lower gain tube in V2

[phsyconoodler]

Does anyone use a lower gain tube in V2?
The reason I'm asking is that in my latest build I am not liking the 12AX7's I've tried.Too much gain and then not enough volume if you turn the trimmer down.Generally not stellar tone.
My thinking is if I use a 12AY7 or 5751 and leave the trimmer high it will smooth it out a bit.
Maybe it's just my playing,I'm liking my Vibrolux overdriven these days.Too much blues at jams maybe.

[talbany]

Nothing wrong with trying a lower gain tube in V2 (Dumble purists can skip this part)..12AY 40% gain in my opinion not enough... little to no sustain notes just die..I have a Telefunkin 12AT I keep in the back of my 70's when I want to get bluesy with it.. At 7s are smoother tighter lows and less of the high end fizz artifacts..Although you can increase the drive/trimmer to try to get it to sing and bloom like an AX it won't.. Still cool.. Give a try..

AT's pull more current so your voltage will drop..

Tony

[ChrisM]

Might want to try some other tweaks first. There are many ODS out there, and many sound just amazing. All use 12AX7 for V2.

[David Root]

How about a 5751 in V2? I tried one in the PI of my #124 and didn't care for it but I didn't try it in V2.

[exocet]

I tried a GE 5751 in V2. It was nice but in reality I just ended up cranking the Gain a little higher to compensate for the fact that this valve (sorry ..tube) only has 70% of the gain of a 12AX7.

[phsyconoodler]

Well I ended up trying another guitar instead.This amp responds to the subtlest nuances.With a guitar that's not set up 100% it has some tones that are funky.With a real nice guitar it shines like the sun.
Wow! What a difference!
My so-so technique was also a factor


It blooms and sustains so long I could have a coffee in-between!

[Structo]

The main thing is to have fun with it.
It can be frustrating sometimes but when you get something right it makes it worth the trouble.

[Max]

Might want to try some other tweaks first. There are many ODS out there, and many sound just amazing. All use 12AX7 for V2.

Not "all":

The ODS 150W I know uses a 7247 for V2. Could sound a bit more marshallesque for my ears if adjusted in this direction. Lots of harmonic richness. If wanted, OD could be adjusted to sound a bit similar to a singing human voice.

With this tube for V2 it made a lot of sense to have Trigger and Taper on the front panel. Lots of different OD voices possible = lots of fun.

Cheers

Max

[jelle]

Might want to try some other tweaks first. There are many ODS out there, and many sound just amazing. All use 12AX7 for V2.

Not "all":

The ODS 150W I know uses a 7247 for V2. Could sound a bit more marshallesque for my ears if adjusted in this direction. Lots of harmonic richness. If wanted, OD could be adjusted to sound a bit similar to a singing human voice.

With this tube for V2 it made a lot of sense to have Trigger and Taper on the front panel. Lots of different OD voices possible = lots of fun.

Cheers

Max

In addition there is an ODS spec'd with 5751's in the preamp.

[talbany]

FWIW.. I just remembered.. Here is a clip of my 70's amp (Posted again) using an RCA 5965 in the OD spot..you'll notice the top end is pretty smooth(less fizz and grit to it) although not synonomous with the blues tone..Keep in mind the 70's w/5965 and the OD pot cranked a bit still retains some of the sustain and bloom a bit better than the later 220K Trimmer/ OD Level setup I've noticed.. I didn't roll many 59's in that spot so it could also be the right tube at the right time..Anyway just goes to show a different tube in that spot has it's place.. Hope this helps..

http://www.soundclick.com/bands/page_so ... ID=8901886


Tony

[Structo]

Nice Tony

I hadn't heard of that tube before but there are many I have not.

The data sheet I looked up said it was a 47 Mu tube and listed it as a "computer tube".

I have an old GE 12AT7 that I had tried before. I didn't seem to notice any difference in gain.
Maybe I'll give it another try.

[talbany]

Nice Tony

I hadn't heard of that tube before but there are many I have not.

The data sheet I looked up said it was a 47 Mu tube and listed it as a "computer tube".

I have an old GE 12AT7 that I had tried before. I didn't seem to notice any difference in gain.
Maybe I'll give it another try.

Thanks Tom

Also keep in mind gain spec by itself is meaningless, even if it is closest to the "real" spec. Just because certian tubes have a mu of 100 doesn't make them any better than another tube that has a mu of 80, because you are ignoring the equally, and perhaps more important, internal plate resistance and transconductance specs. Mu = gm*Rp, so you could have a huge variation in transconductance and plate resistance for the same mu, or gain.

If you tell people that this tube is the one that has the highest "gain", or mu, then they expect it to be the highest gain in circuit, and that is not necessarily the case. The plate resistance has far more impact on tone and actual circuit gain than the gain (mu) of the tube does, when used with "standard" circuit values, because it controls the bandwidth and transient response, in addition to the gain.

Don't confuse gain (mu) with actual gain in real-world circuits. For example, one tube has a gain of 88, and an Rp of 58.8K, while the other one has a gain of 99.9 and an Rp of 83.3K. If you put these into a typical amplifier stage with a plate resistance of 100K, the actual stage gain for the first tube will be 88*100K/(100K+58.8K) = 55.4, and the actual stage gain for the second tube will be 99.9*100K/(100K+ 83.3K) = 54.5.

Not only is the actual gain higher in the tube with lower mu (in some cases), the "real-world" gain is nearly identical. In this case, the internal plate resistance is far more important than the mu of the tube...Tube Geek Talk..


Tony

[Structo]

Thank you for the explanation.

I figured there was more to it than just the mu factor.

The biggest difference I have heard in one of my amps was the little 6V6 amp that was more like a Marshall circuit than anything else at the time.

I tried several lower gain tubes in the PI socket and the results were very obvious.
It cleaned up the amp's tone and had lower overdrive and volume.

So what I took away from that was if the amp is a single channel amp, different tubes in the PI can sometimes be more effective or noticeable than in the preamp.

[talbany]

So what I took away from that was if the amp is a single channel amp, different tubes in the PI can sometimes be more effective or noticeable than in the preamp.

_________________

Definitely

I hope you are feeling better!! Am trying to phase out smoking so if my posts seem moody I apologize!!

Tony

[Structo]

So what I took away from that was if the amp is a single channel amp, different tubes in the PI can sometimes be more effective or noticeable than in the preamp.

_________________

Definitely

I hope you are feeling better!! Am trying to phase out smoking so if my posts seem moody I apologize!!

Tony

Man, you are preaching to the choir on that one.
This is very hard this time to quit.
When I have quit in the past I was always ready to quit and had psychologically prepared myself.
This time was like someone else made the decision.

Good luck on the quitting part Tony.
It's too early for me to recommend the Chantix but there sure are a lot of people that say it works very well for most of them.
It is very expensive if your insurance does not cover it.

But just add up even 6 months worth of cigarettes and which would you rather spend your money on?

OK enough, nothing worse than a reformed smoker or drinker (I'm both).
As one, I know how annoying we can be when we harp on the subject.