How can i add more clarity and definition to a peavay 5150? mods?

[Rod]

Hi everyone!

I have one this peavey 5150 that i like lot, but i would like to mod it to have more clarity and definition?

What electronic components, do you think that i have to change or tweak to achieve this results?

Where can i find schematics for this amp?can you point me the components on the schematic?


Thanks.

[Jazz P Bass]

Well, here is the schematic.

[tedmich]

this guy said he was mocking up a clean kit for the 5150
5150 Clean Mod Kit and Dummy Loads - Ultimate Metal Forum


here's a useful discussion of a DIY 5150 over at sloclone
www.slocloneforums.com | Login

[Chuck H]

I don't think Rod actually wan't the amp "cleaner", just more note separation and definition. Like the Soldono SLO100 kind of sound???

Rod, what kind of speakers are you using? WRT high gainers, and IMHO, the frequency balance is ultra important for THAT sound. Celestion V30 and G12H30 Anniversary's are popular. If your playing a combo model you might like it better through a closed back 4x12. Two V30's and two G12H30 Anni's in a 4x12 is supposed to be THE sound. After that, if all your tubes are strong and correctly biased, you should have enough clarity and definition.

[tedmich]

yah speakers choice can help, as can using lower output pickups...EMG + 5150 = slab-o-flab

lower gain tubes in various positions can help too!

[Gregg]

Consider also modding the preamp as in 5150-II.

[Chuck H]

Isn't that THE sound??? Whenever I hear single note rhythms in modern rock it always sounds bland and flatulent. And all these guys are using Ibenhads with EMG's. I think the modern high gain sound is just too symmetrical and square. As the clipping and gain continue to go up, the dynamics continue to go down. Add to that the modern trend for three and four channel amps that require A LOT of stabilizing circuitry that makes them sound even more bland. Blat blat blat... I must be getting old.

[Rod]

Thanks guys for all your help and support here!

I'm playing this amp with 4x12" with vintage 30, i also have a guitar with emgs, but there is something in this amp that doesn't make i'm sound like a soldano slo.

I have allready made the Bias mod, but did not improved the sound that much.

I have read somewhere that is peavey 5150 amp was based in the soldano slo design, but cheaper production.

Well i would like more note definition,more bottom end tightness, also i want to get rid of some fizz that makes part of this amp.

what do you think about replacing the rectifier diodes?

[Chuck H]

Nothing to be gained tonally by changing the rectifier diodes. If you have access to a guitar with ordinary hot humbuckers you should plug it into your rig just to see if it gives you more of what you want. No rule about using EMG's for modern rock and metal. Worth a try. Other than that you could try a couple of voicing modifications. There is a 39k preamp cathode "cold clipping" stage in there. The cold clipping thing sounds very smoooth. As in, not much bottom end definition. That resistor value would be an extreme example of this. You might get some bottom end definition by changing that resistor to a smaller value like 6.8k. Most of the coupling caps are .022uf. That value offers very little attenuation of bass frequencies as they're overdriven. Reducing one or two coupling cap values might also have the desired result. I know there are 5150 forums out there. I'm sure mods that are specific to your amp can be found. I just don't happen to know any.

[Rod]

Hi again Chuck!

I Will make those resistor and cap mods, and see what i do get.

I'm also looking for the following improvements:

- get rid of harsh highs
- better dynamics
- deep gain structure

What components in the amp circuitry i must change to get these improvements?

I have tryed alot of forums and search for info about DIY mods for this particular amp, and i did get nothing besides the Bias mod, it will be very helpfull to give some ideas on how to improve the sound, because there is a lot of 5150 owners out there.
This discussion and info about mods, can lead the users of this amp to start sharing the results achieved, and maybe reach some solutions to make them happy to give such a good amp a even better tone.

Experience users on designing amps and techs like you will be very helpfull, because they can read this amp circuitry like no one else, and point or give some directions to improve the tone.


Thanks.

Nothing to be gained tonally by changing the rectifier diodes. If you have access to a guitar with ordinary hot humbuckers you should plug it into your rig just to see if it gives you more of what you want. No rule about using EMG's for modern rock and metal. Worth a try. Other than that you could try a couple of voicing modifications. There is a 39k preamp cathode "cold clipping" stage in there. The cold clipping thing sounds very smoooth. As in, not much bottom end definition. That resistor value would be an extreme example of this. You might get some bottom end definition by changing that resistor to a smaller value like 6.8k. Most of the coupling caps are .022uf. That value offers very little attenuation of bass frequencies as they're overdriven. Reducing one or two coupling cap values might also have the desired result. I know there are 5150 forums out there. I'm sure mods that are specific to your amp can be found. I just don't happen to know any.

[Chuck H]

Well... Mods for the gen pop might be limited to easy do's. I've never been inside one of those amps but I read that they're not service friendly.

Dynamics result from not over compressing the tone. Which is sort of the opposite of "deep gain structure" You sort of get one or the other. But certain things do make an amp less dynamic. That cold clipping stage for example. But that circuit is just one part of a very popular cascade design. It's in there because it gives the whole string THAT sound. But it's one place you can experiment. Harshness is caused by many things. Too much bass can even sound harsh if it causes the wrong condition. Usually removal of the "high pass" part of high pass filters and/or increasing the value of, or adding "bleeder" circuits it the course of action. I don't like these methods because they change the signature tone of the amp and deaden harmonics. Sometimes there are other things that can be done. Not always though.

It's your amp. You can experiment with the changes I mentioned and see how it goes if you like. But know that "I" have never done those mods to a 5150. It's only design speculation on my part.

[J M Fahey]

1) It's not a "Soldano built with cheap parts" but a very different project altogether, with an extra gain stage, different voicing, different way to drive the EQ, tons of other differences.
Before butchering it, I'd suggest you try other amps, A Soldano and others, to see beforehand if some other one suits you better.
Could save a lot of frustration !!!
2) some things you complain about are intrinsic to that amp, such as excess gain, not defined enough sound, etc.
This is s Forum full of serious, responsible people who will not send you into fruitless experiments.
ç3) if somebody suggests you "change all caps by *** colored ones" , "wire it with silver wire", "buy 1960 made NOS tubes" and such, run away!!.
It's not a "parts" problem but a design philosophy one.

[Chuck H]

I'm going to second JM's philosophy here and say that this may be a good opportunity to explore and discover what amp works for you!!! If you squander time modding an amp that isn't ideal, as someone who isn't an amp tech or designer, you are wasting time as an artist. Best to find something that works for you and move forward. Unless you're actually interested in designing tone and amps!?!? Very astute observations on JM's part considering that he has chosen to be a builder/designer. I would respect that if I were a player, and not a builder/designer myself.

JM2C

[tedmich]

MANY people out there making a living kludging expensive amps into sounding a LITTLE more like other expensive amps (cough, FJA/Voodoo, cough-cough!) BUT I am with JM on this, sell it and try something different as your resale value is SHOT after heavy modding. If you want to learn amp design on a (fairly) cheap test bed you could try with your 5150 but its a pretty poor choice with its noise/ gain issues and its PCB design IMO. A nice turret board preamp is a better place to feel out amp design, like many over at SLOclone or AX84.

Many of the 5150 mods are very subtle things like tiny silver mica "Miller caps" across preamp tubes to "de-fizz" and silly things like OT/choke "upgrades" and expensive NOS tubes; do run from those as JM suggests!

Have you tried a 6505+? Its an much better designed amp and pretty reasonably priced too! A Sloclone can be made for $600 with judicious parts choices but its jumping into the deep end complexity wise!

[Jazz P Bass]

Well... Mods for the gen pop might be limited to easy do's. I've never been inside one of those amps but I read that they're not service friendly.

Correct me I am wrong, but doesn't the 5150 have that 'U' shaped circuit board arraignment?
If that is true, good luck modding it.