Tube Rolling: Does it Make a Difference?

[ZolaIII]

Instead of messing around with tubes, wouldn't it be simpler if someone just made a preamp that contains the circuit board from a guitar distortion pedal with a dial on the front of the preamp to add the desired amount of distortion / audio corruption to the audio signal?

Instead of accurately labeling the dial as distortion, it could be labeled "Tube Warmth". Same effect.

Maybe Fosi should look into doing that.

In case it isn't obvious, I do not understand why anyone would want to corrupt their audio playback signal with tubes. It seems very counterproductive.

https://www.boss.info/global/products/eband_js-10/specifications/

 

[Brian Hall]

https://www.boss.info/global/products/eband_js-10/specifications/

I'll stick with my current guitar amp and effects boxes / pedals for creating music. I don't want them to have anything to do with my playback systems.

I had several Boss pedals back in the 80s. Still have a working Boss Bass Chorus pedal.

 

[ZolaIII]

I'll stick with my current guitar amp and effects boxes / pedals for creating music. I don't want them to have anything to do with my playback systems.

I had several Boss pedals back in the 80s. Still have a working Boss Bass Chorus pedal.

Well you asked and I shown you that such things exist. There are and fateful VTS copies of late 50's pasive tube (only cuple mV gain) vocal PEQ's and for free who wants that.

 

[egellings]

I'd attribute it to the phrase "rolling your own", which relates to smoking weed.

As required, as required.

 

[egellings]

Does tube rolling mean just substitubeting tubes of the same type, e.g. 12AX7's of different brands, or does it mean using a completely different type numbers, such as a 12AU7 for a 12AX7? Changing type number could be hazardous if doing that causes a destructive runaway oscillation to happen in a power amplifier, as an example.

 

[EERecordist]

A tube subsection of an audio device in this discussion is usually a gain block. The designer biased the tube for linear design or nonlinear artistic reasons. In ASR-type audio gear, hopefully they biased it in the linear range. Almost always there would be negative feedback around that gain stage. That would ensure substituting tubes doesn't change the sound.

Deliberately artistically designed nonlinear gain stages are a different situation.

 

[ta240]

Does tube rolling mean just substitubeting tubes of the same type, e.g. 12AX7's of different brands, or does it mean using a completely different type numbers, such as a 12AU7 for a 12AX7? Changing type number could be hazardous if doing that causes a destructive runaway oscillation to happen in a power amplifier, as an example.

Like many things with tubes, I'm afraid it means what the person saying it wants it to mean. Logically, it would mean different brands of the same number, however a lot of people also 'role' in different numbers that are interchangeable enough to work.

As MattHooper pointed out in a recent post, going with different models of tubes can alter the amp to where it is no longer performing to original specs. In the design of a tube amp the voltage and bias point is selected based on the tube and so is the output transformer. Everything is an integral part of the amp and changing just one part can throw it off.

I've often heard that if you run a tube that is rated to higher output in an amp with lower voltage and bias current you will get the same sound out of it, but just not as much power. Yet, changing the voltage and bias changes where you end up on the curve tracing and thus where you end up with distortion. So you can end up with lower power and higher distortion.
Of course you could end up with an amp that was poorly designed and by changing the model of tube you actually end up with things working better together.

With output transformers there are a wide range of resistance and inductance specs; so even with two amps built to the same schematic you could end up with different performance. Which makes it really difficult when people say "you should try this tube, it sounds great".

 

[ta240]

Poor innocent loudspeakers often fall victim to similar, possibly even well-intentioned, abuse.

That is also one of my favorites. They change a capacitor out for a new one with different resistance and hear a change. Well, you did just alter the crossover.
Or they change an old dried out, failing capacitor for a new expensive one and attribute the improvement to the component being special, not just new and functioning.

 

[DMill]

I have little to add except a word of caution. Flipping tubes that are not spec’d for your device should be very thoughtfully done. There’s a lot of current and nobody wants an obit written about them on trying to sweeten the midrange.

 

[Hipster Doofus]

Thank you, thank you , thank you…I have tubes and have rolled a little with almost no results…it nice to see the charts. Even with tube amps at 36 Sinad and modest SS amps at 80 SINAD and good amps at 110 SINAD, I can barly tell the difference sometimes…so how much less so the difference between individual tubes. At least I tell myself I am starting to hear what a quiet amp sounds like.

 

[musicforcities]

Instead of messing around with tubes, wouldn't it be simpler if someone just made a preamp that contains the circuit board from a guitar distortion pedal with a dial on the front of the preamp to add the desired amount of distortion / audio corruption to the audio signal?

Instead of accurately labeling the dial as distortion, it could be labeled "Tube Warmth". Same effect.

Maybe Fosi should look into doing that.

In case it isn't obvious, I do not understand why anyone would want to corrupt their audio playback signal with tubes. It seems very counterproductive

It’s even easier than using g tubes: just use op amps like bob carver did to “voice” the amp so it “sounds” like any other amp. lol. He had a perverse reason to love blind testing…

Heck some carver preamps (c-4000?) are basically effects boxes…sonic holography anyone? (It worked surprisingly well, btw, as long as you set up the room carefully and did not move your head from a 12” sweet spot)

Want extra tube sound, again, do what carver did and whack a couple huge 1ohm resistors across amp speaker out posts to recreate that tube sound. He called “transfer function” and any of his amps with a T n the model name (TFM, 400t, etc) were “tuned” for tube effect with such things.

Heck, you could just buy a couple 100w resistors and put it between the posts on your existing amp…and see what happens…the amp might blow up. Or maybe the speakers. Or both. Carver stuck
additional fuses in series with those big resistors for a reason.

Fossi could make a preamp “tone box” with selectable op amps. Choose your “voicing” to suit your mood. And they could put resistors on be of the outputs of their VU meter speak we selector box.

 

[musicforcities]

I have little to add except a word of caution. Flipping tubes that are not spec’d for your device should be very thoughtfully done. There’s a lot of current and nobody wants an obit written about them on trying to sweeten the midrange.

Yeah, and 350v even at low amps gives one a real zing if you aren’t careful. Even if you turned the machine off but the caps hold their charge for a bit. Don’t ask.

 

[DMill]

Yeah, and 350v even at low amps gives one a real zing if you aren’t careful. Even if you turned the machine off but the caps hold their charge for a bit. Don’t ask.

I’m glad you’re around to make this post. My grandfather used to have a saying. You make a mistake with plumbing and it costs you a lot of money. You make a mistake with electric and it costs a lot more than that.That said, tube amps are pretty easy to figure out and if you forego large amounts of drinking before tampering with them are quite safe.