How to install BIAS MOD in PEAVEY BUTCHER + Full recap and maintenance tips + Audio review
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- Опубліковано 21 кві 2020
- A Peavey Butcher came in the shop that needed repair. To give this amp a new lease at life all of the electrolytic caps were replaced, installed new output tubes, installed adjustable bias circuitry and installed a better output jack system than the counterintuitive one that comes stock.
Fast forward to the end to hear the amp through Celestion G12T-75's and Vintage 30's mic'd with an SM57
The adjustable bias was achieved by swapping R52 on the power board (470-ohm stock) with a 3K resistor and replacing R53 (47k stock value) with a 10K resistor in series with a 22K mini potentiometer with the wiper and opposite fixed end soldered to the large ground pad on the underside of the PCB.
This is, hands down, my favorite Peavey amp I've heard so far. I really like the simplicity of the design and it was super easy to work on. I think these were very well made and stand the test of time. After all, the circuit design in the preamp is almost identical to a Marshall 2203/2204 circuit.
Enjoy and happy riffing! - Навчання та стиль
Man It makes me happy to see your excitement over this amp. I’ve had my butcher for probably 10 years now and I love it. It’s the one amp I’ve owned that I’ll never get rid of
I would never have guessed these amps didn't have a bias adjustment built into them. That seems like a pretty decent design flaw. That was a clean fix/mod.
I'm not sure why they didn't have this as a feature. Would have been easy enough to implement without raising the cost.
And that's how you'll find all the original survivor amps, still working just fine. At one point, the 6L6 tubes being put in these were of a superior quality to anything else available at the time or even since then. These original Peavey branded tubes of certain lot numbers are even more highly sought after than these amps themselves. I would have to go back and re-read the guys post, but a lot of former and current Peavey employees are in Peavey CVLT FB group. Look for Derrick as an admin as there is a copy cat group as well. The Butcher rabbit hole goes deep!!
I had a VTM60 head ... killer . Basically the Butcher with factory added mod switches that did wonderful things for tone . Marshalls got all the glory ... but these Peaveys really have some solids guts .... and killer tone . I'm snaggin next one I find
Metal Zone in front was a nice combo. A Marshall Governor or TS would really make it sing
Get a Marshall Shredmaster pedal
Those series 1 Butchers are MONSTERS!! I would crank it up and hit that stadium E major and literally dim the lights in the whole house! Lol
I just had a customer drop off a Butcher last weekend, and i did the same mod for the bias as yourself. It's astonishing how heavy the cabinet is!
Ive been consuming your content for the past couple of days and as a fellow amp addict and aficionado I can see your love for this stuff. I appreciate your care,attention to detail, and mostly your sheer reverence for the original circuit. I'm of the opinion that we have so many amp options as guitarists these days why molest a classic when you can get a modern production unit that is identical with the mods already installed? And you end it on "Rock Forever" by Priest. \mm/
Great job, man, awesome video! Love the care and attention to detail.
Great video, and great job. Very fun to watch. Best part is the no disclaimer on discharging caps... very metal. :-)
i have owned 3 peavey supreme 160 amps and regret gettin rid of the last two i will not trade my newest one in those amps are awesome peavey just makes stunning amps built like tanks they will last forever and sound awesome .
Just had a Supreme 160 given to me that the previous owner had plugged his power amp into the preamp in..¢.86 later and I have my early 90's Grindcore amp in house again.
Dude reminds me of Dimebag for some reason and is as talented in amp repair and mods as Dime was in the fretboard! Awesome video on an awesome amp! Sounds amazing! Lots of balls. The tone and volume coming out of it raises testosterone levels!
I was thinking the same thing, Dime would have for sure loved this guy.
Dude. So glad I found this channel. I love the content. Hopefully you keep it coming, as this has become my favorite channel. Also, if you're able to answer a few questions for me when you have some free time, it would be greatly appreciated. Thanks for the awesome channel man, totally made 2020 not a complete shit ass year.
Love that ya left in the audio with you're little one, reminded me of times where my little girl has come in when recording.
Hey my friend, I've been playing 2 VTM60 stacks since they came out in 1988 and it's like they were made for Boss SD1 on a medium gain setting, BUT if run clean it turns a MetalZone into a Soldano!
I'm pretty stoked too for your love of the Butcher! I bought one brand new in '86. Had it for a bit and let it go. Now I own two of them. :) Great video man. I really enjoy all of you postings and appreciate how you describe the process as you're working and most of all, you do it the right way. Great job!
Any chance you could do a video on how to safely test for power and discharge a tube amp before working on it? Thanks!
Awesome content man rock on
Great vid man! You'll really flip your lid when you get a VTM60 or 120 on the bench (butcher with an effects loop and dip switches). I'm in the middle of recapping a VTM120 that i've had since new. I've been on the fence about adding the bias mod but I think you pushed me over the edge!
Hells yeah, I LOVE the sound of these... Awesome that I know who you is enslaved by Homey... This is your channel? *subbed*
That thing sounds absolutely killer
Awesome guitar man!
I knew a dude who had one of these in the 80s and it sounded better than my Marshall plexi. Absolute beast, better gain, lots of punch, and louder. It totally drowned out my Marshall.
KILLER ON THE LOOSE!
a lady killer!
Your a cool dude, and your daughter was adorable....new subscriber man...
Leaving the leads soldered into the board for filter cap replacement is actually a good idea because it makes for not only easier recapping, but less damaging to the pcb every time they need done. But nice work tho. Love these old Butcher amps.
one f the years had a 5th speaker tap that was the 120w 44v tap, i imagine you would need a transformer to use that on, any ways great vid and cool mod. sorry for the multiple comments was spouting off as I was watching. Now onto the FX
loop video
How do I send you my Butcher head? I've had it for 35 years, so don't want to sell it. I just want YOU to mod it. You are a rare talent and a genius of a man. Thank you for sharing your brilliance.
I'd be happy to work on it for you. I am uploading another video where I've installed an FX loop in one of these amps for another customer and it sounds killer. I found one for sale locally and I bought it with the intent of doing some modifications to make the amp growl some more and really beef up the low end to make the amp punchier and tighter. Drop me a line at purgasoundamps@gmail.com
I seen one of those butchers at a pawn shop a couple of days ago for $300 , I might grab it for the right $$ just cause , after watching your vid. It is in excellent condition just looked like it's been sittin on the shelf since the 80's collecting dust. 🤔
Do it dude. 80s Peavey amps are insanely good for their price. I've got a butcher and a Peavey Windsor both I got for around 500$ combined
1st is 16, 2nd opens the 8 ohm tap for use of 1st and 2nd at 8ohm , the 3rd opens the 4ohm tap, if you run 2 8ohm loads you would use tap 3 and 4.
I run 4 16ohm 412s on mine no problemo. It's a beast
Was that one riff from a Diamond Head tune? If not it was remarkably similar. Maybe some Saxon in there too?
30:29 Good cut! I own a couple custom shop deans and when you tap the head on something.....Swear word Tsunami incoming!
Adding a nfb resonance mod makes a big difference. Other than that a few gain stage mods can help if done right. Modded a ton of those over the yrs ( along with about every peavey ever made)
got the special130 heritage,Butcher,vtm120,Ultra120,Windsor and my beloved 6505+ had to make a choice 5150 or 6505+ the 6505 has a bit more edge,and a crunch section for clean chanell to play the classics.
I need the schematic for the power cord,I fixed the board and got it running great,somebody dropped the head down the stairs it was so heavy and ripped out the cord,but I no longer have a schematic to wire power cord.
I think you're supposed to bias the 6L6GC tubes on these amps as if they are 25 watt tubes. I've always found about 1mA below the 70% calculation sounds pretty slammin' on these heads when using a 25 watt calculation. People that like more clean headroom I usually go about 1mA over 60%.
The reasoning behind that is the higher plate voltage that hits the plates in combination with the spec of the output transformer only requires you to bias the tubes as if they are 25 watts each. Biasing them as if they are 30 watt tubes will over-saturate the OT at high volume, the tubes will run hotter than they should, so that = less lifespan and the amp will also begin to sound splattier and not as tight when the power tubes reach over-driven levels.
This was a common problem I saw with a lot of owners of Marshall heads that came equipped with 6550 tubes. They would bring their amps to techs who would bias the tubes at their rated 35 watt spec and then people would blow their speakers, because the amps were putting out way more power than they were designed to. At the factory Marshall was biasing the 6550 tubes as if they were 25 watt EL34 tubes, since the iron in the amp was designed for them.
The Peavey Butcher OT was designed for 25 watt 5881 tubes, so the correct calculation for a 30 watt rated 6L6GC would be 25 watts at no more than 70% of plate dissipation to stay within spec of the amp design.
VTM 120 is the same amp with all dip switches off, James Browns 1st amp, the amp that became the 5150, same power section
Hey man, where ya at? Ive got a VTM Id love to have you work on.
hey i have an old peavey standard 260 thats melting speakers and has a very quiet output. The capacitors tested okay but they are the originals making them 40 years old. They held a charge for over a day after being powered off. should they be replaced or is it a transformer issue? thanks for any help
Hey Brent, how much electrical/electronic experience do you have, and how much would you recommend to get into amp troubleshooting/modding/building. I know that some knowledge is required so you don't fry yourself, but do you need to be an electrician to work on these?
How do you think a bass would sound through it?
Can you recommend a good amp tech in Washington state east side or in Post falls Idaho !?
Would that bias mod work the same for a VTM?
Is that a peavey Ultra Plus to your right on that box ? Had my Ultra Plus 120 Modified almost the same. But different Tubes.
I think around that time I had a JSX and a 5150 in for repair. I haven't seen an Ultra in a long time. Would be really cool to work on one soon. (famous last words)
@@purgasound I have the expert Mod specs done on mine if your interested.
the butcher, vtm60 and vtm120 all had the same output jack setup. i think peavey did it that way because 1/4" jacks are really cheap when you buy them in a huge quantity and they didn't want to buy selector switches just for these amps..
I pawned mine and after I picked it back up the serial numbers didn't match. I wonder if that was mine. I kept good care of it when I owned it. The one I got had road use. I didn't have a chance to check it out moving 700 miles away. I don't think I picked it up from the pawn shop, and had someone else pick it up. I have the amp in storage now. Covid made a long move for me, and if Indiana didn't steal my unemployment, I'd be better off. I have to fix all the controls on the front, because they were scratchy when I got the unwanted replacement. If I stop by my storage I'll try to find my paperwork and get the serial number.
I cut my teeth on that amp and yes an overdrive makes it scream . I played a lot of dokken back then had a lot of kids thinking that amp was the secret to that tone lol. Hope they figured it out. They probably designed some of it crazy because it was so close to another popular amp they may have been trying to cover their ass. Idk. Think they got sued anyways and had to stop making them. I was able to save money and buy one. I can’t say that about the other brands.
But the peavey went through hell in my teenage days. I sold it after it fell off a truck been in the rain and everything. If i had and honest tech around i would probably still have it. ..I assumed it just had it and easily replaceable like all the other stuff I’ve sold. A lot of people didn’t like peavey amps back then. Regardless Peavey sure made tough reliable amps in the 80s I had some of the combos up until recently and they were still going strong
i can buy one tomorrow for $450 Canadian...and it came from and was modded(2 switches..1st switch is up for boost, down for more boost, 2nd switch is for Eq, up for range, down for focus) by Richard at Airis effects! what you think, if i get it, you interested Brent? its a late 80s 120 watt. and super cool and greta shape! Matt.
I am not looking for one at the moment but that sounds like a good deal!
@@purgasound yea not bad. ever thought about doing one on the Marshall 'mode four' 350 watt head? that'd be interesting to see. ..(there's one in a pawn shop here in Toronto for $500CDN, thinking about it, see why Alex Skolnick says it is the best Marshall head ever built! ha Cheers
Did I hear a Mentors riff? ;)
I have one of these for sale in excellent working order. Let me know if your interested.
made in the USA.
Some Peaveys are self biasing.
I have an original butcher if you are interested in it? I will let it go.
bahahahahahaha, no shit the case is tank
Remember people this is an amp tech, you cannot just go opening your amp and touching things inside without blowing off a finger or worse, like tube tvs ok. You have to know what you are doing. And how things work in an amplifier and be trained.