Peavey 5150 Combo pre amp tube layout's and GT's Rating 9's

[xiwiwix]

If you guys have a 5150 Combo here's some info for ya.

I just got off the phone with Peavey, and here is the pre amp tube info. This goes from Right to left with V5 closest to the power tubes.

v1
(a)before pots all channels lead and clean
(b)after pots

v2
(a and b) gain

v3
(a)bass treb mids
(b)post gains

v4
(a)send and return
(b)pi

v5
(a)phase inverter


If anyone has anymore info please let me know so I can update it. The gentleman helping me was reading it off of some hand written paper; I'm guessing some one asked him about it not too long ago.




I also just dropped some GT's Rating 9's (6L6-B) in my little monster and wow! Huge difference! You can feel the tubes cooking; kind of like my old Marshall JCM 800 2203 2x12 combo. The bias is up, I can smell it.

Way more dynamic, it uncompressed a little and the clean got cleaner. YES! Woohoo!!! The gain isn't as mushy either. I wouldn't say there's less gain but I had to bump up the gain knobs on both channels to get to what I had with GT's Rating 6's (6L6-R). It roars a lot more and the tone sound smoother, not so brittle.

I really think with the mod I asked Jerry (FJAmods.com) about I'm going to be in tone heaven within a few months.

 

[Dale B]

The only problem with GT 9's is that they will burn out quicker because they're over spec'd power tubes. The GT 6 area is considered to be "normal" specs.

Also, the bias on a 5150 combo is already up there pretty close to where it needs to be. There is no choke in the amp, so what you're mainly hearing and feeling is the extra compression of those hotter power tubes. The power section compresses further and runs cleaner. You lose a lot of dynamics when you run hotter tubes like that, yet it may not be such a bad thing from a feel standpoint with the lack of a choke.

Weird huh?

 

[Bob Savage]

Whoah! Where have you been kiwi?

 

[Dale B]

I thought the same thing too, Bob. LOL!

 

[Bob Savage]

I thought the same thing too, Bob. LOL!

No doubt. You can't be MIA for as long as he has and just come barging in here with a post as if you never left.

 

[MOAAH]

There is no choke in the amp, so what you're mainly hearing and feeling is the extra compression of those hotter power tubes. The power section compresses further and runs cleaner. You lose a lot of dynamics when you run hotter tubes like that, yet it may not be such a bad thing from a feel standpoint with the lack of a choke.

Weird huh?

I've never heard of anyone stating that a choke adds compression. A choke is a huge improvement over a cheap resistor, but that would be in filtering out unwanted AC ripple which in turn can improve noise, headroom and clarity. A choke is not needed from this standpoint in any of the modern amps using electronic regulation and I have used both. They seem great for modern tone and cleans, but neither is good IMO for old style power tube distortion, which results from power supply sag.
YMMV.

 

[rbasaria]

Nice. I love my 6505 combo. Ive been given so much differing info about the tube slots that its hard to believe what any one says about them. Ive even had 2 different people at Peavey tell me 2 different things....

 

[MOAAH]

Ive even had 2 different people at Peavey tell me 2 different things....

Most manufactured amps use a cold bias setting stock and Peavey from my experience is not the exception, but pretty much the worst case example. This is to help insure that the power tubes last as long as the initial warranty. So anyone looking for more power tube sound will likely benefit from hotter running tubes. However, the 5150 and the like were designed primarily for preamp distortion, hence the crazy amount of cascading preamp tubes.

 

[Dale B]

There is no choke in the amp, so what you're mainly hearing and feeling is the extra compression of those hotter power tubes. The power section compresses further and runs cleaner. You lose a lot of dynamics when you run hotter tubes like that, yet it may not be such a bad thing from a feel standpoint with the lack of a choke.

Weird huh?

I've never heard of anyone stating that a choke adds compression. A choke is a huge improvement over a cheap resistor, but that would be in filtering out unwanted AC ripple which in turn can improve noise, headroom and clarity. A choke is not needed from this standpoint in any of the modern amps using electronic regulation and I have used both. They seem great for modern tone and cleans, but neither is good IMO for old style power tube distortion, which results from power supply sag.
YMMV.

You didn't see me write that a choke adds compression either did you? "There is no choke in the amp, so what you're mainly hearing and feeling is the extra compression of those hotter power tubes."

You don't need to school me on the uses of chokes and resistors.

 

[xiwiwix]

I thought the same thing too, Bob. LOL!

No doubt. You can't be MIA for as long as he has and just come barging in here with a post as if you never left.

Ha! Hey guy's! After I stopped whore gear I kinda disconnected from the internet. lol!

I'm glad you guy's are still up and running!

Dale,

Yeah, that is kind of weird. So you're saying there's more compression? The amp feels like it opened up, notes are jumping off my fret board like never before, and now all the mushy gain is gone. So getting hotter tubes doesn't compensate for the colder bias?

 

[xiwiwix]

Nice. I love my 6505 combo. Ive been given so much differing info about the tube slots that its hard to believe what any one says about them. Ive even had 2 different people at Peavey tell me 2 different things....

I hear ya bro and that's why I called Peavey. So I'm guessing this is their latest info or something. The guy had it in writing and was reading it to me. Who know's, and if they do, they should chime in.

 

[xiwiwix]

Ive even had 2 different people at Peavey tell me 2 different things....

Most manufactured amps use a cold bias setting stock and Peavey from my experience is not the exception, but pretty much the worst case example. This is to help insure that the power tubes last as long as the initial warranty. So anyone looking for more power tube sound will likely benefit from hotter running tubes. However, the 5150 and the like were designed primarily for preamp distortion, hence the crazy amount of cascading preamp tubes.

But doesn't colder tubes mean thinner harsher sound? That's one of the difference I heard between both sets of tubes.

 

[xiwiwix]

Nice. I love my 6505 combo. Ive been given so much differing info about the tube slots that its hard to believe what any one says about them. Ive even had 2 different people at Peavey tell me 2 different things....

Have you tried any different pre amp tube?

I have a 12AT7 and a 12AU7A, where should I put them so I can tame the lead channel gain? I don't want to mess with the clean channel. Which Slot affects which channel is my question.

 

[xiwiwix]

My tubes

V1 Tung Sol
V2 Solvtek 7025 12AX7WA
V3 RFT
V4 and V5 are two unmarked tubes.

I'm about to drop the 12AT7 and the 12AU7A in and see which work best "where."

 

[MOAAH]

You don't need to school me on the uses of chokes and resistors.

I may have been misdirected by you mentioning the use of a choke in relation to compression.
I just thought I'd clear it up for anyone else seeing the same, nothing personal and no offense intended.

 

[MOAAH]

Ive even had 2 different people at Peavey tell me 2 different things....

Most manufactured amps use a cold bias setting stock and Peavey from my experience is not the exception, but pretty much the worst case example. This is to help insure that the power tubes last as long as the initial warranty. So anyone looking for more power tube sound will likely benefit from hotter running tubes. However, the 5150 and the like were designed primarily for preamp distortion, hence the crazy amount of cascading preamp tubes.

But doesn't colder tubes mean thinner harsher sound? That's one of the difference I heard between both sets of tubes.

Yes, that is what I was trying to say in your quote, sorry if there was any misunderstanding. If you run tubes that need less bias(i.e., hotter running tubes) to get them going, then you are actually compensating for the colder bias of a stock amp.

 

[xiwiwix]

Ok so now my Pre amp tubes are

V1 Solvtek 7025 12AX7WA
V2 Solvtek 7025 12AX7WA
V3 RFT
V4 Tung Sol
V5 Tung Sol

Wow! The note are now even clearer, the clean is punchy-er and the gain is more aggressive sounding. The Gain knob doesn't act so much like a basss knob now. It was acting weird; if I lowered the gain the bottom end would leave as well. Those unmarked tubes were sucking some of the clarity out of my tone.

This sucker is now one of my top 5 amps!

 

[MOAAH]

So getting hotter tubes doesn't compensate for the colder bias?

No, that is exactly what they do. Again they need less to get them going so yes the hotter running tubes compensate for a colder bias.

 

[Dale B]

So getting hotter tubes doesn't compensate for the colder bias?

No, that is exactly what they do. Again they need less to get them going so yes the hotter running tubes compensate for a colder bias.

It compensates for it in how the circuit is performing. Tonally? Well, not so much. It depends on whether or not you want a cleaner sounding and stiffer feeling power section. If you have a lower gained preamp and you want more dynamics, hot tubes like that aren't favorable.

It gets to be an apples and oranges thing. In this amp it probably isn't such a bad thing because the 5150's preamp section is almost falling all over itself (that's why it's loaded down after the 3rd gain stage) and there is extra sag because of the lack of a choke. The plates of the power tubes are seeing right at 500 vdc, but that doesn't carry much weight in regard to overall tightness because of the way the circuit is designed.

 

[Mustaine-who?]

My tubes

V1 Tung Sol
V2 Solvtek 7025 12AX7WA
V3 RFT
V4 and V5 are two unmarked tubes.

I'm about to drop the 12AT7 and the 12AU7A in and see which work best "where."

You'll probably want to start in V2. That should have the most effect on lowering the gain, but also making your gain sweep broader and more useable. I changed V2 in my XXX, and holy god really made a nice big difference in the quality of the gain, and being able to tweak it to where I want it. Tho I didn't use a a 12AT or AU7...I used a 12DW7, which "One side has a gain factor of 100 - the other side has a gain factor of 20. You can think of it as 1/2 a 12AU7 and 1/2 a 12AX7." (The tubedepot.com)