I finally completed my second set of FE boards with all the suggested best parts including naked foil at R10. I got them tested and installed in their enclosures and am now listening to them. 9.2mV DC offset on one channel and 5.2 on the other, a little higher than my first build but still decent.
Wow what an amplifier! The difference is already quite easy to hear. Better defined string sounds, drum skin sounds are more realistic, bass is slightly warmer and a bit better defined in fact I'd say the whole range is a tad warmer which is nice. The sound stage seems a bit deeper too. The boutique components definitely improved this amp, it's just a shame they cost so much.
Huge thanks to Dario, Mauro, Bob & to everyone else involved, cheers folks!
Wow what an amplifier! The difference is already quite easy to hear. Better defined string sounds, drum skin sounds are more realistic, bass is slightly warmer and a bit better defined in fact I'd say the whole range is a tad warmer which is nice. The sound stage seems a bit deeper too. The boutique components definitely improved this amp, it's just a shame they cost so much.
Huge thanks to Dario, Mauro, Bob & to everyone else involved, cheers folks!
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For what it's worth I can only hear hum with my ear hard against the speaker drivers and that's with the PGND tab disconnected - the only ground connections are the 240V earth/ground to chassis and the transformer screen to chassis.
Oh and yeh I was a bit more generous with the heat sink paste than usual
Oh and yeh I was a bit more generous with the heat sink paste than usual
Very attractive and functional build. I especially like your layout, with the input leads being as short as possible and well away from line voltage.
Yes, those better parts cost a lot, but think of how long you'll enjoy listening to them. They are an investment, just like any tool.
Wow, that really is a lot of HS grease. You know a thin layer is actually more effective? Looks like most of it got squeezed out of the joint anyway.
Peace,
Tom E
Yes, those better parts cost a lot, but think of how long you'll enjoy listening to them. They are an investment, just like any tool.
Wow, that really is a lot of HS grease. You know a thin layer is actually more effective? Looks like most of it got squeezed out of the joint anyway.
Peace,
Tom E
Check that heatsinks are grounded too, that last bit of hum should disappear.
Hi Dario, heatsinks are grounded, the hum is VERY faint, there has to be silence in the house and my ear almost touching the drivers before I can hear it at all so I'm not concerned. Next time the lids are off I'll try disconnecting the transformer screen to chassis ground to see if that makes any difference.
Flux Clean-up
Since some of us have new boards from Group Buy Round 5 and are thinking about beginning our build, I thought I would share a short story about solder flux on boards.
A few years ago, I bought a well reviewed Chinese DAC that I enjoyed very much. About 6 months ago, I started to have intermittent drop out from my system and I eventually tracked it down to DC on the analog output of the DAC. I expected to find a burned or blown component in the power supply, but nothing look bad. Then I flipped the board over and found that they had never cleaned up the flux. After a few years, some of the flux had turned hard and white and definitely crossed tracks.
Naturally, I got out my old toothbrush and alcohol and got to scrubbing. After drying and reassembly, I checked the output voltage and found only millivolts DC. Everything plays beautifully and, so far, no drop outs.
So get out your rubbing alcohol and toothbrush or whatever flux cleaning tools you choose. It's always easier to clean up while the flux is still fresh and, yes, it is important.
Jac
PS: When I bought the DAC, there wasn't much improvement between the DAC in my Squeezebox Touch and the Yulong Chinese DAC. Since that time, I've built my FE's, got my pre-amp into the system, and upgraded components in my speaker crossover. Now the difference is clear and using the Yulong is very worthwhile. All these little projects do add up to better sound in the end.
Since some of us have new boards from Group Buy Round 5 and are thinking about beginning our build, I thought I would share a short story about solder flux on boards.
A few years ago, I bought a well reviewed Chinese DAC that I enjoyed very much. About 6 months ago, I started to have intermittent drop out from my system and I eventually tracked it down to DC on the analog output of the DAC. I expected to find a burned or blown component in the power supply, but nothing look bad. Then I flipped the board over and found that they had never cleaned up the flux. After a few years, some of the flux had turned hard and white and definitely crossed tracks.
Naturally, I got out my old toothbrush and alcohol and got to scrubbing. After drying and reassembly, I checked the output voltage and found only millivolts DC. Everything plays beautifully and, so far, no drop outs.
So get out your rubbing alcohol and toothbrush or whatever flux cleaning tools you choose. It's always easier to clean up while the flux is still fresh and, yes, it is important.
Jac
PS: When I bought the DAC, there wasn't much improvement between the DAC in my Squeezebox Touch and the Yulong Chinese DAC. Since that time, I've built my FE's, got my pre-amp into the system, and upgraded components in my speaker crossover. Now the difference is clear and using the Yulong is very worthwhile. All these little projects do add up to better sound in the end.
Hi everybody,
Have anyone tried these BOURNS resistors in place of the Caddock 903 recommended in the official BOM? At least on paper they seems to be better... and are cheaper, too.
http://it.farnell.com/resistori-foro-passante/gamma-prodotti/bourns-pwr4412-2s-series/pg/411770930
Have anyone tried these BOURNS resistors in place of the Caddock 903 recommended in the official BOM? At least on paper they seems to be better... and are cheaper, too.
http://it.farnell.com/resistori-foro-passante/gamma-prodotti/bourns-pwr4412-2s-series/pg/411770930
Hello everyone,
I just finished building the MyRef FE.
Besides a problem, now resolved, of cold welding that prevented the ignition of one of the modules,it played perfectly. I like it very much!
In testing I double checked the voltages and I noticed that on both modules instead of having -14V, I get -18V, the other voltages +14v are OK.
Visual analysis does not show anything wrong, the components are taken from Mouser (recommended BOM list ) with the only variant of ERO caps.
I'm not forcing them but they are playing since several days for hours. Temperatures are OK (about 30 °C).
Does anyone have any idea of the possible causes of such behavior? I suspect a anomaly in the BC640-16 I purchased.
I just followed the installation instructions provided by Dario!
Sergio
I just finished building the MyRef FE.
Besides a problem, now resolved, of cold welding that prevented the ignition of one of the modules,it played perfectly. I like it very much!
In testing I double checked the voltages and I noticed that on both modules instead of having -14V, I get -18V, the other voltages +14v are OK.
Visual analysis does not show anything wrong, the components are taken from Mouser (recommended BOM list ) with the only variant of ERO caps.
I'm not forcing them but they are playing since several days for hours. Temperatures are OK (about 30 °C).
Does anyone have any idea of the possible causes of such behavior? I suspect a anomaly in the BC640-16 I purchased.
I just followed the installation instructions provided by Dario!
Sergio
Sorry, cant see anything obvious so maybe an off spec component, maybe someone else can help identify which ones to test/replace??
Have you double checked for solder bridges, maybe between the AC in terminals and ground plane?
BTW I don't see a mains earth connection to chassis either!
Have you double checked for solder bridges, maybe between the AC in terminals and ground plane?
BTW I don't see a mains earth connection to chassis either!
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@scorda
I have seen about 16 V on one of my op amp power supply voltages. The regulated voltage power supply is for the LM318. It is OK up to +/- 20V, so I don't think you are causing any damage. I suspect that you are correct, that one of the components is off spec a bit and causing the different voltage.
Of course, Dario or others may be able to comment on the effect of the -18V, but I think you are OK. Just enjoy.
Jac
I have seen about 16 V on one of my op amp power supply voltages. The regulated voltage power supply is for the LM318. It is OK up to +/- 20V, so I don't think you are causing any damage. I suspect that you are correct, that one of the components is off spec a bit and causing the different voltage.
Of course, Dario or others may be able to comment on the effect of the -18V, but I think you are OK. Just enjoy.
Jac