Make sure the yellow output lead is connected to your RCA connector shield, and the orange lead is connected to the RCA connector center. From the sound if it, I wonder if it's possible that you haven't done that and what you're actually listening to is the capacitive leakage across the transformers. The loud hum is what makes me wonder if you've got the transformer mis-connected.
Jim
absolute phase
What difference does it make which leg of the tranformer output leads gets pulled to ground?
What difference does it make which leg of the tranformer output leads gets pulled to ground?
Hi,
accidently I have a gigawork dac on loan, and am mighty pleased by it, even with the stock configuration. It is a bit too tame then, but still good, regarding the electrolytics in the output...sacrilege...
Then of course the itch to fiddle or solder or both came up, and first I kicked out the Buffer opamp, sound opened up already. Then soldered 4 wires from the input of the 2,2 µF caps close to the dac-board (they are not in the path now) directly to the RCAs, and from there to the Pass DCB1 I am using.
I pulled out the other opamp, and left everything else as it is. Measured zero DC at the output, so I gave it a try and I am thrilled now. Very transparent and musical
But my question is: am I doing anything wrong? No transformer, and no cap in this case, but I am wondering where the 2,5 VDC went. They are still over those 2,2µ caps.
Is it possible that the B1 is doing what a transformer is doing?
Any comments?
Cheers,
Juergen
accidently I have a gigawork dac on loan, and am mighty pleased by it, even with the stock configuration. It is a bit too tame then, but still good, regarding the electrolytics in the output...sacrilege...
Then of course the itch to fiddle or solder or both came up, and first I kicked out the Buffer opamp, sound opened up already. Then soldered 4 wires from the input of the 2,2 µF caps close to the dac-board (they are not in the path now) directly to the RCAs, and from there to the Pass DCB1 I am using.
I pulled out the other opamp, and left everything else as it is. Measured zero DC at the output, so I gave it a try and I am thrilled now. Very transparent and musical
But my question is: am I doing anything wrong? No transformer, and no cap in this case, but I am wondering where the 2,5 VDC went. They are still over those 2,2µ caps.
Is it possible that the B1 is doing what a transformer is doing?
Any comments?
Cheers,
Juergen
Nothing, except for inverting the phase if you're inconsisent from primary to secondary.
Jim
Hi,
accidently I have a gigawork dac on loan, and am mighty pleased by it, even with the stock configuration. It is a bit too tame then, but still good, regarding the electrolytics in the output...sacrilege...
Then of course the itch to fiddle or solder or both came up, and first I kicked out the Buffer opamp, sound opened up already. Then soldered 4 wires from the input of the 2,2 µF caps close to the dac-board (they are not in the path now) directly to the RCAs, and from there to the Pass DCB1 I am using.
I pulled out the other opamp, and left everything else as it is. Measured zero DC at the output, so I gave it a try and I am thrilled now. Very transparent and musical
But my question is: am I doing anything wrong? No transformer, and no cap in this case, but I am wondering where the 2,5 VDC went. They are still over those 2,2µ caps.
Is it possible that the B1 is doing what a transformer is doing?
Any comments?
Cheers,
Juergen
you'll find the answer here...
http://www.diyaudio.com/forums/pass-labs/145201-building-symmetrical-psu-b1-buffer.html
Boky
Listening for the best attenuator load for direct out dacs
I listened to my AKM and CS direct out dacs to find the best load for a new stepped attenuator design. I like them into 15k the best. Read about it here.
.
http://www.diyaudio.com/forums/anal...enuator-load-direct-out-akm-cs-dac-chips.html
.
I listened to my AKM and CS direct out dacs to find the best load for a new stepped attenuator design. I like them into 15k the best. Read about it here.
.
http://www.diyaudio.com/forums/anal...enuator-load-direct-out-akm-cs-dac-chips.html
.
Pardon me if this has already come up... but has the price jumped on the gigawork dac?
I had been saving my pennies for the dac, I think it was $90 or so, without the transformer. Now all I see in the ebay store is $120 (+ extra $10 for shipping).
Is this just a momentary quirk of the Gigawork store, or is that the way it is now? Is the transformer in the kit worth the extra price? It was mmm.... Jan 20 or so I last saw it w/o the trafo.
I had been saving my pennies for the dac, I think it was $90 or so, without the transformer. Now all I see in the ebay store is $120 (+ extra $10 for shipping).
Is this just a momentary quirk of the Gigawork store, or is that the way it is now? Is the transformer in the kit worth the extra price? It was mmm.... Jan 20 or so I last saw it w/o the trafo.
An r-2r/shunt stepped atenuator project is also presented here http://www.diyaudio.com/forums/anal...ther-volume-controlers-source-selections.html
Regards,
Tibi
I paid $90 + $20 shipping (without transformer) a few months ago. Now it looks as if Gigawork is only selling them with transfomers. Maybe he just hasn't relisted any of the non-transformers kits yet.
You can also get the same board without transformer for $95 with free shipping from here 2010 UP-SAMPLING 24bit/192Hz DAC DA CONVERTER W/USB KIT 24bit/192Hz DAC DA CONVERTER @ USB Kit [217] - US$95.00 : Hifi Diy--Amplifier,dac kits,hifi audio products and parts online shop, shipping to worldwide
Transformers and modules for sale
http://www.diyaudio.com/forums/swap...rd-transformers-pcm1798-sale.html#post2458746
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For sale shipping included to US addresses:
1 pair Jensen JT-11-YMPC. $50
.
http://www.jensen-transformers.com/datashts/11ympc.pdf
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1 pair Edcor XSM 600/10k. $25
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EDCOR Electronics Corporation. XSM600/10K
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1 Pair Edcor MXL8CS wired to PCM1798 module for trans I/V out with RCA output connectors and ready to plug in to Gigaworks Big Dac Board. $100
.
EDCOR Electronics Corporation. MXL8cs
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Spare PCM1798 module. $30.
http://www.diyaudio.com/forums/swap...rd-transformers-pcm1798-sale.html#post2458746
.
For sale shipping included to US addresses:
1 pair Jensen JT-11-YMPC. $50
.
http://www.jensen-transformers.com/datashts/11ympc.pdf
.
1 pair Edcor XSM 600/10k. $25
.
EDCOR Electronics Corporation. XSM600/10K
.
1 Pair Edcor MXL8CS wired to PCM1798 module for trans I/V out with RCA output connectors and ready to plug in to Gigaworks Big Dac Board. $100
.
EDCOR Electronics Corporation. MXL8cs
.
Spare PCM1798 module. $30.
Jensen
I like the Vout dacs better. I never did buy any of the Edcors at 1:1 so I don't know what the XSM would sound like but they are very cheap. The Jensen JT-11-EMCF is probably a little better than the FMCF but they are very close. With the perfect load of my test attenuators, the Dayton foil caps still sound a little better but the transformers sound great into everything. Surprisingly, revisiting the AK4395 vs CS43122 through the new attenuators, I would put them back on par. Different but one not better than the other. The 4395 is better than the 4396.
Sendler,
What was your final decision on the trannies? I assume your done?
I like the Vout dacs better. I never did buy any of the Edcors at 1:1 so I don't know what the XSM would sound like but they are very cheap. The Jensen JT-11-EMCF is probably a little better than the FMCF but they are very close. With the perfect load of my test attenuators, the Dayton foil caps still sound a little better but the transformers sound great into everything. Surprisingly, revisiting the AK4395 vs CS43122 through the new attenuators, I would put them back on par. Different but one not better than the other. The 4395 is better than the 4396.
