My new tube DAC output

Algar_emi · 17th April 2003, 01:28 AM

Here my new tube voltage gain stage for my new DIY DAC. It is using a HV 6X4 Tube rectifier and a double triode Svotek 6922. The 6922 is using DC filement voltage using schottky rectifer and LM317T regulator. The HV is filtered using a CLC filter with two 47uF cap. an a Hammond 9H, 40ma choke.

Algar_emi · 17th April 2003, 01:31 AM

And I just forgot. I'm also using in the signal path all copper Riken resistors and the very good Jensen copper foil and silver lead.

I will listen to this beauty soon...

Comments are welcome. Any suggestion on my tube choice will also be appreciated.

Don't be too hard on me, it is my first tube circuit. Better late than never.

Bye...

Algar_emi · 17th April 2003, 01:42 AM

Since the DAC is not completed, here a few measurements to test everything:

Bandwidth (0.767V, 1Khz reference): 20Hz-300Khz in 50 Kohms

Voltage Gain (in 50Kohms)
0.5Vin = 22.5
31.6mVin (Vout=0dB) = 24.2

Distorsion (in 50Kohms, Vout 0.767V)
100Hz: 0.5%
1Khz: 1.2%
10Khz: 1.4%
20Khz: 1.5%

Are these values of distorsion typical or an other tube brand can give me better values?

Peter Daniel · 17th April 2003, 02:45 AM

Quote:

Originally posted by Algar_emi
And I just forgot. I'm also using in the signal path all copper Riken resistors and the very good Jensen copper foil and silver lead.

You know that those caps have outer foil marked and I found that when outer foil is directed towards the load, it sounds better.

Algar_emi · 17th April 2003, 12:19 PM

I was wondering I to connect them. Thanks Peter for the tip...

SB

Peter Daniel · 17th April 2003, 12:25 PM

The outer foil is marked with a line.

mig-ru · 17th April 2003, 12:41 PM

Algar_emi,

That looks awesome! I think I might just try tackling a DIY tube DAC. Where did you get the schematic for it, would be interesting to look at.

JOE DIRT® · 17th April 2003, 01:01 PM

I dont know the exact Engineering on those caps but its almost like they are polarised like an electrolytic cap and what peter has said seems to be true....and to comment on your distortion levels....isnt that what your looking for in a tube design?????....that does make the nuiance warm and proprietary with a tube design.....Live music is never perfect and audiofiles are ultimatley trying to re create a live performance not a mixed studio version

Cheers!!The DIRT®

colwaiting · 17th April 2003, 01:34 PM

Excellent. All done on a R.S. project board!
I' d like to know about that ceramic 6dj8 tube socket.
Also evrything you know about the 1/v conversion at the output of the dac. (impedances, levels) this area still confuses me a bit.>>Doug

Algar_emi · 17th April 2003, 08:09 PM

I got them from www.partsconnexion.com in Canada. They have gold plated pins also.

17th April 2003, 01:31 AM	#2
Algar_emi diyAudio Member Join Date: Oct 2002 Location: Canada, Qc	Coupling caps And I just forgot. I'm also using in the signal path all copper Riken resistors and the very good Jensen copper foil and silver lead. I will listen to this beauty soon... Comments are welcome. Any suggestion on my tube choice will also be appreciated. Don't be too hard on me, it is my first tube circuit. Better late than never. Bye...

17th April 2003, 01:42 AM	#3
Algar_emi diyAudio Member Join Date: Oct 2002 Location: Canada, Qc	And a few measurements Since the DAC is not completed, here a few measurements to test everything: Bandwidth (0.767V, 1Khz reference): 20Hz-300Khz in 50 Kohms Voltage Gain (in 50Kohms) 0.5Vin = 22.5 31.6mVin (Vout=0dB) = 24.2 Distorsion (in 50Kohms, Vout 0.767V) 100Hz: 0.5% 1Khz: 1.2% 10Khz: 1.4% 20Khz: 1.5% Are these values of distorsion typical or an other tube brand can give me better values?

17th April 2003, 12:19 PM	#5
Algar_emi diyAudio Member Join Date: Oct 2002 Location: Canada, Qc	Cap direction I was wondering I to connect them. Thanks Peter for the tip... SB

17th April 2003, 12:25 PM	#6
Peter Daniel diyAudio Member Join Date: Jul 2002 Location: Toronto, Canada	The outer foil is marked with a line. __________________ www.audiosector.com “Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC

17th April 2003, 01:34 PM	#9
colwaiting diyAudio Member Join Date: Dec 2002 Location: boston Ma.	tube dac Excellent. All done on a R.S. project board! I' d like to know about that ceramic 6dj8 tube socket. Also evrything you know about the 1/v conversion at the output of the dac. (impedances, levels) this area still confuses me a bit.>>Doug

17th April 2003, 12:41 PM	#7
mig-ru diyAudio Member Join Date: Jul 2002 Location: Boulder, CO	Algar_emi, That looks awesome! I think I might just try tackling a DIY tube DAC. Where did you get the schematic for it, would be interesting to look at.

17th April 2003, 01:01 PM	#8
JOE DIRT® diyAudio Member Join Date: Apr 2003 Location: Brantford, ON	I dont know the exact Engineering on those caps but its almost like they are polarised like an electrolytic cap and what peter has said seems to be true....and to comment on your distortion levels....isnt that what your looking for in a tube design?????....that does make the nuiance warm and proprietary with a tube design.....Live music is never perfect and audiofiles are ultimatley trying to re create a live performance not a mixed studio version Cheers!!The DIRT®

17th April 2003, 08:09 PM	#10
Algar_emi diyAudio Member Join Date: Oct 2002 Location: Canada, Qc	Tube socket I got them from www.partsconnexion.com in Canada. They have gold plated pins also.

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