Truly Fantastic Tube Phono Kit - For Beginners?

dowto1000

Junior Member
Dowto1000,

I haven’t tried using two resistors in parallel as a gridstopper. I’ll put that on my list for investigation, but it’s a long list.

I wasn't thinking grid stoppers, I try not to ever use grid stoppers, now a days.

But,as one example I know of, where the paralleled and closely matched Rs shine is for an Ra and a Rk, both positions of the same tube. I parallel in 90% of my build locations, on the vacuum tube Ra and Rk in particular. It gives two equal paths, is more dynamic, better sounding, quieter, and plain ole FUN to hear !! The very best place to try this initially is on the Plate Resistor, of an early input stage. Bump it up on your priority list !! :-)

The MFA manufacturers ( of a friend's Luminescences, plural ) were using 2 Watt Cornings on something like a 12AX7, and went to parallel Cornings, matched very closely, several decades ago.

Dowto1000
 
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Alexz

Junior Member
AlexZ,

One more question, if I may. It would be helpful to also know what were you using for the two RIAA caps in each channel, prior to switching to air variables?

Type and brand, if you recall it?

TIA!!

Dowto1000

Not sure about the brand, they were NOS non-magnetic silvered mica in epoxy.
 

Alexz

Junior Member
@Alexz
Thanks for correction.

I hadn't read that summary and don't follow the site but, some years back, I saw that Romy was using Soviet surplus vacuum caps. A ham friend told me about it and I went to have a look. Nuts!

Air variables are certainly more "practical" than vacuum caps, so I can't blame him for switching over. For one thing, the wiring of a vacuum cap array would be troublesome, to say the least. So much for 1" connections!

That would surely be worth a try, I'd have to agree. Few RIAA circuits use low enough C values for such monkeyshines, so the 834 is a good test bed for this experiment.

i went Ruskie surplus on my RIAA but I used modest silver micas of prewar Siemens design. Can't fit anything bigger in the target chassis.

View attachment 5410

A 250pf vacuum variable is shown for size comparison.

View attachment 5411

well... would be nice to build photo stage inside 250p cap. Thanks for sharing.
 

dowto1000

Junior Member
Not sure about the brand, they were NOS non-magnetic silvered mica in epoxy.


Thank you !! This tells me, you did have decent caps in there to start, and so, it becomes more meaningful to discover that your replacements are even better.

Alex, I have been wanting to build a tube RIAA preamp, for a LONG time, and you, and this Hi Fi Haven thread, has given me a direction, I intuitively was looking for, for at least a decade ! At this juncture, I am very happy.

Thanks to all who contributed.

Dowto1000
 

Alexz

Junior Member
@dowto1000 ... In the mid 1980s, I was able to hear tenths of an ohm, on DHT ( 6B4G ) grid stoppers, which were in the 115 Ohm range. Yes, that was audible to me...

That is an intersting topic. Im not trying to dispute that it is posible to hear 0.1ohm difference in grid stopper value, or 0.01g VTF or 0.001dg VTA or whatever
I just not buying the actual benefit of all that. We are not listenin to some abstract super precision signal, we are listening to a music recorded via chain of mic amp., console, rec amp., repro amp., cutting head amp etc. Somewere in between in most cases was also chain of mastering equipment. I’m pretty sure no one in EMI, Decca, RCA etc. who design and setup all this equipment give a flying f@#$ (am i violating forum rules ?) about 0.1 ohm grid stoppers.
I think (again, just my opinion) all this is an another attempt to put measurable value to subjective evaluation. For example, RIAA has 0.001% precision components. OK, great, but are there any recordings with 0.001% accurate EQ ? It’s just a numbers, the same thing as 70s 0.0000001% THD or 0-10mhz bandwidth.
 

prime minister

Site Owner
Staff member
@dowto1000 ... In the mid 1980s, I was able to hear tenths of an ohm, on DHT ( 6B4G ) grid stoppers, which were in the 115 Ohm range. Yes, that was audible to me...

That is an intersting topic. Im not trying to dispute that it is posible to hear 0.1ohm difference in grid stopper value, or 0.01g VTF or 0.001dg VTA or whatever
I just not buying the actual benefit of all that. We are not listenin to some abstract super precision signal, we are listening to a music recorded via chain of mic amp., console, rec amp., repro amp., cutting head amp etc. Somewere in between in most cases was also chain of mastering equipment. I’m pretty sure no one in EMI, Decca, RCA etc. who design and setup all this equipment give a flying f@#$ (am i violating forum rules ?) about 0.1 ohm grid stoppers.
I think (again, just my opinion) all this is an another attempt to put measurable value to subjective evaluation. For example, RIAA has 0.001% precision components. OK, great, but are there any recordings with 0.001% accurate EQ ? It’s just a numbers, the same thing as 70s 0.0000001% THD or 0-10mhz bandwidth.

Wow.
Great post!!!
 

dowto1000

Junior Member
Alex,

You state this :

" I’m pretty sure no one in EMI, Decca, RCA etc. who design and setup all this equipment give a flying f@#$ (am i violating forum rules ?) about 0.1 ohm grid stoppers.
I think (again, just my opinion) all this is an another attempt to put measurable value to subjective evaluation. "

- - - - -

Personally, when I did that 1980's - Ohmic value bracketing / listening - by - ear work, I did not consider, ( and nor do I care even today ) about what the EEs and Techs who made the LPs did.

Nor, back then, was I trying to be " an advocate of subjective evaluation ."

All I wanted then ( and now ) was to build as good-a-sounding DHT amp, as I possibly could, within my means.

Have fun. I do.

Best wishes and Cheers.

Dowto1000
 
How do you know that you were hearing the ohmic value and not the various physical attributes of individual resistors?

You can't.

Even among units of same manufacturing lot, are they perfectly identical?

Was every solder joint or binding post connection EXACTLY the same?

Moreover, you changed every time you did a trial. Each time, each cycle, you had more experience under your belt and perhaps different expectations, based on that accumulated experience.

Your moods changed, fatigue and fascination intervene, the vinyl wore and the plastic deformed through various replays, the noise on the AC line changed, the barometric pressure and humidity, and hence the actions of sound in air, changed.

And on and on...

Yeah this is all piddling detail, but so is the very idea of auditioning 0.1 ohm variances in grid resistors. In fact, the whole excercise is made of details, slippery little buggers at that.

The knowledge conditions of this exercise do not allow for any certainty. There are no controls, no stability in the context.

I'm pretty sure that the human flake factor far outweighs the electrical significance of a 0.1ohm change in a grid resistor. That's just how we are and it is neither consciously apparent nor negotiable.

I tell you, as soon as aesthetic listening by human subjects begins, secure knowledge ends, every time...but especially in whacked-out micro auditioning programs.

So, as Frank Zappa put it, "Who you jivin with that cosmik debris?"

Naive audio forum objectivism is equally unfounded, for many of the same human variability reasons, plus more. The underlying logical positivist model underpinning this sort of brute science was discredited and abandoned by the 1930s.

Look at it this way, even in physics, Einstein's Relativity taught us that there is no perch from which to become a universal objective observer, that's why it is called relativity!

Two (or more) knowledge systems collide in audio and none wins. It is actually a very complex situation if taken seriously, with a somewhat-technical understanding of epistemological conditions underlying this activity. It is more anthropology than engineering, but engineering is anthropology too from where I sit.

Man has no other way to engage the world except through invisible cultural lenses and filters applied to an ongoing flow of unique historical events.

I am agnostic on others' listening experiences and preferences, do my own evaluation in my own natural use contexts, and maybe I'm learning something while getting progressively more confused and less inclined to decide for anybody else. This feels right to me and does not conflict with my book learnin'. :grandpa:

Or perhaps I should say my educational indoctrination...but it is what I am.

Y'all can go out and get as freaky as you wanna be...as long as I don't have to watch or hear the moans and groans through the wall.

In any case, i would be careful about yanking grid stoppers on high gm VHF tubes because it is an empirically-verifiable fact that such amplifiers can very easily go into mad oscillation on Channel 6, with unknown effects on AF performance.

At VHF frequencies, heater lines are feedback loops, 1/2" cap leads become tuned LC circuits, stray reactances and unintended coupling create a parallel world, and you can't apprehend this underworld with ears.
 

mhardy6647

Señor Member
So -- wait --
There's a parallel world underneath the hood of my amplifier...?

oh, wow, man...


In seriousness, though -- yes (and FWIW), I agree (with @J-ROB's comments above). His observatios illuminate exactly what makes hifi a fun hobby for a guy who's made his living as an analytical scientist.

Well -- that and the opportunity to listen to and to be moved by wonderful music.
 
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dowto1000

Junior Member
J-Rob,

Your acceptance, or non-acceptance, of my report from that mid 1980s build, today in 2018, or even back then, is not of importance to me. I did the work, I heard it, for myself. Your post above, and what ever others want to conclude, is fine with me !!

I am impressed with a few of those words you mustered-up in the post above. Wow. I am also appreciative for what you did by publishing Sound Practices. That was a fine breath of fresh air, when it existed !!

J-ROB, try this one thing, on your new point-to-point 834 build :

For the plate resistor of the very first tube, V1, also listen to two times the Ra value, with the pairs of Rs paralleled and matched at 0.01% or better, to each other ( to avoid skews ), and report back, what, if anything, you hear. If on a budget, order from M. Percy ten pieces of 665K Roederstein MK-3s, from which you will get 2 close-enough matched pairs, at a $2.50 cost for all 10 Rs.

Alexz ...... could try it also. Just listen to that. Suggest doing this using MK-3s !!

This excercise may get tube builders moving in a positive way.

Have fun, and thank you for taking the time to comment.

Dowto1000
 
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Alexz

Junior Member
@dowto1000 .... Alexz ...... could try it also. Just listen to that. Suggest doing this using MK-3s !!

Thank you for the recommendations, I really appreciate all the good intentions. The only missing part , IMO is to ask me what my objectives are and is "paralleled and matched at 0.01% " anode load resistors anyhow is in the path to archiving whatever I think is important to me in music reproduction and appreciation.
 
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Your acceptance, or non-acceptance, of my report from that mid 1980s build, today in 2018, or even back then, is not of importance to me. I did the work, I heard it, for myself. Your post above, and what ever others want to conclude, is fine with me !!


It doesn't matter whether or not I question it. What I suggest is that you question it.

Other people's listening experience are not in my world, but mine are. You are the only person for whom those 80s experiments have any relevance and at this point they are distant memories of experiences. How do you know if that matters anymore to you today?

Experiments are cool but the parts are only a piece of the experiment. Your brain, ears, experiences, whole life situation at the time of testing is the other part of the test.

Are you the same person you were in the 80s. Is your hearing the same? Have you learned nothing in 30 years? How is what happened in the 80s valid and relevant to you today?

These are important questions to ask.

The first person I know who advocated multiple parallel resistors was Pierre Sprey of Mapleshade, a famous and very skilled micro-auditioner. He brought a preamp into the store where I worked in the 80s with paralleled resistors all over.

But he used THREE parallel resistors, Big 2 Watt brown IRC RN spec metal films, I think I remember. Why are you stopping at two? Wouldn't three (or ten) be better? How do you know?

To me, the whole house of cards of audio evaluation is shaky by nature. Any claims to truth are highly conditional and those conditions evaporate soon after, or maybe even during, the test.

What makes tests work as tests is that they are separate and apart from ordinary listening experience. Comparing and listening super hard, with furrowed brow, trying to pick up on nano details...this is not normal listening.

The question is does the findings of the test have any relevance to day-to-day casual listening and, if so, what is it?
And how do you know that?

All in all, there is not much absolute certainty to be had in audio evaluation. It is a loose process of fitting complex systems of equipment to even more complex and ever-changing, unique human listeners.

I often ask myself how I am knowing something. Often the answer is that I don't really know it, but I'm just acting as though I know it.

An old sociological maxim worth keeping in mind is "What man believes to be true is true in its consequences."

Such is the human condition. This is why we need music.
 
J-ROB said:

"All in all, there is not much absolute certainty to be had in audio evaluation. It is a loose process of fitting complex systems of equipment to even more complex and ever-changing, unique human listeners.

I often ask myself how I am knowing something. Often the answer is that I don't really know it, but I'm just acting as though I know it."


Very nicely put! I wish I had said that myself.
 

Alexz

Junior Member
115278C8-2B32-4C4D-B4C2-BB743020472F.jpeg 4B3541FA-BB46-4377-8F02-18803FB15ECE.jpeg basicaly 7308 mu follower direct to 600r S&B LCR capacitor to D3A (now, thanks to @Salectric i have to try to use current source to load D3A). A bit crazy choke input mercury rectifier all film cap’s PS
 

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prime minister

Site Owner
Staff member
What the pictures don't clearly illustrate is the beauty and sheer professionalism of Alex's work. I've seen gear in high end audio stores that doesn't look as good. Or sound as good!
 
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