I once used a coax based patch cord that was left over from a custom install at a relatives house and it severity attenuated the bass response from the CD player in my system, it was due to the capacitance of the wire, or atleast that is what I was told. Not sure if this may be helpful in this situation but it may explain the overly bright sound, or thinking another way, less bass response?
Funny you say that. Read this article last week. This is in regards to a Spectral amp, midday in the article
Gramophone Dreams #30: Skyfi Audio Page 2 | Stereophile.com
not wanting to be nitpicky - 25Vdc caps are good in my book , with 18Vac secondaries , resulting in 22-23Vdc under load
as long as caps are of good quality , and aren't popped , as wise xbit confirmed
so , just chill , replace that nasty wiring .......
Reporting back - in case some else will run to similar problems like me.
First, Aleph finally sounds sweet and mellow.
I made the following changes:
1. thicker output wire (thanks ZM!)
2. more efficient speakers (thanks aljordan!)
3. single-ended output from RME ADI-2 instead of balanced one(thanks jf4828!)
4. removed output snubbers from PSU(thanks 6L6!).
Not sure which change helped - did not retest after every change unfortunately.
Anyway, thanks everyone for a great help!
Thanks! Actually I cannot stop listing to it. The sound of Aleph is really addictive....
I second this. "Finished" my AJ build last week... been running it against my F5 as well.
AJ is 100% the amp for me (so far!). Sounds INCREDIBLE.
I had/have some AJ buzz—very similar to F5 buzz that's been covered a bit in the F5 thread—had lots of help there and rebuilt it to ZM specs. I was able to cut the AJ buzz (Initially had more buzz than my "fixed" F5, which still has some buzz) in half by live rotation of the transformer—could literally tune it softer—and careful routing of input and output wires—they didn't like being anywhere hear the PSU/over caps... I'll post some pics soon—I'm going to install some HBRs first (6L6!!!!!).
My question... is about something I observe when powering the amp off and I want to know if it's normal. When I flip the AJ off—I get a little thump in the left channel only (I know that's not a biggie)—the PSUs left LED goes out immediately—and the right PSU LED stays lit for a nice protracted bleed out... The V- LEDs from BOTH amp PSBs also stay lit and bleed out with the PSU—I ran V- LEDs to the front panel...
Incidentally... It seems to be running on the cool side of AJ. Getting about 114F on the sinks—119F or so on the mosfets. It's in a 400mm 3U...Mosfets are very low in position on the sinks...
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Do you use a single power supply PCB, or 2 power supply PCB's? Is the LEFT LED a negative rail LED... or positive rail LED?
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Thanks Jim!
Single PSU, DIY Audio store version. V+ rail discharges immediately....
When you turn the power OFF (and due to the fact that amp is DC coupled to speakers), the CCS transistor will detect the drop in current (through R20-R23) as a change in AC amplitude (very low frequency). The current will start rushing through the R25/R26, which will, in turn, open the Q5 and Q6 more, contributing to a rapid discharge of + DC rail.
I am not sure why the need for such a large cap in C3 position.... reducing its value may help with turn off thump... C3 is there to allow CCS transistor to provide AC gain, but why such a large value? Also, the point where the R16/R17 meet the Q7/Q8 will at the same time change its DC potential level, which will influence the whole thing.... I suppose the only way would be to experiment... a bit... in an attempt to reduce the turn off thump, but the question is... is it really a problem. It seems in your case it is not.
I am not an expert...maybe someone will chime in... it would be nice to see what others think
I am not sure why the need for such a large cap in C3 position.... reducing its value may help with turn off thump... C3 is there to allow CCS transistor to provide AC gain, but why such a large value? Also, the point where the R16/R17 meet the Q7/Q8 will at the same time change its DC potential level, which will influence the whole thing.... I suppose the only way would be to experiment... a bit... in an attempt to reduce the turn off thump, but the question is... is it really a problem. It seems in your case it is not.
I am not an expert...maybe someone will chime in... it would be nice to see what others think
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I'm about to start my Aleph J build and am curious about the suggestion to remove the snubbers from the PS. What is the reasoning and is it a general rule when building an AJ?
Thanks.
genechow I think if you study the schematic of the Universal PSU PCB from the store, you will find that it contains a total of four snubbers. Two of them are "input snubbers" and two of them are "output snubbers". I believe member 6L6 advised member xbitwise not to populate the "output snubbers".
And this is highly recommended reading and a fun project regarding input snubbers if building the diode bridge portion of the DIY PSU (thanks to Mark!):
Simple, no-math transformer snubber using Quasimodo test-jig