In terms of "audiophile" components this is what I used:
1) Overated trafos at 2x120VA instead of 2x60VA
2)Ultra fast soft recovery diodes for rectification (IRF)
3)Aerovox and Black Gate caps for the power supply boards.
4)Sikorel 2200uF caps under the main PCB
5)Holco non-magnetic resistors
6)Dedshete damping sheets to minimise chassis ringing and decouple PCB's
7)Silver-plated hook-up wire from Audio-note.
8)DACT gold plated stepped attenuator and selector switch.
Further mods may include replacing film coupling caps with Black Gate BG N non-polar as advised by Peter Qvortrup of Audio-note.
Perhaps bypassing Sikorel caps with film and film+foil caps.
Now to the sound of this sexy little bride of my Aleph 5's.
At first I only heard it unbalanced in and out for a few days.Compared to my passive set-up which is very transparent I didn't notice any loss of transparency which is quite a feat if you think how many more connections and active parts the signal goes through. There was a much more powerful dynamic sound especially in the bass which was what I was hoping for. Of course pace and timing were also much better.However with all the extra dynamics and punch there was a subliminal residual feeling of a bit of hardness on some recordings around the midrange. I didn't know if this was because my passive set-up was softening the recordings and that the BOSOZ was showing more of the deficiencies of some recordings or that it was adding something of it's own.
Then one day I wired up the balanced connection in the Alephs and switched on.
Well , with the first few seconds of music my jaw dropped, I started rubbing my eyes and pinching myself in case I was dreaming because I wasn't sure I was listening to the same system , much less the same pre-amp!
Well allright, maybe I am exaggerating a teeny bit but we are fanatics aren't we?
Seriously I thought that my speakers had "grown" much bigger even taking into account some small level differences. Everything was there but more of it. The soundstage expanded and deepened cosiderably, there was more space between instruments and the bass got even better!And on top of it all everything sounded more natural with that residual hardness completely gone.
In I am completely in love with balanced operation.Just to give you an idea I tried also balanced in from my TEAC VRDS-25 CDP and it actually sounded a bit better than my unbalanced Perpetual Technologies P3A-P1A-Monolithic PS which usually mops the floor with it. The Teac is clocked and op-amped but the P.T. combo is also op-amped with OPA627's and with soft recovery diodes and is generally regarded as close to state of the art for DAC's (as well as being almost twice as expensive as the CDP) I am annoyed now that I can't get balanced operation from it because it doesn't seem to be a dual differential circuit.
1) Overated trafos at 2x120VA instead of 2x60VA
2)Ultra fast soft recovery diodes for rectification (IRF)
3)Aerovox and Black Gate caps for the power supply boards.
4)Sikorel 2200uF caps under the main PCB
5)Holco non-magnetic resistors
6)Dedshete damping sheets to minimise chassis ringing and decouple PCB's
7)Silver-plated hook-up wire from Audio-note.
8)DACT gold plated stepped attenuator and selector switch.
Further mods may include replacing film coupling caps with Black Gate BG N non-polar as advised by Peter Qvortrup of Audio-note.
Perhaps bypassing Sikorel caps with film and film+foil caps.
Now to the sound of this sexy little bride of my Aleph 5's.
At first I only heard it unbalanced in and out for a few days.Compared to my passive set-up which is very transparent I didn't notice any loss of transparency which is quite a feat if you think how many more connections and active parts the signal goes through. There was a much more powerful dynamic sound especially in the bass which was what I was hoping for. Of course pace and timing were also much better.However with all the extra dynamics and punch there was a subliminal residual feeling of a bit of hardness on some recordings around the midrange. I didn't know if this was because my passive set-up was softening the recordings and that the BOSOZ was showing more of the deficiencies of some recordings or that it was adding something of it's own.
Then one day I wired up the balanced connection in the Alephs and switched on.
Well , with the first few seconds of music my jaw dropped, I started rubbing my eyes and pinching myself in case I was dreaming because I wasn't sure I was listening to the same system , much less the same pre-amp!
Well allright, maybe I am exaggerating a teeny bit but we are fanatics aren't we?
Seriously I thought that my speakers had "grown" much bigger even taking into account some small level differences. Everything was there but more of it. The soundstage expanded and deepened cosiderably, there was more space between instruments and the bass got even better!And on top of it all everything sounded more natural with that residual hardness completely gone.
In I am completely in love with balanced operation.Just to give you an idea I tried also balanced in from my TEAC VRDS-25 CDP and it actually sounded a bit better than my unbalanced Perpetual Technologies P3A-P1A-Monolithic PS which usually mops the floor with it. The Teac is clocked and op-amped but the P.T. combo is also op-amped with OPA627's and with soft recovery diodes and is generally regarded as close to state of the art for DAC's (as well as being almost twice as expensive as the CDP) I am annoyed now that I can't get balanced operation from it because it doesn't seem to be a dual differential circuit.
Hello protos,
Nice layout.
I like the blue LED and your cone stands.
Try to make selector and volume pot knobs out of wood,
with little larger diameter, they will look even more awsome.
Why you did not use filter capacitors on the main PCB ?
The circuit will perform even better with them.
Best regards,
Kristijan Kljucaric
http://web.vip.hr/pcb-design.vip
Nice layout.
I like the blue LED and your cone stands.
Try to make selector and volume pot knobs out of wood,
with little larger diameter, they will look even more awsome.
Why you did not use filter capacitors on the main PCB ?
The circuit will perform even better with them.
Best regards,
Kristijan Kljucaric
http://web.vip.hr/pcb-design.vip
Hello,
Never mind for the capacitors.
I just saw them under the PCB.
Best regards,
Kristijan Kljucaric
http://web.vip.hr/pcb-design.vip
Never mind for the capacitors.
I just saw them under the PCB.
Best regards,
Kristijan Kljucaric
http://web.vip.hr/pcb-design.vip
There are a couple of things I forgot to mention:
The trafos are shielded with ìu-metal.You will notice the tie-wraps around them.
Regarding some interest that was expressed about using the BOSOZ as a headphone amp I have to report that despite Nelson's assertion in a related thread that BOSOZ is suitable it seems it may not in fact have enough gain.
Using the 10db gain model I was unable to get enough gain at all.Going up to the 20db gain (120 ohm R15) there was just enough gain when the volume was fully open.This was with single ended use. With balanced input the gain was a little bit higher of course and I could back off on the volume.The funny thing is that it seems the output drops quite obviously into low impedances (Nelson does mention this) and at a certain range as you increase the volume control you don't get more output until the very last setting which suddenly seems to double in loudness.
Apart from the above considerations the quality of sound I am getting driving the headphones fully balanced (I had to make special RCA connectors for each channel) is quite thrilling.
Thanks everybody for the nice comments.This is only my second attempt at DIY after the Alephs and I feel I am starting to get the hang of it.
Kristijan your boards are a big help but I disagree on the wooden knobs suggestion.Apart from the fact that they would be difficult to attach to the spindles I think the black anodised aluminium knobs on the wood fascia echo the rest of the design.
I think combining wood with wood would become too rustic. However I love the retro-modern aesthetic of real wood with aluminium that you see in Scandinavian or modern Japanese design.Moreover I think the balanced combination of soft vs hard, organic vs inorganic,light vs dark represents the yin-yang design philosophy of the differential and balanced BOSOZ.
The trafos are shielded with ìu-metal.You will notice the tie-wraps around them.
Regarding some interest that was expressed about using the BOSOZ as a headphone amp I have to report that despite Nelson's assertion in a related thread that BOSOZ is suitable it seems it may not in fact have enough gain.
Using the 10db gain model I was unable to get enough gain at all.Going up to the 20db gain (120 ohm R15) there was just enough gain when the volume was fully open.This was with single ended use. With balanced input the gain was a little bit higher of course and I could back off on the volume.The funny thing is that it seems the output drops quite obviously into low impedances (Nelson does mention this) and at a certain range as you increase the volume control you don't get more output until the very last setting which suddenly seems to double in loudness.
Apart from the above considerations the quality of sound I am getting driving the headphones fully balanced (I had to make special RCA connectors for each channel) is quite thrilling.
Thanks everybody for the nice comments.This is only my second attempt at DIY after the Alephs and I feel I am starting to get the hang of it.
Kristijan your boards are a big help but I disagree on the wooden knobs suggestion.Apart from the fact that they would be difficult to attach to the spindles I think the black anodised aluminium knobs on the wood fascia echo the rest of the design.
I think combining wood with wood would become too rustic. However I love the retro-modern aesthetic of real wood with aluminium that you see in Scandinavian or modern Japanese design.Moreover I think the balanced combination of soft vs hard, organic vs inorganic,light vs dark represents the yin-yang design philosophy of the differential and balanced BOSOZ.
I haven't really worked it out but I will mention some of the most expensive items.The rest are mainly standard componennts.
Dact attenuator and selector kits: 280 Euro
Sikorel capacitors: 100 E
Anodised alu case : 100 E
Pcb boards : 90 E
IRF diodes : 40 E
Trafos : 55 E
The aerovox ,bg caps were not a big dent neither the holco resistors but in the end everything adds up doesn't it?
Of course you can make big savings by using more standard pots and selector like Alps , simpler PS,make your own case and boards and forgo the more exotic components but I decided to max it. I still wonder how a bog standard BOSOZ would sound compared to what I did.
Dact attenuator and selector kits: 280 Euro
Sikorel capacitors: 100 E
Anodised alu case : 100 E
Pcb boards : 90 E
IRF diodes : 40 E
Trafos : 55 E
The aerovox ,bg caps were not a big dent neither the holco resistors but in the end everything adds up doesn't it?
Of course you can make big savings by using more standard pots and selector like Alps , simpler PS,make your own case and boards and forgo the more exotic components but I decided to max it. I still wonder how a bog standard BOSOZ would sound compared to what I did.
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