Modding 5150 II lead channel to 5150 spec

[JeffTD]

Have I modded an amp for you? I don't recognize the name.
Jerry

I bought from Guitar Center a few years back that had your sticker on it; e-mailed you pictures of the circuit board and you confirmed that it had the bias and clarity mods done to it.

I still stand by my comment though - the 'clarity' mod took away from the grinding top end, low mid roar, and somewhat soulless, sterile (as in EMG's style of 'sterile, soullessness') qualities of the amp that make it ideal for the really brutal, heavy tones we go for in this genre.

For rock of most genres I can see why it would be desired, but for metal? Not so much. I'll take a stock one any day of the week.

 

[ChristianN]

I know this post is almost a year old, but I just found it and...

If someone can come up with making this mod :Shedevil:switchable:Shedevil:, I'LL SEND YOU AN EASTER EGG!

Yeah, detailed schematics, brand of switch and parts etc etc...

Why? I have a 5150 and a 5150II side by side and like both in different ways. I tend to prefer the original one, but some less super heavy stuff sounds better with the 5150II. Also, my riffs sound best on whichever amp I wrote them on...

Mainly, it boils down to want to cut down on having so many damn amps all over the place, and not having to run circles re-plugging in stuff or using amp switchers, and would rather carry around one amp than 2 beasts.

Also, then everyone can stop complaining like, "why the hell did you do that and ruin the sound(?)", cos now you got best of both worlds and you can tell em to shut up.

Oh, and I can't get every sound of my 5150 with the 5150II... I've tried putting in the same exact tubes and switching them back n forth and still no luck. Same cab and everything, as well as the same settings and hours upon days of changing settings.

Such a mod would make me dance! :danceboy:

 

[cellarrodent]

Hello All,

I'm new here, never posted before, and have signed up because of this particular thread topic and how useful I've found it to be. I'd really like to thank everyone for the interaction on this thread, regardless of how old it is! Quick background, old guy just over 50, played through many of amps over the years, lots of influences with my main inspiration being George Lynch, played in some bands in the early days and now too busy with work but still have some fun.

When George Lynch first helped the design of the Peavey XXX, I purchased one of the originals and have really enjoyed playing through it, still my go to amp. When I turned 50 my wife bought me a 5150ii as a present, which was something I wanted to check out and have some fun with. I'll have to admit, I was less than excited with the amp in general, and in comparison to my XXX, not even a close 5th...really. As a result, I was ready to sell this amp immediately, but held on to it based on too much work. Then I thought I might have some fun doing some mods on it to see if I could make it sound any better, and if not...toss it in the trash. I'm serious, my preference and style looks for a big smooth bottom and mid tone with a dynamic and loose/fat/dynamic frequency range...and with great sustain. This thing flat wasn't doing it for me...

So...on to the mod cabinet, and thanks to you guys/gals for helping that out! The first mod I did was the 'bias mod' which helped me get the 'fizz' out. Very simple and I've biased the output tubes to 37mA, which works great for my ear. I also love and use JJ tubes as a personal preference. Still not working for me though...so I continue my search/quest, and find this thread... Great find and interaction...thanks! I start reading through the dialog, find a frequency response diagram done in spice, original designer talking about modding it back to the original 5150, everyone's questions and additions to the mod results, and I'm finally psyched about having some fun tone shaping this amp, to my preferences of course. I'll have to say, while the II has a split eq and better voicing of the clean channel, the original has a so much better voicing for the lead channel, for my ears and genre. Peavey rolled so many of the original lows, and some mids, off the II that it really found it to be neutered and inept...entirely, and in my opinion of course.

Right...so I did the mod today, had some fun doing it, and prepared my ear for the marginal tone changes I'd thought I'd made/face...NOT! The audio clips don't even begin to demonstrate how drastic these changes really are! However, based on how hard the lows were rolled off, I should have realized. Quick end to a long story is, I'm now keeping the amp as it's been resurrected from the 'dead' in my book...massive improvement overall, and according to my taste, ear, genre. Thanks again to everyone, I thought based on the time I'd spent reading and re-reading all your comments, I should at least provide a detailed response and say thanks!

Peace, Rodent

 

[Mago]

^I can totally see why you'd miss some lows from a 5150II, if you're used to a XXX

Thanks for the necro btw, never saw this thread.
I dig the 6505+ tone (tighter and more hi mid focused), but it would be awesome to have it switchable to 6505 specs.
Might have to think about that.

 

[cellarrodent]

^I can totally see why you'd miss some lows from a 5150II, if you're used to a XXX

Thanks for the necro btw, never saw this thread.
I dig the 6505+ tone (tighter and more hi mid focused), but it would be awesome to have it switchable to 6505 specs.
Might have to think about that.

Hey Mago,

You can certainly wire this configuration up with a switch to change the lead channels between the original and II, btw... I listened to the clip on your website, very nice! I don't think you'll lose much of what you've created on this clip, only improve how fat and full the guitar sounds overall. You can still get what you're hearing in the II, but with more low end and slight mids. Unfortunately, you can't go the other direction.

Thanks for the comments on the XXX, and you're right...tough to get away from, at least for my ear. However, I'm playing through the II now about 50% of the time, and really digging the lack of fizz. Up to this point, I've been playing the II through a 4x12 cabinet with older 25 watt greenbacks. On the XXX side, been playing through my 80s ADA cabs loaded with custom celestion 50's, which are my absolute fav's in terms of tone. I've yet to plug my II into them, but will report once I do. Nevertheless, I'm anticipating it just gets better from here. I was all but done with this head prior to the lead mod, so haven't really experimented much thus far.

I'm running 'old school' Lexicon units, G2 & MPX1 in the side chain (effects loop) depending on the day, and nothing in front of the amp (preamp section). Unfortunately really hate all pedals because of noise and 60 cycle hum... Admit I always did, even as a teen in the late 70s. A boost, like a Keely modded DS-1 or older TubeScrm works with the II, but nothing works in front of the XXX, based on the amount of gain, at least in my opinion. I still own a great deal of rack gear, and continue to enjoy the delay, chorus, reverb, and compression of my lexicon units.

Type soon...Peace!

Rodent


Thanks again for the reply and conversation!

 

[cellarrodent]

Sorry Mago,

here's a song from the 80s, recorded in the early 90s, using an older 4100 series JCM900 Marshall, a 21 pro for compression in front of the amp, and an MPX1 in the side chain for delay, running through the 25 watt greenback cab I still have: Satisfied...put your 'old school' cap on for a minute please! This is of course, to show you where I'm heading in terms of tone, which I very easily get from both Peavey amps now, and provide you with a reference for my music/style as you've done.

Peace, Rodent

 

[Melb_shredder]

Got my 6505+ bias modded and installed Winged C tubes in the power section... Absolutely destroys the tone I was getting prior. I think it's a great mod to do

 

[amarshism]

whats the high and low inputs for on the non +
Ive always used the high but yesterday tried the other one and i prefer it

 

[NecroDM]

whats the high and low inputs for on the non +
Ive always used the high but yesterday tried the other one and i prefer it

Just like the name implies, the high gain input will have more gain than the regular input. Not that you'll need more gain though, unless you plan on using the rhythm channel for metal riffs.
Personally I'd rather use the normal input and lead channel as it's tighter than the rhythm and use the rhythm with low pre-gain for a clean-ish sound if needed.

 

[eddiewarlock]

i am gonna necro bump this again. I find this VEEEEEEERY interesting. I had a 6505 which i loved to death, anyways, i now have a 5150 II bought it used but mint, the thing looks brand new, based on the opinion of a friend who's had it and the original 5150 and he told me both amps sounded the same. Not to me. I miss the aggression the original one has. On tuesday i had talked to a guy into trading his 6505 for my 5150 II then i find this thread and start having second thoughts. If i mod it, then i will call the trade off, i will look like an ass, but i know my amp, his, i don't. Tomorrow i will go to this shop in Seville ( Spain) thatmakes amplifiers and repair marshall and engl amps, and see if they know what do to. I guess they should.

 

[Alphakhronos]

Again I'd like to bump this thread. So much useful info. I'm actually thinking of modding my 5150 voicing to be closer to a 5150II. I was thinking of making it switchable but with a pot instead of a switch so i can blend between the two sounds and find a sweet spot. I'd probably make it an internal pot rather than having it on the front, so set it a bit more permanently after deciding where to set it.

 

[Danny Cook]

Keep in mind the 2nd one isn't showing the best tone with the mod. It's showing how drastically different it is with the same EQ settings.

As for whether the "C" clip is too hairy - that's a matter of taste. I prefer the sound of the original 5150 - and according to the schematics these components are the only differences between the lead channel on the two amps. The clean channel is completely different (and is better on the 5150-II) so you're getting the best of both worlds with the mod. Again, that's as far as my ears are concerned.

I'm pretty sure the Peavey parts sheet calls for 400V capacitors, but I don't recall if the resistor was 1/4 watt or 1/2 watt. I happened to use some big old capacitors because that's what I was able to get from the old dude in town who works on amps. As you can see in the pics there is plenty of room to work on the main board. The preamp tube board is a little tighter, but I was still able to cram a huge capacitor onto it.

I'd also like to mention that the cap & resistor on the main board do not represent a shining moment in my soldering career. I did it quick & dirty just to see if I liked it and figured I'd clean it up later if I kept it that way. As it stands, that was the last time I had the amp apart until today. Since it works and I've gigged with it I see no reason to fuck around with it.

Also, I didn't reduce the resolution on these photos so they are pretty huge.

Main board. Changes circled in yellow. Legs of the original capacitor are circled in red:
http://www.ryanadam.com/5150/IMG_0532.JPG

Main board from further back to get a better idea of where it's located:
http://www.ryanadam.com/5150/IMG_0533.JPG

Pre-amp tube board from above. New cap is circled in yellow:
http://www.ryanadam.com/5150/IMG_0534.JPG

Peavey layout with location of C17 marked:
http://www.ryanadam.com/5150/IMG_0536.JPG

Peavey layout with location of C2 marked:
http://www.ryanadam.com/5150/IMG_0537.JPG

The only other mod I've done to my 5150:
http://www.ryanadam.com/5150/IMG_0540.JPG

Same shot, but with the flash which obscures the fact that the whole panel lights up:
http://www.ryanadam.com/5150/IMG_0539.JPG

If you want to check out some solder work I'm less ashamed of, check out the Metal Panel JMP 50 clone I just put together:
http://www.guitar-hardware.com/ampkit/IMG_0517.

Maybe you could elaborate on what each one does to the amp I’m interested for sure