There's hardly anyone better than you to do videos explaining how those circuits work. You're helping preserve the knowledge that could have disappeared completely from planet earth at the pace electronic replacement stuff is taking over. So thank you once again for that.
Your channel and analysis is why I went to a private builder when looking for a new Plexi. I chose Germino Amps and his Lead55 which is a late 1960's Marshall clone with top notch components. From order to delivery was 14 weeks but it was well worth it. It's absolutely silent and the sound quality is pure Marshall Plexi tone monster. To hell with Marshall and the crap they're putting in the amps these days. They've raced to the bottom and I had no intention of following them after being utterly snd thoroughly disappointed in my JCM800. Now I've got a great Marshall amp made by someone else and an expensive Marshall made door stop.
I am sold on your expertise, Jason! I love the mods you do on Marshalls. I'll be looking for a used Alta v2 someday. It will be much more affordable than new.
I think Marshall needs to be roasted a bit but I doubt they'll listen 😂 luckily guys like Jason are making the amps and circuits we want that Marshall seems allergic to
Thank you for all of your videos covering Marshall amplifiers...after all, NEARLY EVERY ROCK album I love from A-Z used Marshall amps!!! That is A LOT OF LEGENDARY BANDS!!! RESPECT!!! 👍🤯
Awesome stuff man .... as it usually is !! - I have been contemplating adding a tube Gain stage to my '75 1959 for some time now, .... just didn't know exactly how to approach it. You have helped demystify the process for me - much appreciaited !! - Great content man .... Thanks for sharing Jason !!
It looks so weird not seeing DPDT pot at the treble for a Jose mod 😆 I'm very glad Marshall decided to relabel the transformer codes to remove the old Dagnall codes and used MAV... great video 🤘
That’s a surprisingly simple mod with a small number of components, but so effective! Amp sounds fantastic. One of my planned builds this year is a fully hot rodded Marshall Plexi so this gives me ideas! But first, I have to build the Headfirst MCII - it’s been waiting far too long! Thanks Jason. Have an awesome day.
G'day Jase, I picked up an amp from Alex last week, and although Alex had packed it with 4kg of bubble wrap and double boxed with tons of fragile tape, Australia post must have throen it in the back of the van and let it roll around because the bright switch and gain pot was mangled when it arrived. Alex sent me a new one prewired and i had to open it up and swap out the parts. It was pretty simple but very intimidating because its the first time I've worked on an amp. I'm incredibly impressed by it
Having that extra hole for the preamp tube already in the chassis is nice. Guess that a throwback to the old Tremolo heads. Would love to do this to a 1987, but they don’t have that extra knockout in the chassis.
Here we go again Marshall not useing there stick pt again like the last video you did. Buying a Marshall is over with me. In the next few mouths i want to talk about getting a 50 watt Cali amp. Thanks Jason
Great video thanks. What is the reason for the 4 capacitors over the rectifier diodes, and what values are used? (Sorry if you did cover it, I have only had the time to skip through the video at the moment.)
Jason only as a hypothetical guess since you were not there but do have great ears do you think EVH had Jose do anything to his 12301 for that first record? It just strikes me as odd how the gain "seemed" to be more abundant on that record than it's successor VH II and WACF? Some believe Ed used a pedal for the extra gain but he said he was admittedly dead against OD pedals? There was a plugged hole on the back of 12301 by late 78 after that record had been out for a bit?
That plug at the rear remains a mystery huh. But a great plexi down on a variac, biased and then dimed is an amazing thing and has heaps of gain. Put an ep boost or a 10 band graphic in front - it gets you there. Short answer, no I don’t think the amp was modded other than the fat cap and the 50k mid pot.
Another rookie question: Where does the red cable attached to pin 1 of the added 4-pin tag board go? I guess somewhere on the bottom of the main board, but where exactly?
what about the SUPER PA? Been thinking on modding my 69(metal plate) super pa 50, having 4 input channels and already having the extra pots and tube....
We’ll done videos, subbed. I have this preamp in a floor pedal format with separate paths for the vintage/800 and the Jose circuit. I tried the 20v ZD 16/24v and the trannies, but I think I prefer Red LED’s for the clipper. Seems grainier and smooth with a nice top. Bit more volume drop so I added some series resistance (100k pot) to help dial them in. Have you ever played with LED’s in this circuit?
Great video!! I just built my first 50w 2204 from Modulus with the Jake E Lee mods. Question: Why are there caps in parallel on the diodes in this amp? Is it just for more smoothing.
Super neat, love me some basics. Nerd question: Someone once told me that putting the master at the indicator light position can increase noise because it's so close to the power input. Thought on that? Also, I have a feeling that you know a thing or two about setting up a guitar. I just took my two PRS CE-22 from decked to floating and it blew my mind how alive one of them cave. Went from a dull warm mess to an aggressive attacky beast. However, I hate that I can't do double stops any more! If you have any general input on settings up trems, blocking them, etc, that could be a cool video idea in the future.
I guess in theory you could get some interference from the power, however I’ve never experienced it. I think it’s ok. Floating trems are a whole ballgame to themselves aren’t they. I grew up with a JEM in my hands so I’m comfortable with them….i put one of those tremol-no things on a guitar with a floating bridge to allow it to be locked…worked pretty great.
I have a jcm800 Kerry king signature head. I was wondering is it possible to put a footswitch on the back so I can turn the beast mode on and off? If your using this amp live you cannot switch to a cleaner sound without clicking the beast mode button off manually.
Hi i have one of these amps. i bought it from the wife of just past husband. and i bleive it to be a 2005 { apparently the first year production}!!! On the Marshall web site it goes into high detail how much effort the put into recreating the original output transformer!!!!! Long Story Short i basical blew the amp up in the first few test drives!!! Going full rock and roll Full blast and drunk!!! I beleve my Tech to Be Very Qualifed and expressed that i wanted the MAGIC out put transformer to be supplied by MARSHALL and re installed!! Unfotuantly he ignord my request and said he just contacted Marshall for a 100 Watt output Trans!! Any opinions would be appreciated!! Even just for a old fassioned Yarn!! Thanks
When you do the 68/68k voltage divider, do you still need the 68k on v1 grid? So I see here, but I don't think I see it on the Jose schematic. Maybe i'm not reading it right
It is amazing how a little easy mod like this can change the sound of the amp drastically. Thanks for the overview! Do you think this can be done with the small SV20H too? I have recently got a used one for an amazing price ($500), and I was thinking about modding it.
Thanks for the idea and vid. I have a stock 1959hw from, I think 2021... was the PT Vietnamese or made in England then? Is that a Friedman JEL 100 head I see?
Hi Jason ....again a great video, thx for all the infos ....fantastic sounding amp .... i have 2 questions: Is that mod something similar as a hardwired version of the "Legendary Tones Hot mod" ? I see that you use a SM57 into the Apollo interface ... do you use a unison Preamp plugin in your Apollo and if yes , which one do you like ... i really like your tones. Thanks , all the best from Luxembourg , Tosch
Hot mod is just an extra stage at v2 isn’t it? This is not that. This is an extra stage out front, and an added master volume which a hot mod won’t deliver. Unison preamp, yes. Just one of the free UA ones that came with the unit.
Not the same thing in that it’s in a different place in the circuit, doesn’t add a master volume and will have different interstage dividers. Same as in yeah, it’s an extra gain stage.
Hi! I am considering doing this mod as my first one... Is there a particular reason not to put the Master Volume pot above the Gain Pot for the added gain stage? Space? Interference? Other? Thanks for looking into my question :)
It’s never a great idea to run a signal that’s at the end of the preamp all the way back to where the input jack is. You can shield etc, but it’s still a bad choice layout wise.
@@HeadfirstAmps Thanks a lot for taking the time to answer this rookie question, mate! I was sure there is a good reason for that, but I was hoping there could be a chance to avoid having to drill the plexi front panel...
@@HeadfirstAmps lol... No I didn't mean the master volume part of course... The gain part is what I was referring to. Thanks for answering and keep up the great vids. This one sounds killer!!
There's hardly anyone better than you to do videos explaining how those circuits work. You're helping preserve the knowledge that could have disappeared completely from planet earth at the pace electronic replacement stuff is taking over. So thank you once again for that.
Thanks bro!
Your channel and analysis is why I went to a private builder when looking for a new Plexi. I chose Germino Amps and his Lead55 which is a late 1960's Marshall clone with top notch components. From order to delivery was 14 weeks but it was well worth it. It's absolutely silent and the sound quality is pure Marshall Plexi tone monster. To hell with Marshall and the crap they're putting in the amps these days. They've raced to the bottom and I had no intention of following them after being utterly snd thoroughly disappointed in my JCM800. Now I've got a great Marshall amp made by someone else and an expensive Marshall made door stop.
I am sold on your expertise, Jason! I love the mods you do on Marshalls. I'll be looking for a used Alta v2 someday. It will be much more affordable than new.
You can talk freely about those transformers mate! We want to hear your thoughts. That's why we're here!
I think Marshall needs to be roasted a bit but I doubt they'll listen 😂 luckily guys like Jason are making the amps and circuits we want that Marshall seems allergic to
This is Gold ! Because of you I have built my first Marshall 20 watt Clone ! Thanks Jason .Vic from Vancouver .
That is awesome!
Thank you for all of your videos covering Marshall amplifiers...after all, NEARLY EVERY ROCK album I love from A-Z used Marshall amps!!! That is A LOT OF LEGENDARY BANDS!!! RESPECT!!! 👍🤯
Guys ! Hit the like for Jason , he makes killer videos !
Awesome stuff man .... as it usually is !! - I have been contemplating adding a tube Gain stage to my '75 1959 for some time now, .... just didn't know exactly how to approach it. You have helped demystify the process for me - much appreciaited !! - Great content man .... Thanks for sharing Jason !!
Do you have to drill into it or are the holes already there?
Beautiful, this is how you do it. Bought and direct to Tech, i wish Jason lived in California
I can buy you one here, mod it and send it! Marshall prices here are way cheaper!
Aloha Jason thanks for the mod. I prefer the way you set it up.
Sounds fantastic, but no surprises there. Great work as usual.
Amp
Aside. Sick Kramer. Glad I’m not the only one stuck in the 80’s lol. 2024 is the new 1984
Hell yeah!
It looks so weird not seeing DPDT pot at the treble for a Jose mod 😆 I'm very glad Marshall decided to relabel the transformer codes to remove the old Dagnall codes and used MAV... great video 🤘
That’s a surprisingly simple mod with a small number of components, but so effective! Amp sounds fantastic. One of my planned builds this year is a fully hot rodded Marshall Plexi so this gives me ideas! But first, I have to build the Headfirst MCII - it’s been waiting far too long! Thanks Jason. Have an awesome day.
It’s a classic!
G'day Jase, I picked up an amp from Alex last week, and although Alex had packed it with 4kg of bubble wrap and double boxed with tons of fragile tape, Australia post must have throen it in the back of the van and let it roll around because the bright switch and gain pot was mangled when it arrived. Alex sent me a new one prewired and i had to open it up and swap out the parts. It was pretty simple but very intimidating because its the first time I've worked on an amp. I'm incredibly impressed by it
I only ship TNT and FedEx for international. They seem to know more about handling parcels. What was the amp?
@@HeadfirstAmps I just sent you some pics on messenger
Having that extra hole for the preamp tube already in the chassis is nice. Guess that a throwback to the old Tremolo heads. Would love to do this to a 1987, but they don’t have that extra knockout in the chassis.
killer sound
Yeah and that Malcolm Marshall was a beast also! it had the best "Keraang" i have heard in a while!🤘
Here we go again Marshall not useing there stick pt again like the last video you did. Buying a Marshall is over with me.
In the next few mouths i want to talk about getting a 50 watt Cali amp. Thanks Jason
Good stuff
Thanks for waking through that.
It just has that sound. Probably over the top to have the cathode bypassed on the cathode follower, but it sounds great here. 😊
Varies from amp to amp, I chose that by ear.
@@HeadfirstAmps good ears 😊
Wondering with the new Vietnamese PS, concerns about adding another heater to the heater winding?
Excellent as always!
Another Awesome video. Bravo 🙌
Just amazing to watch your vids.
Perfection!
Awesome what a wonderful sound
Nice work!
Always buy vintage 😜🤘
Great video thanks. What is the reason for the 4 capacitors over the rectifier diodes, and what values are used? (Sorry if you did cover it, I have only had the time to skip through the video at the moment.)
Could you use a push/pull on volume pot for diodes?
Jason only as a hypothetical guess since you were not there but do have great ears do you think EVH had Jose do anything to
his 12301 for that first record? It just strikes me as odd how the gain "seemed" to be more abundant on that record than it's successor VH II and WACF? Some believe Ed used a pedal for the extra gain but he said he was admittedly dead against OD pedals? There was a plugged hole on the back of 12301 by late 78 after that record had been out for a bit?
That plug at the rear remains a mystery huh. But a great plexi down on a variac, biased and then dimed is an amazing thing and has heaps of gain. Put an ep boost or a 10 band graphic in front - it gets you there. Short answer, no I don’t think the amp was modded other than the fat cap and the 50k mid pot.
@@HeadfirstAmps Thanks 🤘
Another rookie question: Where does the red cable attached to pin 1 of the added 4-pin tag board go? I guess somewhere on the bottom of the main board, but where exactly?
what about the SUPER PA? Been thinking on modding my 69(metal plate) super pa 50, having 4 input channels and already having the extra pots and tube....
Great amps
We’ll done videos, subbed. I have this preamp in a floor pedal format with separate paths for the vintage/800 and the Jose circuit. I tried the 20v ZD 16/24v and the trannies, but I think I prefer Red LED’s for the clipper. Seems grainier and smooth with a nice top. Bit more volume drop so I added some series resistance (100k pot) to help dial them in. Have you ever played with LED’s in this circuit?
Cool. Only played with LEDs in Jubilee type circuits.
How close is this to using a Legendary Tones Mod device that goes in the tube slot?
Great video!! I just built my first 50w 2204 from Modulus with the Jake E Lee mods. Question: Why are there caps in parallel on the diodes in this amp? Is it just for more smoothing.
Super neat, love me some basics. Nerd question: Someone once told me that putting the master at the indicator light position can increase noise because it's so close to the power input. Thought on that? Also, I have a feeling that you know a thing or two about setting up a guitar. I just took my two PRS CE-22 from decked to floating and it blew my mind how alive one of them cave. Went from a dull warm mess to an aggressive attacky beast. However, I hate that I can't do double stops any more! If you have any general input on settings up trems, blocking them, etc, that could be a cool video idea in the future.
I guess in theory you could get some interference from the power, however I’ve never experienced it. I think it’s ok.
Floating trems are a whole ballgame to themselves aren’t they. I grew up with a JEM in my hands so I’m comfortable with them….i put one of those tremol-no things on a guitar with a floating bridge to allow it to be locked…worked pretty great.
What are your settings on the test playing .
Is there a schematic for this one?
Only this video guide sorry
+1
I have a jcm800 Kerry king signature head. I was wondering is it possible to put a footswitch on the back so I can turn the beast mode on and off? If your using this amp live you cannot switch to a cleaner sound without clicking the beast mode button off manually.
Hi i have one of these amps. i bought it from the wife of just past husband. and i bleive it to be a 2005 { apparently the first year production}!!! On the Marshall web site it goes into high detail how much effort the put into recreating the original output transformer!!!!!
Long Story Short i basical blew the amp up in the first few test drives!!! Going full rock and roll Full blast and drunk!!!
I beleve my Tech to Be Very Qualifed and expressed that i wanted the MAGIC out put transformer to be supplied by MARSHALL and re installed!! Unfotuantly he ignord my request and said he just contacted Marshall for a 100 Watt output Trans!!
Any opinions would be appreciated!! Even just for a old fassioned Yarn!! Thanks
WOW !!! You nailed it the first time around......now go drive your car into a concrete barrier or something ?
When you do the 68/68k voltage divider, do you still need the 68k on v1 grid? So I see here, but I don't think I see it on the Jose schematic. Maybe i'm not reading it right
I would use 33k not 68k. It’s not necessary, you can try it either way and see what you prefer.
Tone-wise, what is the difference between the Jose mod with the gain stage vs the Jose with Diode clipping?
Diodes add compression and bottom end
It is amazing how a little easy mod like this can change the sound of the amp drastically. Thanks for the overview! Do you think this can be done with the small SV20H too? I have recently got a used one for an amazing price ($500), and I was thinking about modding it.
Totally yes you can. I demo a SV20 that I did the same mod on in a clip a few months ago.
Is that a Kramer 1984 model guitar?
Yeah, the USA one
Thanks for the idea and vid. I have a stock 1959hw from, I think 2021... was the PT Vietnamese or made in England then? Is that a Friedman JEL 100 head I see?
2022 was when the change over happened - I have a video that shows you how to spot the differences.
Hi Jason ....again a great video, thx for all the infos ....fantastic sounding amp ....
i have 2 questions:
Is that mod something similar as a hardwired version of the "Legendary Tones Hot mod" ?
I see that you use a SM57 into the Apollo interface ... do you use a unison Preamp plugin in your Apollo and if yes , which one do you like ... i really like your tones.
Thanks , all the best from Luxembourg , Tosch
Hot mod is just an extra stage at v2 isn’t it? This is not that. This is an extra stage out front, and an added master volume which a hot mod won’t deliver. Unison preamp, yes. Just one of the free UA ones that came with the unit.
Thanks for your reply 👍
what about a parts kit? diagram? for sale?
So when plugged into stock plexi would it act like the high or low input of the stock plexi channel?
Like the high input of a Treble channel.
Is the Hot Mod where you add a dual preamp tube kit to one of the preamp tubes the same as this Jose Mod?
no
@@HeadfirstAmps when I said "the same" I meant does the same thing?
Not the same thing in that it’s in a different place in the circuit, doesn’t add a master volume and will have different interstage dividers. Same as in yeah, it’s an extra gain stage.
@@HeadfirstAmps thank you.
Hi! I am considering doing this mod as my first one... Is there a particular reason not to put the Master Volume pot above the Gain Pot for the added gain stage? Space? Interference? Other? Thanks for looking into my question :)
It’s never a great idea to run a signal that’s at the end of the preamp all the way back to where the input jack is. You can shield etc, but it’s still a bad choice layout wise.
@@HeadfirstAmps Thanks a lot for taking the time to answer this rookie question, mate! I was sure there is a good reason for that, but I was hoping there could be a chance to avoid having to drill the plexi front panel...
No worries. There is also a nostalgic element here, as this is how José himself would do it!
@@HeadfirstAmps Ah, yes :)
Hey Jason love your videos. Question... How does this differ from the hot mod solution?
Hot mod doesn’t give you a master volume does it? And it’s not a stage in front so will sound different.
@@HeadfirstAmps lol... No I didn't mean the master volume part of course... The gain part is what I was referring to. Thanks for answering and keep up the great vids. This one sounds killer!!
Man if you didnt live in oz. Are you gonna put this up mod on your website how much diffrent is this mod then the jose 3 in 1
Videos like this are a public service! Sounds fat bro.
Thanks bro!
Why not put the master control in the rear instead of drilling over the JMP logo?!😠 There's already a predrilled hole next to the speaker jacks.
This is how José did it, and the customer wanted it done this way. Customer wins, it’s his amp.
Just buy JCM800
They need to ditch these trash transformers in their new amps they are noisey and sound weak