Different Tube Positions.

Jethro Rocker

Jethro Rocker

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Just curious about changing out pre amp tubes in various positions.
I have rolled tubes for a few years now. I realize the importance of quieter tubes in V1 amd the cascading of gain and the like. I have improved the tone of some of my amps in this way.

What I question are the other positions, like, reverb driver and loop or PI. Do these have any real effect on tonality? I have an RFT in V1 on my big Jubilee for eaxample but is it a waste to have a nice old Raytheon long black plate in PI position? Same with some of the simpler designs like the JCM800 series, 4010 amd the new SC20H.
Does it overly matter which tubes I might use in a cathode follower or EQ section etc?

Cheers
 
Jethro Rocker said:
Just curious about changing out pre amp tubes in various positions.
I have rolled tubes for a few years now. I realize the importance of quieter tubes in V1 amd the cascading of gain and the like. I have improved the tone of some of my amps in this way.

What I question are the other positions, like, reverb driver and loop or PI. Do these have any real effect on tonality? I have an RFT in V1 on my big Jubilee for eaxample but is it a waste to have a nice old Raytheon long black plate in PI position? Same with some of the simpler designs like the JCM800 series, 4010 amd the new SC20H.
Does it overly matter which tubes I might use in a cathode follower or EQ section etc?

Cheers
Click to expand...
I honestly could never hear great tone differences outside of v1 or v2 if it was a 4 or more preamp tube amp. The reverb and phase inverter sections? I couldnt tell much differences honestly. I do know some amps use a 12AT7 as a reverb tube or a phase inverter vs a 12AX7 stock but anymore, a 12ax7 down the line seems to be the standard.

V1 however is where experimenting can actually get slightly different tones, nothing overly drastic though. I use a 12Au7 in my JCM2000 DSL50 in V1 and it chokes back a lot of the gain to give it a more natural headroom sound. It will get similar sounds in V2 as well but i like the V1 better
 
Clockworkmike said:
I honestly could never hear great tone differences outside of v1 or v2 if it was a 4 or more preamp tube amp. The reverb and phase inverter sections? I couldnt tell much differences honestly. I do know some amps use a 12AT7 as a reverb tube or a phase inverter vs a 12AX7 stock but anymore, a 12ax7 down the line seems to be the standard.

V1 however is where experimenting can actually get slightly different tones, nothing overly drastic though. I use a 12Au7 in my JCM2000 DSL50 in V1 and it chokes back a lot of the gain to give it a more natural headroom sound. It will get similar sounds in V2 as well but i like the V1 better
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Yeah V1 I have good results with the old Mullards in some of the Marshalls. Others like higher gain Chjnese tubes, like the 6101. RFTs sound good too.
Subtle differences to be sure although a Mullard in V1 in the TSL tamed some shrill highs. I wonder about the PI tube when the amp is up near full.
 
Jethro Rocker said:
Yeah V1 I have good results with the old Mullards in some of the Marshalls. Others like higher gain Chjnese tubes, like the 6101. RFTs sound good too.
Subtle differences to be sure although a Mullard in V1 in the TSL tamed some shrill highs. I wonder about the PI tube when the amp is up near full.
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Ive heard others say that V1 and Phase Inverter give the best tone differences in their experience, so maybe youre onto something about trying it at a higher volume setting! Trying it at a bedroom level for me? Never heard much change, but i didnt think to crank it up so maybe that WOULD have changed the dynamics
 
Jethro Rocker said:
Bedroom, no. But once the power section is pushed, even in 5 watt mode on the minis, the PI tube is overdriving. I mean, I guess I could just try it. As for the other spots, seems pointless using nice old tubes i those positions.
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Yeah thats worth a shot in trying it definitely! I think the biggest waste definitely is if you swap them in a reverb position on any amp, v2 is arguably a waste too since V1 is your primary gain stage and would change the most dynamics
 
Clockworkmike said:
Yeah thats worth a shot in trying it definitely! I think the biggest waste definitely is if you swap them in a reverb position on any amp, v2 is arguably a waste too since V1 is your primary gain stage and would change the most dynamics
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I agree I think although some amps cascade V1 to V2a or even both sides of V2 and in that case, I think one would find a difference as well with V2. In the 800s it is only V1 I believe for the gain stages.
 
Cadorman said:
The only improvement for a reverb or loop driver would be using a super quiet non-micrphonic tube in those positions as far as I can see. I would use current production for those. My DSL1HR really likes the vintage stuff. I think I'm running a Sylvania 12au7 for power and GE 5751 and 12AX7 in V1 and V2.
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Ok that's what logic told me but wasn't sure. I had some RFTs and Raytheons amd the like in some loop drivers etc which seems wasteful. I have heard and do have some microphonic ones in PI slots successfully.
 
Jethro Rocker said:
Just curious about changing out pre amp tubes in various positions.
I have rolled tubes for a few years now. I realize the importance of quieter tubes in V1 amd the cascading of gain and the like. I have improved the tone of some of my amps in this way.

What I question are the other positions, like, reverb driver and loop or PI. Do these have any real effect on tonality? I have an RFT in V1 on my big Jubilee for eaxample but is it a waste to have a nice old Raytheon long black plate in PI position? Same with some of the simpler designs like the JCM800 series, 4010 amd the new SC20H.
Does it overly matter which tubes I might use in a cathode follower or EQ section etc?

Cheers
Click to expand...
The tubes can make a night and day difference but at very low loudness you may not hear it all.
You might want to save the best tubes for recording....
Like for example, a Sino 12AX7 can sound like a preamp on steroids compared to a low sensitivity tube....
Traditionally 12AT7 has been used as a reverb driver, it's going to be cleaner than a 12AX7.

As far as "NOS" tubes or "old used" tubes etc. that's subjective.
In repairs I never sell "NOS" tubes or "old used" because they cause too many problems.

I always fear that some goofball is going to plug an old shorted tube in, and fry the transformer etc...
Because they think the old tube makes the amp sound "vintage."
 
Amp Mad Scientist said:
The tubes can make a night and day difference but at very low loudness you may not hear it all.
You might want to save the best tubes for recording....
Like for example, a Sino 12AX7 can sound like a preamp on steroids compared to a low sensitivity tube....
Traditionally 12AT7 has been used as a reverb driver, it's going to be cleaner than a 12AX7.

As far as "NOS" tubes or "old used" tubes etc. that's subjective.
In repairs I never sell "NOS" tubes or "old used" because they cause too many problems.

I always fear that some goofball is going to plug an old shorted tube in, and fry the transformer etc...
Because they think the old tube makes the amp sound "vintage."
Click to expand...
So a 12AT7 won't affect output or such when used as a reverb driver, for example?
All my old tubes were tested and came from very reputable sources. I find they are smoother sounding really are nice in most of my Marshalls. Built to last!
 
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