Pass DIY Addict
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Amazing work! I thought I recognized those Seifert heatsinks! What are the physical dimensions of the sinks?
Thanks for the comparison! If you have the time, I'd be interested to see the 4ohm plots your XA160 (I assume this is your DIY version?).
Yes, my DIY version.
Here we go
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Pass DIY Addict
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Thanks for the graph, JBL4435. I appreciate you taking the time to do this. Curious the dip and then the quick rise again as power increases... I've heard a number of people comment about lower distortion after changing the IRFP9610 front end to JFETs. I wonder if this makes a dramatic a visual difference...
Yes ... why such a sharp rise after 20W output ....
I'll change the graph to logarithmic X-Axis. Then it will look more familar with distortion plots from let's say stereophile.
I'll do this later
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I'll change the graph to logarithmic X-Axis. Then it will look more familar with distortion plots from let's say stereophile.
I'll do this later
Interesting, I didnt expect distortion to be so high.
Dream Amps
While we have this discussion about distortion I want to point out that I LOVE my AX amps. They do sound wonderful and better than everything I heard before!!
I don't think that the AX amps have that high distortion for it's design. The Aleph design was made for SOUND and not for measuring.
I started this measurements only out of curiousity when I got an HP Audio Analyzer.
While we have this discussion about distortion I want to point out that I LOVE my AX amps. They do sound wonderful and better than everything I heard before!!
I don't think that the AX amps have that high distortion for it's design. The Aleph design was made for SOUND and not for measuring.
I started this measurements only out of curiousity when I got an HP Audio Analyzer.
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Thanks for the compliment.
the rail voltage is +/- 15,5V 7A I use 8 FETs . It is enough, really.
CLC 100.000µF + 2,2mH (0,12 Ohm) + 100.000µF
I use a pair of martin logan request and need very much current (7A).
Hi
what Is the toroid that you have used
While we have this discussion about distortion I want to point out that I LOVE my AX amps. They do sound wonderful and better than everything I heard before!!
I don't think that the AX amps have that high distortion for it's design. The Aleph design was made for SOUND and not for measuring.
I started this measurements only out of curiousity when I got an HP Audio Analyzer.
It was merely an observation based on comparisons with other high end amp distortion measurements. It was not a judgement on the quality of these amps🙂
Hi
what Is the toroid that you have used
I orderd the toroids from Schuro. They are special made for me.
2 x 13V / 600VA
thank you
are they low noise
Yes, normally they are very quiet. I tested it with a normal load outside of the case and their was no noise. Absolut quiet.
But with the Aleph-X the current is in the first 15 minutes much higher than if it is becomes warm.You must know i have in my aplication very high charging current peaks about 50A.
If it is cold i hear the toroids a little bit. 15 minutes or 20 minutes later they are silent.
You only can hear it if you go with your ear in the case.
Distortion Balanced in
So, these will be the last THD Plots.
I finally finished my BNC-XLR input cable 😛
THD seems not to change much with balanced or unbalanced in
1st: DIY XA160 8 Ohms load, Balanced in
2nd: DIY XA160 4 Ohms load, Balanced in
3rd: DIY XA160 4 Ohms load, Un-Balanced in
So, these will be the last THD Plots.
I finally finished my BNC-XLR input cable 😛
THD seems not to change much with balanced or unbalanced in
1st: DIY XA160 8 Ohms load, Balanced in
2nd: DIY XA160 4 Ohms load, Balanced in
3rd: DIY XA160 4 Ohms load, Un-Balanced in
Attachments
I am surprised there is any difference if your BNC-XLR cable doesn't include a transformer or other single ended to balanced converter. Sounds like you're still feeding your amp a single ended signal, the only difference is where the negative input gets grounded. Try feeding your amp from a balanced preamp. You should see some difference.
I am surprised there is any difference if your BNC-XLR cable doesn't include a transformer or other single ended to balanced converter. Sounds like you're still feeding your amp a single ended signal, the only difference is where the negative input gets grounded. Try feeding your amp from a balanced preamp. You should see some difference.
I know how to make an 2xBNC to XLR adapter. Would I be able to build an AX amp if not? 🙂
I feed my amp from the balanced output of a HP8903B audio analyzer.
Oops. Didn't realize it was a 2x BNC input. Would have expected a bit more difference in distortion.
Oops. Didn't realize it was a 2x BNC input.
Me DUMMY didn't post it right 😱
Pass DIY Addict
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I have been trying to increase the input sensitivity of my Aleph-X amps. I discovered that it takes nearly 2.5v RMS input signal in order to drive my amps to full output. All of my other amps (Marantz, Adcom, Behringer) all hit full volume output with input more on the order of 1.0 to 1.2v RMS. So I would like to increase the input sensitivity of my Aleph-X amp. I'm driving it with the RCA input and the appropriate pins on the XLR input are jumpered.
I following the advice that I found here: http://www.diyaudio.com/forums/pass-labs/98327-anyone-tried-up-aleph-x-input-impedance.html
Using the schematic linked here: http://www.facstaff.bucknell.edu/esantane/movies/axschem.jpg
I made the following changes:
Change R18 from 10k to 20k ohms
Change R19 from 10k to 20k ohms
Change R16 from 100k to 200k ohms
I didn't have any smaller values in my box of spare parts, so I left C2 unchanged at 3pF. I changed each of the complimentary resistors on the other side of the circuit board as well.
These changes seem to have made no difference.
Why didn't this increase the input sensitivity of my amp? Any insights?
Thanks,
Eric
I following the advice that I found here: http://www.diyaudio.com/forums/pass-labs/98327-anyone-tried-up-aleph-x-input-impedance.html
Using the schematic linked here: http://www.facstaff.bucknell.edu/esantane/movies/axschem.jpg
I made the following changes:
Change R18 from 10k to 20k ohms
Change R19 from 10k to 20k ohms
Change R16 from 100k to 200k ohms
I didn't have any smaller values in my box of spare parts, so I left C2 unchanged at 3pF. I changed each of the complimentary resistors on the other side of the circuit board as well.
These changes seem to have made no difference.
Why didn't this increase the input sensitivity of my amp? Any insights?
Thanks,
Eric
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just double values of R16 and R30
leave everything else original
recheck offsets and for oscillation
leave everything else original
recheck offsets and for oscillation
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