The advantage of dual mono configuration has been explained here: http://www.diyaudio.com/forums/audi...-kit-building-instructions-4.html#post1517735
How much difference it actually makes will depend on build quality, parts chosen and your complete setup.
You would only need a second transformer for dual mono configuration.
How much difference it actually makes will depend on build quality, parts chosen and your complete setup.
You would only need a second transformer for dual mono configuration.
DAC worked. Again, the system makes me hi-fi feelings
Peter,
I just powered SPDIF DAC about an hour ago.
Source is a Phillips DVD729K, using its digital coaxial (RCA) out.
Coaxial cable is Eurotronic RG 59B/U with unknown brand BNC connectors. The cable is used item and I bought it from a Asset & Recovery shop. As I don't have BNC-male RCA adapter, I used two wires directly conntected from one BNC connector to Phillips digital RCA out.
After double checking the board, setting up connections, plugging interconnect cable from DAC to ready-on amp, I switched power on. A "uhkk" sound from speaker announced me that the DAC got powered.
Pressed Play on the Phillips. Voila, sounds, music, .... and happy. It worked.
Cannot say anything about its performance as this is also the first time I listen music from this Phillips. I just borrowed it from my landlord to test the DAC.
But it worked. And I will need time to setle down my listening while the DAC is burned-in.
Thanks a lot, Peter, for great design kit and helps.
HT
Peter,
I just powered SPDIF DAC about an hour ago.
Source is a Phillips DVD729K, using its digital coaxial (RCA) out.
Coaxial cable is Eurotronic RG 59B/U with unknown brand BNC connectors. The cable is used item and I bought it from a Asset & Recovery shop. As I don't have BNC-male RCA adapter, I used two wires directly conntected from one BNC connector to Phillips digital RCA out.
After double checking the board, setting up connections, plugging interconnect cable from DAC to ready-on amp, I switched power on. A "uhkk" sound from speaker announced me that the DAC got powered.
Pressed Play on the Phillips. Voila, sounds, music, .... and happy. It worked.
Cannot say anything about its performance as this is also the first time I listen music from this Phillips. I just borrowed it from my landlord to test the DAC.
But it worked. And I will need time to setle down my listening while the DAC is burned-in.
Thanks a lot, Peter, for great design kit and helps.
HT
Quick sanity check before installing r-cores in GCs (electrostatic screen connection)
Hi all,
I've received 2x 2x24V 300VA r-cores from Selectronic, to replace my buzzing Sedlbauers (http://www.diyaudio.com/forums/audi...ip-amp-kits-dacs-chassis-279.html#post2557178)
The Sedlbauers have two input leads, and four out, whereas the r-cores have an additional 'electrostatic screen' (physically on the same side as the mains in), marked 'Ecran' here: http://www.selectronic.fr/upload/produit/pagecatalogue/9-05.pdf
There's no guidance in the doc about the screen connection, so I presume it gets connected to input earth/chassis ground.
I have a single (star) ground point on the chassis - should I connect there, or at the mains inlet, from which I would also keep the existing ground?
Any guidance appreciated,
Steve
Hi all,
I've received 2x 2x24V 300VA r-cores from Selectronic, to replace my buzzing Sedlbauers (http://www.diyaudio.com/forums/audi...ip-amp-kits-dacs-chassis-279.html#post2557178)
The Sedlbauers have two input leads, and four out, whereas the r-cores have an additional 'electrostatic screen' (physically on the same side as the mains in), marked 'Ecran' here: http://www.selectronic.fr/upload/produit/pagecatalogue/9-05.pdf
There's no guidance in the doc about the screen connection, so I presume it gets connected to input earth/chassis ground.
I have a single (star) ground point on the chassis - should I connect there, or at the mains inlet, from which I would also keep the existing ground?
Any guidance appreciated,
Steve
My 3875 premium kit sounds great, but I had a weird problem
I finally finished assembly of the kit in my box. I will not try Stainless Steel 304 again. It's too hard to cut.
Definitely a very nice sounding amp.
Less than 50 mV DC in the output channels with "open" inputs and volume at full.
It powers my speakers, and alternatively my Stax electrostatic headphones nicely. The sound is very clear, and my 15 yr old son thinks it's a lot better than our other stuff in the house. (his ears are better than mine)
When I was assembling it, I ran into a problem blowing fuses. I mounted the power supply board to an Aluminum angle, with screws running through the diode metal tab holes. Are those metal tabs NOT okay to be grounded? All I can tell is that it seems like that was the cause of blowing fuses. I went up to 6.3Amp slow blow fuses in my power input module.
2nd question: it is possible to increase the gain a little? I'm using a 20K log taper stereo pot for the input, and the R1, R2, etc. resistors as supplied in the kit.
Thanks for a fun experience.
I finally finished assembly of the kit in my box. I will not try Stainless Steel 304 again. It's too hard to cut.
Definitely a very nice sounding amp.
Less than 50 mV DC in the output channels with "open" inputs and volume at full.
It powers my speakers, and alternatively my Stax electrostatic headphones nicely. The sound is very clear, and my 15 yr old son thinks it's a lot better than our other stuff in the house. (his ears are better than mine)
When I was assembling it, I ran into a problem blowing fuses. I mounted the power supply board to an Aluminum angle, with screws running through the diode metal tab holes. Are those metal tabs NOT okay to be grounded? All I can tell is that it seems like that was the cause of blowing fuses. I went up to 6.3Amp slow blow fuses in my power input module.
2nd question: it is possible to increase the gain a little? I'm using a 20K log taper stereo pot for the input, and the R1, R2, etc. resistors as supplied in the kit.
Thanks for a fun experience.
PROBLEM: DAC is suddenly silent! Please help
Peter,
I've got problem with the DAC. It happened on last weekend when I moved my system from my room to the living room. After setting up everything for so called media center (DVD player, TV, TV Receiver, GC Amp, DAC, PSP, and pair of JBL 2080 and all proper connections), I tested and all worked fine.
Just yesterday evening, I bought a RCA-BNC adapter for DVD player coaxial digital out and used it for the BNC-BNC 75ohm coaxial cable to the DAC (before that, I used a direct wires connected from coaxial RCA output to the cable). After checking everything, I turned the DAC, then the Amp and tried to play a CD. But no sound came out.
Thought it might be amp problem, I tried direct link from DVDplayer's audio out. Sound is OK. But whenever I tried with DAC on, I got nothing.
I separated the DAC and measured voltage as suggested from your instruction diagram, I've got :
- 5.074V, 5.095V and 5.051V out at 3 AN8005s.
- 7.95V out at AN8008
- at TDA1543: 4.092V at 6, 2.101V at 7 and 4.11V at 8.
I thought that all outputs were fine comparing to the values on the diagram, then I connected the DAC back to my testing system: the PC's CDROM with digital out, GC and one speaker and they are separated from everything else (no TV, no computer, no PSP, no TV receiver). At first, it was not working - no sounds out from the speaker although I could listen to the music via my headphone plugged onto the CDROM. My brother found that the input on coaxial cable from CDROM end was shorted (it's very easily to occur like this as I used direct wires connecting from CDROM to coaxial cable on that end). Double checked and turned all on. Sound was back.
Then I attached DAC and Amp back to the media center. Turned all on. No sounds!!!!!
Doubted I'd made something wrong, I double checked again with everything, even with DAC's output voltages. All connections are OK and voltage values are exactly the same as above. But I cannot have the sound if DAC is attached. (Again, sound is OK with direct connect from source's audio out)
What is really happening? Did I accidently kill some components on the DAC's board? How do I fix this?
Many thanks,
HT
Peter,
I've got problem with the DAC. It happened on last weekend when I moved my system from my room to the living room. After setting up everything for so called media center (DVD player, TV, TV Receiver, GC Amp, DAC, PSP, and pair of JBL 2080 and all proper connections), I tested and all worked fine.
Just yesterday evening, I bought a RCA-BNC adapter for DVD player coaxial digital out and used it for the BNC-BNC 75ohm coaxial cable to the DAC (before that, I used a direct wires connected from coaxial RCA output to the cable). After checking everything, I turned the DAC, then the Amp and tried to play a CD. But no sound came out.
Thought it might be amp problem, I tried direct link from DVDplayer's audio out. Sound is OK. But whenever I tried with DAC on, I got nothing.
I separated the DAC and measured voltage as suggested from your instruction diagram, I've got :
- 5.074V, 5.095V and 5.051V out at 3 AN8005s.
- 7.95V out at AN8008
- at TDA1543: 4.092V at 6, 2.101V at 7 and 4.11V at 8.
I thought that all outputs were fine comparing to the values on the diagram, then I connected the DAC back to my testing system: the PC's CDROM with digital out, GC and one speaker and they are separated from everything else (no TV, no computer, no PSP, no TV receiver). At first, it was not working - no sounds out from the speaker although I could listen to the music via my headphone plugged onto the CDROM. My brother found that the input on coaxial cable from CDROM end was shorted (it's very easily to occur like this as I used direct wires connecting from CDROM to coaxial cable on that end). Double checked and turned all on. Sound was back.
Then I attached DAC and Amp back to the media center. Turned all on. No sounds!!!!!
Doubted I'd made something wrong, I double checked again with everything, even with DAC's output voltages. All connections are OK and voltage values are exactly the same as above. But I cannot have the sound if DAC is attached. (Again, sound is OK with direct connect from source's audio out)
What is really happening? Did I accidently kill some components on the DAC's board? How do I fix this?
Many thanks,
HT
DAC with Toslink
Peter,
*
One more question.
I want to include Toslink to the DAC. Can you provide the part number (e.g. Digikey or Farnell) of the additional components for Toslink module to the DAC?
The problem is that I cannot select the right part for optical receiver. Different values in nm confuse me.
*
Thank you very much.
HT
Peter,
*
One more question.
I want to include Toslink to the DAC. Can you provide the part number (e.g. Digikey or Farnell) of the additional components for Toslink module to the DAC?
The problem is that I cannot select the right part for optical receiver. Different values in nm confuse me.
*
Thank you very much.
HT
Attachments
I don't think you can damage the DAC with a faulty cable as there are blocking caps at the input, maybe try a DAC with a different cable or different source.
For Toslink, you can use TORX177 or similar: Digi-Key - TORX177FT-ND (Manufacturer - TORX177(F,T))
For Toslink, you can use TORX177 or similar: Digi-Key - TORX177FT-ND (Manufacturer - TORX177(F,T))
Many thanks for quick reply.
I have tried the DAC with two sources: DVD player and CDROM with Digital out. First, I checked that they both work fine with their analog audio output connected to the Amp. Then I connected to their digital out to the DAC. No sound.
The interconnect cable from DAC to Amp works as I also use it for connecting from source's analog output to Amp.
I checked the coaxial cable. It is OK: no shortcut.
I wonder if any chance:
- the digital out from both sources had been damaged (!). I will borrow another DVD player for testing.
- any chip or cap on the DAC had been damaged. How can I measure and check if the onboard caps and chips are OK?
As I can detect a little electric shock when touching to the TV metal cover, I am wondering if any kind of such shock would kill a chip or a cap on the DAC. But I can still measure the right voltage values at the points you indicated on DAC's diagram.
Do I need an oscilloscope?
Thanks,
HT
I have tried the DAC with two sources: DVD player and CDROM with Digital out. First, I checked that they both work fine with their analog audio output connected to the Amp. Then I connected to their digital out to the DAC. No sound.
The interconnect cable from DAC to Amp works as I also use it for connecting from source's analog output to Amp.
I checked the coaxial cable. It is OK: no shortcut.
I wonder if any chance:
- the digital out from both sources had been damaged (!). I will borrow another DVD player for testing.
- any chip or cap on the DAC had been damaged. How can I measure and check if the onboard caps and chips are OK?
As I can detect a little electric shock when touching to the TV metal cover, I am wondering if any kind of such shock would kill a chip or a cap on the DAC. But I can still measure the right voltage values at the points you indicated on DAC's diagram.
Do I need an oscilloscope?
Thanks,
HT
Finished LM3875 kit
Well recently finished Peter's LM3875 kit, burnt it in for quite a few hours and been seriously listening to it for the last few days - must say I am seriously impressed. I have never been an out and out hifi fanatic and never owned any really high end stuff but this little amp is giving me such listening pleasure. Its so silent, not a trace of hiss or hum, and there is so much new subtle detail and effortless performance being extracted from my fairly humble source (small NAD AV receiver system via), and it runs beautifully cool. Speakers are the tiny PMC DB1+S transmission line monitors. The PS uses Airlink 2x22v transformer (easily available here in UK) and is remote from amp. Using stock 1500uf on amp board, and 470uf Panas on rectifier board - no snubbers or zobells. Here are a few pictures of finished article.
Interior shot
Exterior
Exterior with CD for size reference
Had a session at my son's place last night and using his Cambridge Audio CD player and Beresford DAC brought even more out. So the source is my weak link not the little amp. I wonder what this amp sounds like with really high end source, speakers and interconnects. Damn, got me thinking now! Also did a comparison with his monstrous XTZ Class AP-100 class A Power Amplifier and I felt the LM3875 amp was not shamed in any way.
So a big thank you to Peter for making this stuff available to us and for his inspiration and excellent support here. It's been an eye opener and I have a feeling I am now on the slippery slope to poverty.
Well recently finished Peter's LM3875 kit, burnt it in for quite a few hours and been seriously listening to it for the last few days - must say I am seriously impressed. I have never been an out and out hifi fanatic and never owned any really high end stuff but this little amp is giving me such listening pleasure. Its so silent, not a trace of hiss or hum, and there is so much new subtle detail and effortless performance being extracted from my fairly humble source (small NAD AV receiver system via), and it runs beautifully cool. Speakers are the tiny PMC DB1+S transmission line monitors. The PS uses Airlink 2x22v transformer (easily available here in UK) and is remote from amp. Using stock 1500uf on amp board, and 470uf Panas on rectifier board - no snubbers or zobells. Here are a few pictures of finished article.
Interior shot
Exterior
Exterior with CD for size reference
Had a session at my son's place last night and using his Cambridge Audio CD player and Beresford DAC brought even more out. So the source is my weak link not the little amp. I wonder what this amp sounds like with really high end source, speakers and interconnects. Damn, got me thinking now! Also did a comparison with his monstrous XTZ Class AP-100 class A Power Amplifier and I felt the LM3875 amp was not shamed in any way.
So a big thank you to Peter for making this stuff available to us and for his inspiration and excellent support here. It's been an eye opener and I have a feeling I am now on the slippery slope to poverty.
Bent Audio Transformers
Hi Peter Thank you for shipping the 3875 amp kit.
I plan on building a dual mono version.
I have a spare Bent Audio / Slagel audio transformer that is simply collecting dust.
I would like to use it in the build out as my vol. control.
It has the remote and LED display.
The question is...
What do I need to do to be able to use it?
I currently use a couple of them with my 45 amps and Pass Lab amps... WONDERFUL
Thank you for building the kit etc.
Phil and Christine
Santa Fe, NM
Hi Peter Thank you for shipping the 3875 amp kit.
I plan on building a dual mono version.
I have a spare Bent Audio / Slagel audio transformer that is simply collecting dust.
I would like to use it in the build out as my vol. control.
It has the remote and LED display.
The question is...
What do I need to do to be able to use it?
I currently use a couple of them with my 45 amps and Pass Lab amps... WONDERFUL
Thank you for building the kit etc.
Phil and Christine
Santa Fe, NM
You can use it exactly the same way as with other amps. Here how I use TVC in one of my amps: http://www.diyaudio.com/forums/audio-sector/76609-most-advanced-gainclone-amp-yet.html
Thank You for fast reply. !!!
I shall use John and Daves Transformer Vol control... Very happy... I think Dave would **** if he knew.
One more mind numbing question...
The Bybee guy makes a power supply filter? or some wild *** thing...
He says it will lower PS floor noise... Life without hash? Gee that sorta came out kinda wrong. Life with out AC crude. Crude not crud. Crude crud. Back to hash...
Looks like you put one on each rail.
They come in two flavors... 2 Amps and 15 amps...
I have NEVER used Any of his stuff BUT... maybe a chip amp could, just maybe benefit from such voodoo... Its like they both kind of look the same too. The Chip amp and the ByBee thingy.
Has anyone one ventured into that "can-o-worms"?
Phil Townsend
East of the Rio Grande
West of the Pecos
Santa Fe, NM
And will the all new Mark Audio AlPair 7
replace My Feastrex????
We shall see... we shall see.
I shall use John and Daves Transformer Vol control... Very happy... I think Dave would **** if he knew.
One more mind numbing question...
The Bybee guy makes a power supply filter? or some wild *** thing...
He says it will lower PS floor noise... Life without hash? Gee that sorta came out kinda wrong. Life with out AC crude. Crude not crud. Crude crud. Back to hash...
Looks like you put one on each rail.
They come in two flavors... 2 Amps and 15 amps...
I have NEVER used Any of his stuff BUT... maybe a chip amp could, just maybe benefit from such voodoo... Its like they both kind of look the same too. The Chip amp and the ByBee thingy.
Has anyone one ventured into that "can-o-worms"?
Phil Townsend
East of the Rio Grande
West of the Pecos
Santa Fe, NM
And will the all new Mark Audio AlPair 7
replace My Feastrex????
We shall see... we shall see.
Bybee Music Rails have been discussed here: http://www.diyaudio.com/forums/everything-else/182070-bybee-music-rails.html
I don't see a reason not to try them (although I didn't yet)
I don't see a reason not to try them (although I didn't yet)
Caps
Black Gates are no longer made and basically unobtainium.
Has anyone used the Nichicon Muse Premium and the Nichicon ES Bi-Polar?
Parts Connextion says they got the ES Bi_Polars to replace the BG N's.... But this , to me, seems a stretch. Those little Red 1000 mike guys were the best of the best.
I have used the Panasonics etc but have never found a great replacement for the BG REDS.
Any Help???
Black Gates are no longer made and basically unobtainium.
Has anyone used the Nichicon Muse Premium and the Nichicon ES Bi-Polar?
Parts Connextion says they got the ES Bi_Polars to replace the BG N's.... But this , to me, seems a stretch. Those little Red 1000 mike guys were the best of the best.
I have used the Panasonics etc but have never found a great replacement for the BG REDS.
Any Help???
Check I2S lines with scope.
Hi Peter,
I've checked as you said. Got sin waves at gates 1,2, and 3 of TDA1543 when DAC is on and no digital in. But when digital was connected, I got flat signal.
I again checked output voltages at indicated positions. All values are very close to the values you have suggested in the DAC's diagram.
That is not normal, right?
What would be happening in the DAC?
Thanks,
HT
Hi Peter,
I've checked as you said. Got sin waves at gates 1,2, and 3 of TDA1543 when DAC is on and no digital in. But when digital was connected, I got flat signal.
I again checked output voltages at indicated positions. All values are very close to the values you have suggested in the DAC's diagram.
That is not normal, right?
What would be happening in the DAC?
Thanks,
HT
Last edited:
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