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

[rbasaria]

FWIW, I was just talking about pre tube labeling....like which tube is V1, which is V2, etc....

Ive only tried different brands of 12ax7 tubes in the pre. I really dont have any complaints, so I never went to different tube types...

 

[xiwiwix]

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.

Agg! Maybe because I haven't slept in 20 hours and I feel like a zombie at this point; and I was out side because the cable guy was here fixing my problems with the internet. (I hope that made sense)


What I did:
I dropped in hotter power tubes removed the Tung Sol from V1 and replaced it with a lower gain 7025, removed the tubes with no names from V4 and V5 and replaced them with Tung Sols's.


Ok so where my amp stands:
It sounds stiffer and cleaner. Notes are more pronounced and the amp has a way more aggressive feel to it after all the tubes have been rearranged as I posted a few posts back. It sounds way CLEAR-ER than before.

 

[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."

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)

Ah, yes! The 12DW7 pre amp tube. That's the pre amp tube I've been wanting to try but I haven't come across one yet. Alas I'm VERY happy at the moment and I think the next step is to mod this bad ma'am jamma! Hopefully Jerry will be able to pimp out this bass ass!

I'm really loving my amp, so much that my ears are ringing right now.

 

[MOAAH]

FWIW, I was just talking about pre tube labeling....like which tube is V1, which is V2, etc....

Ive only tried different brands of 12ax7 tubes in the pre. I really dont have any complaints, so I never went to different tube types...

The closest tube to the input is pretty much almost always called V1!
I think I may have seen one once, in 40 years, that the schematic listed otherwise.
Then each tube corresponds to how far away from the power tubes.
The rectifier, if present, would be the last.

 

[Bob Savage]

The closest tube to the input is pretty much almost always called V1!
I think I may have seen one once, in 40 years, that the schematic listed otherwise.
Then each tube corresponds to how far away from the power tubes.
The rectifier, if present, would be the last.

You can have all the rules you want to, but I call the preamp tube closest to the input "Skippy."

 

[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.

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.

Yes I agree about the preamp section, but the power tubes actually have 3 possible settings.
One where the crossover distortion is minimal, it is considered ideal.
And either, too hot or too cold.

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.

They all vary the tone, how substantially depends on the design.
Yes 500V is crazy high, ain't it 470 on the schematic?
Yes extra sag related to lack of a choke, which is all I was tryin' to relay

 

[MOAAH]

The closest tube to the input is pretty much almost always called V1!
I think I may have seen one once, in 40 years, that the schematic listed otherwise.
Then each tube corresponds to how far away from the power tubes.
The rectifier, if present, would be the last.

You can have all the rules you want to, but I call the preamp tube closest to the input "Skippy."

You are BOB, I am rob.
LOL

 

[Mailman1971]

The closest tube to the input is pretty much almost always called V1!
I think I may have seen one once, in 40 years, that the schematic listed otherwise.
Then each tube corresponds to how far away from the power tubes.
The rectifier, if present, would be the last.

You can have all the rules you want to, but I call the preamp tube closest to the input "Skippy."

Skippy? well thats strange.......
I call mine closest to the input "Sweet tits Malone"....
has a nice ring to it.

 

[xiwiwix]

Honestly, I can't fucking wait to see the A-Team movies! They better make B.A. a big ass pussy like Ms. T was when it came to certain things. I remember them always having to knock him out to get him on a plane. lol! RAMPAGE!

 

[JerryP]

The tubes are labeled out as follows:
V1, V2, V5, V3, V4 that's going from the input jack to the power tubes.
V1, V2, & V5 are all gain stages
V3 is the effects loop send and return
V4 is the phase inverter

The signal goes thru half of V1 to the gain pots, then the other half of V1, then thru V2 & V5, then thru the EQ and the master volumes, then thru half of V3 out the loop send, back in the return to the other half of V3, and onto the PI V4.
Jerry

 

[xiwiwix]

The tubes are labeled out as follows:
V1, V2, V5, V3, V4 that's going from the input jack to the power tubes.
V1, V2, & V5 are all gain stages
V3 is the effects loop send and return
V4 is the phase inverter

The signal goes thru half of V1 to the gain pots, then the other half of V1, then thru V2 & V5, then thru the EQ and the master volumes, then thru half of V3 out the loop send, back in the return to the other half of V3, and onto the PI V4.
Jerry

I think I'm gonna move my 7025's to V2 and V5 and put my RFT in V1.

 

[gbsmusic]

Quick question. I'm going to use a 2nd cab. Can I just plud in a 2nd 16ohm cab? I dont see a switch anywhere to set it to 8. Thanks!!

 

[Roland]

Quick question. I'm going to use a 2nd cab. Can I just plud in a 2nd 16ohm cab? I dont see a switch anywhere to set it to 8. Thanks!!

Yes, and only a 16ohm cab. Sucks huh?