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Old 4th July 2011, 05:44 PM   #51
Ryssen is offline Ryssen  Sweden
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I understand many of you use Caddok resitor as I/V stage.But there are many variants of the caddok resistors.
Exact vad resistor did you use?
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Old 5th July 2011, 12:07 AM   #52
Jogi is offline Jogi  Germany
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The Texas TX2575 resistors seem to be even better than the Caddock MK-132, they are available at partsconnexion.
BTW the most important thing with this dac is the output stage. Everything else is more or less cosmetics...I ended up with a C3g (fantastic tubes) in triode mode and a Lundahl LL1660 as output transformer. Wonderful sound, and much much much better than the former E182cc with capacitor output. Last step would be a Sowter I/V transformer, but they are not cheap.
And I much prefer a choke in the HV-powersupply instead the 470R resistor. I liked it so much, I even put 2 chokes in...and a decent 100f film cap as last PS cap.

have fun,

Juergen
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Old 5th July 2011, 01:12 AM   #53
Ryssen is offline Ryssen  Sweden
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So has anyone really heard difference with the Caddok or the Texan resisotors
is it worth uppgrading?

I do now use Lundahls trafo at the output but dont like the sound thats why I am building the tubestage.Will use the 6H30.
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Old 5th July 2011, 01:46 AM   #54
Ryssen is offline Ryssen  Sweden
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Quote:
And I much prefer a choke in the HV-powersupply instead the 470R resistor.
What value on the choke did you use?
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Old 5th July 2011, 02:27 PM   #55
Jogi is offline Jogi  Germany
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I don't know. These are from an old tube radio, and have a resistance of about 300ohms. I guess around 15hy, 10 would be also fine. Each has a voltage drop of about 20V, and I also use a 6X4 tube rectifier, so another 20V drop. Transformer is 250-0-250, but at the last PS-cap there is only 200V DC left, which is perfectly fine for the C3g ande shunt running with 70mA.
For trying out a choke I would take just what you have in the box, or get some old radio stuff, its good quality from the 50ies...
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Old 6th July 2011, 05:56 AM   #56
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Quote:
Originally Posted by Ryssen View Post
I understand many of you use Caddok resitor as I/V stage.But there are many variants of the caddok resistors.
Exact vad resistor did you use?
200R!
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Old 12th July 2011, 08:40 AM   #57
tyo94 is offline tyo94  Indonesia
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Quote:
Originally Posted by Jogi View Post
The Texas TX2575 resistors seem to be even better than the Caddock MK-132, they are available at partsconnexion.
BTW the most important thing with this dac is the output stage. Everything else is more or less cosmetics...I ended up with a C3g (fantastic tubes) in triode mode and a Lundahl LL1660 as output transformer. Wonderful sound, and much much much better than the former E182cc with capacitor output. Last step would be a Sowter I/V transformer, but they are not cheap.
And I much prefer a choke in the HV-powersupply instead the 470R resistor. I liked it so much, I even put 2 chokes in...and a decent 100f film cap as last PS cap.

have fun,

Juergen
Isn't C3G a high gain tube (even used as triode strapped)? What value of Rk and Ra which you use to reduce the gain?

Tyo
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Old 12th July 2011, 09:27 AM   #58
Jogi is offline Jogi  Germany
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Yes, it is high gain, but the Lundahl is connected 4,5:1 as stepdown to lower the output impedance. So there is no Ra, Rk I took 150 Ohm to get about 14-15 mA. More could be better, but the Lundahl is normally only up to 10mA. Voltage at the anode is 160 Volt.
And preamp is DCB1, so no gain in the there...So there is even not enough gain, I am really thinking about Sowter I/V transformers, as these have some step up.

cheers,

Juergen
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Old 12th July 2011, 06:38 PM   #59
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... C3g in triode mode and a Lundahl LL1660 as output transformer ?

It is possible see my Phono End
Hi-end phono preamplifier
a single C3g per channel with LL1660/10mA 4.5:4 or 4,5:2 will be ok but much more expensive
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Old 14th July 2011, 01:51 AM   #60
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Default The bom of DAC-end update 2011, Best layout, best sound

Best layout, best sound
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File Type: zip Bom DAC-END 2011.zip (18.0 KB, 405 views)
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