Here are the pictures at last of my Aleph 5 monos. Although not as pro looking as some constructions I've seen at Pass diy and here I am quite proud of them considering a complete lack of electronic diy experience. Many thanks to all for their help. Thanks Mr.Pass for sharing. Without this very informative and encouraging site I would never have attempted this.
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protos said:
Nice to see another Aleph finshed! Nice going! Love the feet!
Perhaps you can up the bias a bit with so much heatsink! Are those perpetual P1 and P3 DAC's in your rack? How do they sound with the Aleph? What loudspeakers are you using?
I always like the look of a blue led in grey front!
Edwin
Thanks for the nice comments guys.
Here is some extra info. The ps is under the main board and is 500va trafo 2 bridges 2x47000uf Aerovox caps (no bypass).OFC cabling and Audio Note silver coated input wiring and input output connectors.Black Gate electrolytics. Brass screws for the fets.The values for bias are kept as per original x3 plan only I have x4 so I guess I do have more oomph probably around 2.1/2.2 amps bias per side. Heat sinks are running at about 45C although the fets measure much higher if you measure directly on center pin so I would hesitate to bias them even higher.Does anyone know what the maximum temperature is for these fets under reasonable conditions? The amps are very quiet even without extra ps filters. I have to put my ear practically right up to my 90 db Zingali Overture 3 horn/hybrid speakers to hear any noise. However I do seem to have some noise when connecting the input but I guess that is a system grounding problem.
Credit is due to Kostas Vazakas who is featured in the Pass diy gallery and who was so kind as to send me his pcb design seeing that I have no clue how to design a proper pcb. Unfortunately his measurements did not fit with my transformer width so I ended up using those two extra strips of aluminium between the angled extrusion and the heat sink . I still am not completely satisfied with the look of the aluminium. It scratches easily and when I tried to polish it with a polisher and cream it doesn't polish evenly.I tried to experiment with brushing but that doesn;t have an even look to it either.
I am using the perpetual P1-P3+ power supply with a Teac VRDS 25(clocked) as transport (regarded as one of the best transport mechanisms- I think Wadia use them). I will be upgrading the op-amps to BB opa627 within the next couple of days. I am very satisfied with this combination and I think it is a bargain for the price.
Here is some extra info. The ps is under the main board and is 500va trafo 2 bridges 2x47000uf Aerovox caps (no bypass).OFC cabling and Audio Note silver coated input wiring and input output connectors.Black Gate electrolytics. Brass screws for the fets.The values for bias are kept as per original x3 plan only I have x4 so I guess I do have more oomph probably around 2.1/2.2 amps bias per side. Heat sinks are running at about 45C although the fets measure much higher if you measure directly on center pin so I would hesitate to bias them even higher.Does anyone know what the maximum temperature is for these fets under reasonable conditions? The amps are very quiet even without extra ps filters. I have to put my ear practically right up to my 90 db Zingali Overture 3 horn/hybrid speakers to hear any noise. However I do seem to have some noise when connecting the input but I guess that is a system grounding problem.
Credit is due to Kostas Vazakas who is featured in the Pass diy gallery and who was so kind as to send me his pcb design seeing that I have no clue how to design a proper pcb. Unfortunately his measurements did not fit with my transformer width so I ended up using those two extra strips of aluminium between the angled extrusion and the heat sink . I still am not completely satisfied with the look of the aluminium. It scratches easily and when I tried to polish it with a polisher and cream it doesn't polish evenly.I tried to experiment with brushing but that doesn;t have an even look to it either.
I am using the perpetual P1-P3+ power supply with a Teac VRDS 25(clocked) as transport (regarded as one of the best transport mechanisms- I think Wadia use them). I will be upgrading the op-amps to BB opa627 within the next couple of days. I am very satisfied with this combination and I think it is a bargain for the price.
Hi Grip,
The Aleph sounds more natural in the mid high frequencuies and has a deeper soundstage than my Naim 250. It's pretty close in the bass department. Dynamics and timing of the Naim are of course very good but as the Aleph is breaking in (about 50 hrs now-can't break it in all day cause of WAF problems) I find it is very close. I've heard that Black Gates take forever to break in so will wait before doing an extensive A/B comparison.
I listen to a lot of stuff but mainly jazz,R&B, latin-cuban, reggae,mainstream rock, some classical etc. I don't particularly like listening to dance or techno unless I'm in a club with a few drinks inside and boogeying
The Aleph sounds more natural in the mid high frequencuies and has a deeper soundstage than my Naim 250. It's pretty close in the bass department. Dynamics and timing of the Naim are of course very good but as the Aleph is breaking in (about 50 hrs now-can't break it in all day cause of WAF problems) I find it is very close. I've heard that Black Gates take forever to break in so will wait before doing an extensive A/B comparison.
I listen to a lot of stuff but mainly jazz,R&B, latin-cuban, reggae,mainstream rock, some classical etc. I don't particularly like listening to dance or techno unless I'm in a club with a few drinks inside and boogeying
Gia sou megale ise kai o ...Protos. 
Very nice amps. They look very good. Why don´t you send some pictures to www.passdiy.com
I can´t wait to finish mine. They should be ready in the next month.
Very nice amps. They look very good. Why don´t you send some pictures to www.passdiy.com
I can´t wait to finish mine. They should be ready in the next month.
protos said:
One way to avoid overheating mosfets (and make a good use of your big heatsinks) would be changing the angles for thicker ones (3/16 or 1/4"). Also using thermal paste between . This spacer, although good for now, isn't recommended in the long run.
As to finishing aluminum check this thread: http://www.diyaudio.com/forums/showthread.php?s=&threadid=3981&perpage=15&pagenumber=4
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