Anyone here balancing the triodes on their preamp tubes?

[chameleon2112]

Hi all! Retubing my 50 watt 5153 and I am curious whether any of you have the triodes balanced? Seems like the tube sellers are saying yeah and the guitarists are saying nay. What say you?

 

[glpg80]

As an engineer - it's only needed for the phase inverter. The rest can be unbalanced.

 

[bgh]

As an engineer - it's only needed for the phase inverter. The rest can be unbalanced.

How much of a difference do you see that it makes with the PI?

 

[Ventura]

As an engineer - it's only needed for the phase inverter. The rest can be unbalanced.

True story.

 

[glip22]

In a guitar amp you don't want them balanced. The PI should be but not perfectly balanced. A 6%-10% imbalance is better. This gives the amp better harmonics. I know Allan at Carol Anne uses some very large imbalances in certain slots.

 

[glpg80]

In a guitar amp you don't want them balanced. The PI should be but not perfectly balanced. A 6%-10% imbalance is better. This gives the amp better harmonics. I know Allan at Carol Anne uses some very large imbalances in certain slots.

It isn't that you don't want them balanced, it's that two triodes are contained within an envelope for a 9 pin tube. How each triode is biased and used these days makes the purpose for the preamp needing balanced stages virtually pointless and has no effect on performance.

As far as the PI - it splits one side of the source signal 180 degrees out so that in class AB biased amplifiers, each pair of tubes are amplifying a staggered period of the sinusoid. The bias of the amplifier is controlling the duty cycle for the tubes, the PI controls the phase distribution between them.

6-10% could be the difference between the calibration of the characteristics curve tracer FWIW. Virtually nothing with tubes these days.

Also don't bother with gold plated pins on tubes. The cathode itself is where electrons are being sourced inside the vacuum of the tube. It's smoke and mirrors.

 

[Anonymous]

As an engineer - it's only needed for the phase inverter. The rest can be unbalanced.

Yup - I only used balanced phase inverters in my amps...

Steve

 

[Guitarnobody]

I hardly notice any differences with balanced triodes. I even have a tube tester...so I know exactly what is going into my amps.

 

[crwnedblasphemy]

Yup. PI spot for sure.

 

[blackba]

I usually don't get matched triods and just put the most matched in my pi spot.

 

[just42dave]

been there and done that pi and various 1st or sec gain stage cascading amps,,, but rarely see a diff.. PI is noticeable after awhile and very important to be closely balanced as the guys above nailed it all...

 

[chameleon2112]

Thanks for all the responses! Just had the PI balanced as was suggested.

 

[moltenmetalburn]

PI only, the rest is snake oil as the two halves are independently used elsewhere.

 

[Badronald]

I have tubes in my amp, I turn it on and play.

 

[rottingcorpse]

I have tubes in my amp, I turn it on and play.

I be confuzed. My old randall doesn't have dem thar glass thingys and it seems to work fines.

 

[Stumplegriltskin]

I have tubes in my amp, I turn it on and play.

LO fucking LOL

I'm waiting for someone to break out a fucking graph or some calculations.

Fucking A you guys go deep huh?

 

[IndyWS6]

I have tubes in my amp, I turn it on and play.

LO fucking LOL

I'm waiting for someone to break out a fucking graph or some calculations.

Fucking A you guys go deep huh?

Some of these guys build amps (damn fine amps). "Going deep" is pretty much a prerequisite

 

[thunda]

even balanced phase inverters are not really necessary as many amps only use one side of the phase inverter tube to start with

 

[Badronald]

I have tubes in my amp, I turn it on and play.

LO fucking LOL

I'm waiting for someone to break out a fucking graph or some calculations.

Fucking A you guys go deep huh?

Some of these guys build amps (damn fine amps). "Going deep" is pretty much a prerequisite

Oh I go deep, just not regarding tubes!
Sorry.