled an Amber Heard”. 😂 Okay, all kidding aside, you are an absolute mad scientist when it comes to modding amps to make them perform at their absolute peak performance. To you, it may just seem like something you do. But to laymen like myself, it’s a pleasure to watch and hear you explain the details you get into.
the greenback is terrible imo. I put a WGS ET65 in mine a few years back. It made a world of difference.
The greenback is NOT a terrible speaker.
But greenbacks and small open back cabs are not a good recipe for tone.
A saw makes a terrible hammer.
Actually GB are pretty nice speakers if you play cleans and edge of break up tones, especially is a 212 cab. If you play heavy gain mid scooped tones there is better choices . Volume is also a big big consideration when we discuss speakers: at bedroom volume there is not a single speaker that really sounds good. Guitar speakers are meant to be used at stage volume
The greenback is awesome, it just doesn’t belong in a vox. When I switched to alnico blues, i sold one Greenback and kept the other one and paired it with an orange amp. It was rockin’
I don’t play classic rock but it’s nice to have that sound available
@@marcospintor1333 great point!
Hmmmmm, I have a Weber Blue Dog sitting in the closet. I think it needs a new amp.......
All the copyright strikes
Worth it to hear the REM and Radiohead riffs again. Nice. That Alnico Blue sounds ace. I have a Creamback in my AC15C1...now I want a Blue. I wonder how much difference it will make?
They are very different but both excellent. Like choosing between two really good gelatos on a hot day ..
God I miss Florence.
It would be worthwhile to get the matching 1x12 extension cab and having the Blue AND the Creamback. You could use both on larger stages, would know what your preference is for going in the combo for small stages, and alternate or blend for recording.
Remember that an AC15 into two 12" speakers is about the same volume as an AC30 into one 12" speaker.
dang Vox have been making amps for year. now you come around and say Vox not making right . dang people like you should . Been using AC15 for years and no problem
what are your thoughts on the bright cap removal a lot of people do on these? both TB and normal channels? cheers