Phase inverter v5,, does it change sound at all?

[recto-robbie]

Hello everyone, I was wondering if anyone knows if changing tubes in the phase inverter position v5 of my stiletto deuce for example will actually change the sound at all,, darker tube= darker sound
bright tube= brighter sound.

Any help at all is appreciated,,, thanks, Rob

 

[CaughtLikeFire]

Hello everyone, I was wondering if anyone knows if changing tubes in the phase inverter position v5 of my stiletto deuce for example will actually change the sound at all,, darker tube= darker sound
bright tube= brighter sound.

Any help at all is appreciated,,, thanks, Rob

no, not in that way. if your current phase inverter tube is poorly balanced and/or has low current, you'll notice a difference by putting in a balanced tube with high output (1.2ma+). smoother distortion and lack of fretboard "deadspots" are a few possible results of putting in a better PI tube. The PI is not part of the tone generating stages so dark/bright characteristics of a particular tube have no effect.

 

[lyman]

it won't make as much of a difference compared to changing tubes in the V1 position. which in turn, doesn't make as much of a difference as switching speakers. so in other words, maybe a very slight difference depending on how different tube A is from tube B.

in my amp, i swapped the phase inverter from a 12ax7 to a 12at7 and did notice a subtle difference. felt like there was more headroom, or maybe the power section stayed cleaner when i turned up the output higher. no difference in tone, just in response/feel.

fwiw, i have tried balanced and unbalanced tubes in that spot and never noticed any difference. in theory it might matter but for "real world" purposes there's much more important factors in getting a good tone.

 

[recto-robbie]

Thanks for the help above, I have always had a balanced
tung-sol 12ax7 in the PI position. I guess whatever its doing,, its doing it fine. Im trying to find additional ways of darkening my deuce when I play alone. I refuse to swap out speakers in my 4 month old boogie traditional 4x12. And I love the way it sounds when I play in a mix.
Just trying different things to tame the highs a bit when playing alone.
Funny thing is, ive got plenty of ways of doing this but still find myself intrigued on finding more ways. Weird HUH?

 

[lyman]

Im trying to find additional ways of darkening my deuce

try more iron in your diet.

 

[jtb226]

hahaha.


What difference would putting a 12at7 in the PI do? I'm still learning tubes as well.

 

[stokes]

A 12AT7 has less gain than a 12AX7 and doesnt drive the power tubes as hard.A balnced PI dont mean squat in a guitar amp.The components in your amp,including the PI circuit are +/- 5 to 10% or more tolerance,so even with a balanced PI tube by the time your signal gets out to the power tubes it aint balnced no more.Balanced PI's are more useful in Hi-Fi applications where the components tolerances are tighter and the users are looking for super clean undistorted sound repro,guitar players dont want or need those kind of cleans.Recto-Robbie,to darken up or smooth out your tone,try a NOS 5751 in V1 or the PI position or both.Real smooth sounding tube.I can almost guarantee you will be happy with the tone.Almost every Boogie amp that has come across my bench has left with at least one 5751 in it,or the owner has left swearing he was gonna get one.

 

[recto-robbie]

Whoa,, good info there stokes. So if I add a 5751 to the phase inverter position,, theres a chance it will actually help the tone?

And if I add one to v1,,, will this decrease the amount of available gain?


Thanks for the help stokes and all

 

[stokes]

If it "helps" the tone is subjective.It will change it,albeit not as drastically as the earlier stages,but everything in your signal chain affects the tone,even the PI.My observations are different from lymans.When I sub a 12AT7 and AX7 in the PI I see a big difference,I'm not saying lyman is wrong,but tone is totally subjective,what is apparent to some is not to others.An AX7 has an amplification factor of 100 while the AT7 is 60,so the AT7 doesnt drive the power tubes as hard,which will affect your tone,as it alters the parameters your power tubes deal with the signal,so to say the PI doesnt affect the tone of an amp is wrong,it wont be as drastic as changes made earlier in the preamp would be,but everything in the amp affects the tone to some degree.The 2 tubes also have different output impedence,which will affect the tone as well.The 5751 has slightly less gain than an AX7 and rounds up the tone very nicely.It is much more apparent in the V1 position.It does reduce the gain somewhat,but more noticeably rounds or smooths or darkens the tone,however you may want to describe it.I would suggest trying it in V1 first for the most noticeable effect,but definately try it in each and if you can get 2,try them in both at the same time and even experiment in all positions.I have about 15 or so amps,including 2 Boogies and I have a 5751 in the V1 position of all but one amp,which has a 12AY7,even less gain than any of the tubes already mentioned.Get yourself a couple and have fun,you wont be dissapointed.

 

[recto-robbie]

Thanks again stokes,, ill get a couple for sure.

 

[lyman]

good posts, stokes. since adding my .02 to the mix i've had a chance to try out my amp with some other guitars and pedals and at various volumes. it's helped to give me a better perspective. i think the difference in tone is more significant than what i first thought. brighter and not as fat, which could definitely be the sound of the el84's not getting pushed as much. i have to do more playing/listening and tube rolling. it's fun stuff!

 

[212Mavguy]

+100 for the comments of stokes...

Also, a well used preamp tube will sound darker for a given type than a brand new one. As far as 5751's go, I know sixveesix really enjoys the GE triple mica blackplate, I enjoy the Tung Sol, and Raytheon 5751, with or without the windmill getter. Vintage old stock tubes are particularly addictive to those susceptible tone junkie types, watch out! :wink:

 

[recto-robbie]

tell me about it,,, I cant say that all my previous current production tubes are bad but I will say that ive finally opened my wallet and bought my first NOS tubes. This past weekend, I heard sounds come out of my amp ive never heard before. Honestly.

 

[stokes]

tell me about it,,, I cant say that all my previous current production tubes are bad but I will say that ive finally opened my wallet and bought my first NOS tubes. This past weekend, I heard sounds come out of my amp ive never heard before. Honestly.

Its just the beggining.Be prepared to open your wallet again and again......Like Mav says,it is an addiction.The more you hear what NOS tubes will do for your tone the less you will speak so kindly of those current production tubes you have.

 

[phyrexia]

tell me about it,,, I cant say that all my previous current production tubes are bad but I will say that ive finally opened my wallet and bought my first NOS tubes. This past weekend, I heard sounds come out of my amp ive never heard before. Honestly.

Its just the beggining.Be prepared to open your wallet again and again......Like Mav says,it is an addiction.The more you hear what NOS tubes will do for your tone the less you will speak so kindly of those current production tubes you have.

I wish I had never swapped my first 12AX7. :twisted: 8)

 

[recto-robbie]

Well I will agree with you guys now. I am going to have to watch it because ive been down the raod of an endless open wallet looking for amps then pedals.
Just last week I picked up a couple NOS 12ax7,s and immediatly noticed a great improvement,, I swear ive never had an amp including my current setup produce such awsome sounds.
Needless to say I took the advice of a couple of you guys and purchased some NOS 5751's. All I did is add 1 to v3 and 1 to v5 the PI,, alongside the nos 12ax7's in v1 and v2. And again it was even better.
Im going to have to swap them around to see what actually did what though. I should have taken my time and added just one tube at a time.
I did notice after adding the 5751's that it seemed like my gain decreased but then realized that the gain was there,, I just had to raise the level on my gain knob. The 5751's have less gain than the 12ax7's but to my ears, not much less. I also noticed less uncontrollable feedback after adding the 5751's.
Again im going to have to spend some time with mixing and swapping them all around to see what the best order is and to understand how the circuit reacts with different combos.
And I wont be speaking so highly of my current production tubes anymore.
Thats for sure. I know its true but I still cant get over the fact that these current tube makers cant make tubes like they used to.
I must have 7 or 8 different types of current 12ax7's and not a one of them is on par with my first NOS 12ax7.