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Old 9th April 2004, 10:18 PM   #21
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Default Components......

BTW: Where can I get the following?

22uF/250v
220uF/450v
47uF/250v
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Old 10th April 2004, 11:14 AM   #22
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Default Re: Components......

Konnichiwa,

Quote:
Originally posted by jazzpeter65
1. Would a regulated solid state PSU give a better signal-to-noise ratio?
Unlikely. As shown the whole PSU filtering will give << 0.1uV RMS PSU noise and in essence 1/2 that on the output of the SRPP. Compared to a 2V RMS output for digital full scale you then have theoretically -146db for PSU line noise, the Valves themselves will produce a lot more noise, solid state power supply regulators usually produce a lot more noise than valves, so better stick to simple & predictable passive filtering.

Quote:
Originally posted by jazzpeter65
2. PSU: Can I substitute the special resistors for normal ones?
Which "special" resistors.

Quote:
Originally posted by jazzpeter65
3. What do I have to change to use E80CC or 12Bb4H?
The pinout needs to be accounted for etc, you may wish to adjust the cathode resistors in the SRPP Stage.

Quote:
Originally posted by jazzpeter65
BTW: Where can I get the following?

22uF/250v
220uF/450v
47uF/250v
At any decently sorted component supplier.

Sayonara
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Old 10th April 2004, 11:45 AM   #23
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Hello Thorsten,
I have a question about the PSU for your tube output stage: the 210V at its output is supposedly taken with the load of 2 tubes, right?

I am a total newbie, what's the idle current of these stages (so I can calculate the PS component values with PSU designer?

Can be the 22uF capacitor connected to the pin 1 if ECC88 be electrolytic (maybe bypassed with a MKP) ?

Thank you

Andrea
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Old 10th April 2004, 02:14 PM   #24
Ryssen is offline Ryssen  Sweden
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I am going to try this one on my Brute force headphone amp,and even on the DAC tube stage if it works out right,I am going to build 2 of them one for each chanel as the cost is not so high,will there be any difference compared to one in chanel separation.
I am not so good at counting the values of components,Instead I build and try and ask people here who knows,but Im learning.


I am going to use different zeners for a lower output voltage
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Old 11th April 2004, 08:27 AM   #25
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Default help on some of the components for the DAC outputstage..

Sayonara,

From what I can read in your latest answer there is no nedd for a regulated PSU - I'll just stick with the one you have designed.

Before start building the DAC outputstage I need your help on some of the components:

1. By "special" resistors I mean Holco, carbon composite non-inductive resistors etc. Can I use standard resistors instead and what sonic differens will it make?

2. What are the names of the "drop-in" equivalent tubes that can substitute ECC88? Some Russian tubes maybe?

3. Like Andrea in this thread, I've found that the 22uF/400V Ansar supersound metalised polypropylen you mention is hard to get. Where can I get it? And isnt 22uf an extreamly high (non-standard) value for a propylen cap? Is there a substitute for it? (Farnell or RS number)

4. I'm wondering about the two polystyren caps: 0,012uF and 0,12uF. Must be 12nF and 120nF, right? These values are not standard. Do you have Farnell or RS numbers on them?

Best,

Peter
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Old 11th April 2004, 11:37 AM   #26
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Default Re: help on some of the components for the DAC outputstage..

Konnichiwa,

Quote:
Originally posted by jazzpeter65
1. By "special" resistors I mean Holco, carbon composite non-inductive resistors etc. Can I use standard resistors instead and what sonic differens will it make?
First, carbon composite and Holco ARE "standard" resistors. Secondly, especially in the Powersupply the use of non-inductive resistors is fairly important.

Quote:
Originally posted by jazzpeter65
2. What are the names of the "drop-in" equivalent tubes that can substitute ECC88? Some Russian tubes maybe?
With the SRPP as shown you merely need one switch to adjust the heater connections and you can use any of the following Valves and their equivalents (use TDSL at duncanamps.com for full equivalent listings):

12AT7, 12AU7, 12AV7, 12AX7, 12AY7, 6DJ8, 6922, 6CG7 and any of their direct and near equivalents.

Quote:
Originally posted by jazzpeter65
3. Like Andrea in this thread, I've found that the 22uF/400V Ansar supersound metalised polypropylen you mention is hard to get.

I find them supremely easy to get:

www.cricklewoodelectronics.com

Quote:
Originally posted by jazzpeter65
And isnt 22uf an extreamly high (non-standard) value for a propylen cap?

Well, I know off hand of at least five or six locally (UK) available Manufatcurers who have Polypropylene capacitors in such values readiluy and fairly inexpensively (compared to premium grade "audiophile" electrolytic capacitors), Ansar (UK), ICW (UK), SCR/Solen (FR), Arcotronics (IT), Ducati (IT). All these companies make polypropylene capacitors up to around 50..60uF.

Quote:
Originally posted by jazzpeter65
Is there a substitute for it? (Farnell or RS number)
Sure, plenty. Just look it up.

Quote:
Originally posted by jazzpeter65
4. I'm wondering about the two polystyren caps: 0,012uF and 0,12uF. Must be 12nF and 120nF, right?
Yes, 0.12uF = 120nF. ANd sorry, but these Values ARE standard or can be made up from standard values by paralleling.

Quote:
Originally posted by jazzpeter65
Do you have Farnell or RS numbers on them?
Please look them up yourself, you must appreciate that I have not got the time to go through catalogues for you.

Sayonara
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Old 11th April 2004, 01:35 PM   #27
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Default Ahem....

Hi,

Quote:
With the SRPP as shown you merely need one switch to adjust the heater connections and you can use any of the following Valves and their equivalents (use TDSL at duncanamps.com for full equivalent listings):
Quote:
12AT7, 12AU7, 12AV7, 12AX7, 12AY7, 6DJ8, 6922, 6CG7 and any of their direct and near equivalents.
May I hope you're not going to make them believe they can just pop those in?

12xx7 most adhere to the Jedec 9A standard.
6DJ8 and equivalents adhere to Jedec 9AJ which is a totally different pinout.

To be pin to pin compatible is one thing, to work is another and to work optimally is yet another story still.

As for equivalents of the ECC88/6DJ8, yes the listing at Duncan amps gives you a fair idea.

USRR nearest equivalent of the E88CC/6922 is the Sovtek branded 6922 or 6H23-P-EB.
Although marketed by Svetlana as such, the 6N1P is NOT equivalent to the ECC88.

Ideally an SRPP stage works best with a pre-known load and a stiff as a brick PS.
If not you'll notice the soundstage becoming a foggy blur.

Cheers,
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Old 11th April 2004, 10:40 PM   #28
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Default Re: Ahem....

Konnichiwa,

Quote:
Originally posted by fdegrove
May I hope you're not going to make them believe they can just pop those in?
Asolutely, if you use the circuit discussed and observe the following note in my original post:

"you merely need one switch to adjust the heater connections"

Quote:
Originally posted by fdegrove
12xx7 most adhere to the Jedec 9A standard.
6DJ8 and equivalents adhere to Jedec 9AJ which is a totally different pinout.
Actually, in all relevant areas the pinout is identical. You need to connect pin9 (heater centertap on 9A and shield on 9AJ) to the negative heater voltage and pin 4 to the positive heatervoltage. For 9A pinout pin 5 is switched to the positive heater voltage, for 9AJ to negative heater voltage. Works absolutely great.

Quote:
Originally posted by fdegrove
To be pin to pin compatible is one thing, to work is another and to work optimally is yet another story still.
The SRPP is a fairly special case and as shown a wide range of Valves can be used, if neccesary with a slight adjustment of the cathode resistors. I originally designed this stage to abel to work with a wide range of Valves on purpose, hence the Biasing is not the absolutely ideal case for 6DJ8/6922.

Quote:
Originally posted by fdegrove
Although marketed by Svetlana as such, the 6N1P is NOT equivalent to the ECC88.
No, it is actually workable in most ECC88 circuits though and usually more linear.

Quote:
Originally posted by fdegrove
Ideally an SRPP stage works best with a pre-known load and a stiff as a brick PS.
That is the orthodox view.

I found that theroeticaly "ideal" and "good sound" do not always go hand in hand. I appreciate the work of Mr. Broskie, but I do not make the mistake to take his proof of ideal harmonic cancellation into a given fixed load asproof of "good sound".

Quote:
Originally posted by fdegrove
If not you'll notice the soundstage becoming a foggy blur.
I have failed to notice that, sorry. It actually sounds more likely that something, somewhere was slewing, given your description.

Sayonara
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Old 11th April 2004, 11:13 PM   #29
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Hi,

Quote:
I appreciate the work of Mr. Broskie, but I do not make the mistake to take his proof of ideal harmonic cancellation into a given fixed load asproof of "good sound".
So do I but that theory is still correct and is extremely logical in its approach.

If you care to cross check, Jean Hiraga and our Japanese friends who original brought the circuit back to our attention showed exactly the same.
Looking at Hiragas' SRPP phono stage you can't possibly miss the gigantic PS.

Add to that the fact that almost all SRPP circuits ideally require separate envelopes for the triodes allowing each to have its heater biased up to cathode potential and you'll see why I'm not all that convinced by this drop in a tube and forget about it thing.

Unless you want to drive them all bananas, that is...

Take it as you like but I've dabbled with SRPPs of all kinds over the passed twenty years and with all kinds of tubes and whatever the theory of operation, facts are still facts and SRPP circuits certainly are no exception to the rules.

Other than that they certainly can sound fine.
I wouldn't have bothered with them for so many years if they didn't, or would I?

Cheers,
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Frank
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Old 12th April 2004, 12:52 PM   #30
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Konnichiwa,

Quote:
Originally posted by fdegrove
So do I but that theory is still correct and is extremely logical in its approach.
Absolutely, but it has any relevance to sonics only if the lowest THD (meaning the lowest amount of 2nd harmonics for the SRPP) equates to the best sound, which it demonstrably does not.

Quote:
Originally posted by fdegrove
If you care to cross check, Jean Hiraga and our Japanese friends who original brought the circuit back to our attention showed exactly the same.
Actually, non of them insisted on a specifixed load and no other.

Quote:
Originally posted by fdegrove
Looking at Hiragas' SRPP phono stage you can't possibly miss the gigantic PS.
Looking at any other Hiraga Circuit you fnd the same extremely overbuild powersupplies, using unfortunatly very poor auality capacitors, hence the needs for such excess.

Quote:
Originally posted by fdegrove
Add to that the fact that almost all SRPP circuits ideally require separate envelopes for the triodes allowing each to have its heater biased up to cathode potential
As long as you keep the Supply voltage low(ish) you can actually use one envelope. It is only once you seriously turn up the HT (as found in many circuits inlcuding Hiraga) that you get the usual problems normally claimed to relate to the SRPP, but in reality relating to inappropriate use of the SRPP .

Quote:
Originally posted by fdegrove
and you'll see why I'm not all that convinced by this drop in a tube and forget about it thing.
Try it for a change, +B in the 200 region, heaters biased to 70V (as shown), pin 4 to positive heater voltage, pin 5 switchable +/- and pin 9 to negative Heater supply.

Quote:
Originally posted by fdegrove
Take it as you like but I've dabbled with SRPPs of all kinds over the passed twenty years and with all kinds of tubes and whatever the theory of operation, facts are still facts and SRPP circuits certainly are no exception to the rules.
Completely agreed. And the SRPP shown, when equipped with the Valves suggested and realised as suggested will work well within the rules, simply because it accounts for them sufficiently. Will it be the last word in performance - no. But for that you will need to carfully tune parts and circuit to specific DAC used, nothing "universal" will ever reach that.

Sayonara
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