I finally finished putting my FSP build with pcbs from the Group Buy into an enclosure (two actually), only took about ten times as long as putting together the circuit itself 
The build turned out quite alright, no noise, no hum, couldn't be happier.
I've used Vishay Dale RN and PRP resistors, Panasonic FM and Nichicon Muse electrolytic caps, Mundorf MCap EVO (output) and Russian FT-3 (interstage) coupling caps in the circuit, and Nichicon KG Super Through caps in the PSU. Per channel, the power supply has 4700uF in the PSU enclosure and 4700uF in the amplifier enclosure, for a total of about 10000uF per channel.
When I last measured, the supply voltage of the raw supply was 48.00V/48.00V L/R (with ripple voltage in the 20mV region, checked with a scope), the rail voltage settled at 32.55V/32.57V and the TP2-voltage was at 3.601V/3.597V. I set the voltages with VR2x alone, while VR1 remained in the middle position. Looks alright, I think.
As many before me have already said, this preamp sounds wonderful! Thank you Salas for sharing and evolving the circuit and thank you Tea-Bag for organizing all those group buys!
The build turned out quite alright, no noise, no hum, couldn't be happier.I've used Vishay Dale RN and PRP resistors, Panasonic FM and Nichicon Muse electrolytic caps, Mundorf MCap EVO (output) and Russian FT-3 (interstage) coupling caps in the circuit, and Nichicon KG Super Through caps in the PSU. Per channel, the power supply has 4700uF in the PSU enclosure and 4700uF in the amplifier enclosure, for a total of about 10000uF per channel.
When I last measured, the supply voltage of the raw supply was 48.00V/48.00V L/R (with ripple voltage in the 20mV region, checked with a scope), the rail voltage settled at 32.55V/32.57V and the TP2-voltage was at 3.601V/3.597V. I set the voltages with VR2x alone, while VR1 remained in the middle position. Looks alright, I think.
As many before me have already said, this preamp sounds wonderful! Thank you Salas for sharing and evolving the circuit and thank you Tea-Bag for organizing all those group buys!
Attachments
Your question brings this post to mind: http://www.diyaudio.com/forums/parts/35821-some-noise-measurements-leds-zener-diodes.html
Nice use of the dual ground lug input sockets. Anti-phase loops for interference cancellation.
Lot's of twisted pairs for low interference.
Use of small loop areas.
Very well done.
Only one adverse comment:
The very long screen connection must have a high inductance. That inductance defeats the RF screening ability of the screen.
In my non expert view that screen connection must be VERY SHORT and bolted to the chassis right next to where the lead comes out through the transformer insulation.
Turn the transformer upside down to make that connection even shorter.
Lot's of twisted pairs for low interference.
Use of small loop areas.
Very well done.
Only one adverse comment:
The very long screen connection must have a high inductance. That inductance defeats the RF screening ability of the screen.
In my non expert view that screen connection must be VERY SHORT and bolted to the chassis right next to where the lead comes out through the transformer insulation.
Turn the transformer upside down to make that connection even shorter.
I finally finished putting my FSP build with pcbs from the Group Buy into an enclosure (two actually), only took about ten times as long as putting together the circuit itself
I've used Vishay Dale RN and PRP resistors, Panasonic FM and Nichicon Muse electrolytic caps, Mundorf MCap EVO (output) and Russian FT-3 (interstage) coupling caps in the circuit, and Nichicon KG Super Through caps in the PSU. Per channel, the power supply has 4700uF in the PSU enclosure and 4700uF in the amplifier enclosure, for a total of about 10000uF per channel.
When I last measured, the supply voltage of the raw supply was 48.00V/48.00V L/R (with ripple voltage in the 20mV region, checked with a scope), the rail voltage settled at 32.55V/32.57V and the TP2-voltage was at 3.601V/3.597V. I set the voltages with VR2x alone, while VR1 remained in the middle position. Looks alright, I think.
As many before me have already said, this preamp sounds wonderful! Thank you Salas for sharing and evolving the circuit and thank you Tea-Bag for organizing all those group buys!
Excellent build details. Congratulations & enjoy. Is that a vintage Dual TT you got there?
Well, that confirms my doubts. I was actually thinking about going directly to the chassis with the electromagnetic screen wire. I'll keep it in mind and maybe drill the required hole some day. Thanks for your constructive criticism, always welcome.
Thanks
It's a Dual CS 704 found at a nearby thrift store. It was 15€ iirc. It came with a Pickering XLZ/3500E cartridge, no usable stylus though, also no dust cover. I redid the internal signal wiring, re-capped the motor drive board and put a Grado Prestige Silver moving iron cart on it. Lovely table.Attachments
From aliexpress China, but it's also on ebay. The type number is JC2210. But it's a very tight fit for the boards, check the first pic of my post above, I had to drill into the rail of the side panel (and cut a thread) to mount a post there.
Finally finished my build today, massive snow storm in NE US, so a good time to wrap things up. Luckily I had some spare 9K resistors in my parts bin to sub in for R3X and they gave me the adjustment I needed to get the bias set dead on 3.6 v. Hooked everything up and played a few albums, Wow sounds as good as CD's ! Just kidding. I never has really nice gear back in the 70's when I was listening to albums on my Kenwood consumer goods, so this came as a big surprise to me how nice vinyl sounded. Listening through my old Shure V15 type IV ---> Aikido tube pre ---> Pass F6 sounds fantastic. Many thanks Salas for a great project.
Paul
Paul
Guys, I have now 2 FSP amp and I'm going to try to sale one for pure BOM parts price. It is fully assembled with custom Raw PSU board and I used it for about a year 3-4 hours each weekend. It is using Mundorfs SIO and Evo AlOil caps in shunt. All the rest of parts is what Salas recommended with PRP resistors and Vishay Naked. You just need to box it. Please PM me if interested.
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Hi Salas,
You are correct, it is a mains filter, I had it left over from a previous project, so what the heck, I threw it in on this one, it can't hurt. The speakers are diy back loaded horns that I made some years ago using Martin Kings great mathcad software. The drivers are Jordan JX92S full range, the tweeter was added, but not in use, sounds better without, and I never could get it to integrate to my liking. They are a great match for the F6 amp and are truely full range. For filters I'm using a zobel, and bsc bypassed by a cap to lift the high upper end.
Paul
You are correct, it is a mains filter, I had it left over from a previous project, so what the heck, I threw it in on this one, it can't hurt. The speakers are diy back loaded horns that I made some years ago using Martin Kings great mathcad software. The drivers are Jordan JX92S full range, the tweeter was added, but not in use, sounds better without, and I never could get it to integrate to my liking. They are a great match for the F6 amp and are truely full range. For filters I'm using a zobel, and bsc bypassed by a cap to lift the high upper end.
Paul
Also the metal sections (Mu?) and a magnetically shielded toroid type kept the mains hum out from the single box build. Well done.
Folded end to end we could say now. Folded cascode phono, folded horn speakers.
The phono sound will go up a notch in the next few days if you play it a bit more by the way.
Very good woodworking both in your speakers and phono box. Excellent overall interior style blending. Not even speaker cables to be seen.
Maybe a low pass on the Jordan in the last octave by 6dB slope could help integrate the tweeter (bullet?) or a ribbon crossed alone could be more compatible with the Jordan's HF beaming?
Folded end to end we could say now. Folded cascode phono, folded horn speakers.
The phono sound will go up a notch in the next few days if you play it a bit more by the way.
Very good woodworking both in your speakers and phono box. Excellent overall interior style blending. Not even speaker cables to be seen.
Maybe a low pass on the Jordan in the last octave by 6dB slope could help integrate the tweeter (bullet?) or a ribbon crossed alone could be more compatible with the Jordan's HF beaming?
Hi Andrew,
The higher noise levels aren't going to be dramatic at all. These will be close enough not to worry about.
You can measure the noise voltage directly using a DC blocking capacitor if your equipment can't handle any DC. Use a THD meter and compare residuals. It will be seen that the noise from slightly higher Vf LEDs is no concern at all unless you're into ultraviolet LEDs.
-Chris
The higher noise levels aren't going to be dramatic at all. These will be close enough not to worry about.
You can measure the noise voltage directly using a DC blocking capacitor if your equipment can't handle any DC. Use a THD meter and compare residuals. It will be seen that the noise from slightly higher Vf LEDs is no concern at all unless you're into ultraviolet LEDs.
-Chris
the 2.7uV to 4.6uV of noise from the white LEDs seems to show nearly 20dB more noise from the higher voltage LEDs.
Blue, White and UV LEDs are all UV with different phosphors to mimic the required "colour".
The IR, red, green , yellow, orange seem to be long wavelengths without the phosphors, nor without the high Vf.
Hi Salas,
In this room I really can't hear beaming, in this particular horn/baffle the high frequency power response appears to be surprisingly even. It might have a lot to do with the complex shape of the room and vaulted ceiling. I've been messing with them for years and they have never sounded as good as they do with the F6, the synergy is really good. I had been considering upgrading to the latest Jordan offering, or modifying things with a ribbon like Jim Griffin's design, but once I tweeked the filter and put in the F6 all those plans went out the window. I ended up with a 8R, 4.3uF zobel, 10R, 1.5 mH BSC bypassed with 1uF cap. I have a nice pair of 3 way speakers in my living room using scanspeak tweeters, peerless HDS mids and 10 "woofers to compare with and the Jordans don't obviously fall behind in the high end, and the horns have more punch and go lower in the low end, must be due to floor and corner loading. You can be certain that I will be going through my old vinyl with some good bourbon this afternoon.
Paul
In this room I really can't hear beaming, in this particular horn/baffle the high frequency power response appears to be surprisingly even. It might have a lot to do with the complex shape of the room and vaulted ceiling. I've been messing with them for years and they have never sounded as good as they do with the F6, the synergy is really good. I had been considering upgrading to the latest Jordan offering, or modifying things with a ribbon like Jim Griffin's design, but once I tweeked the filter and put in the F6 all those plans went out the window. I ended up with a 8R, 4.3uF zobel, 10R, 1.5 mH BSC bypassed with 1uF cap. I have a nice pair of 3 way speakers in my living room using scanspeak tweeters, peerless HDS mids and 10 "woofers to compare with and the Jordans don't obviously fall behind in the high end, and the horns have more punch and go lower in the low end, must be due to floor and corner loading. You can be certain that I will be going through my old vinyl with some good bourbon this afternoon.
Paul