So you can change capacitors—shmapacitors, or practice your alcohol tolerance and boost up those 3.5% ;-)Don't expect any real sig changes in sound due to cap selection in this amp. You can leave off the cap on the neg input. Drive it with balanced signal or with negative leg and you got something wonderful. The topology defined 80% of the sound. Better PSU defines last 15%. Your blood alcohol level determines 3.5% of the sound, and the last 1.5% is passive parts choice
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No sure if this is the right thread ...
In the spirit of being universal ...
Just curious if anyone has built an "upside down" Aleph J;
using the more easily available and less risky to acquire dual N-JFET from Linear Systems (or a matched pair of singles) and flipping the polarity of all the other semis and caps as appropriate.
I think I saw in a related thread where someone paid almost $9 each for 2SJ74 - that seems a bit much to me ...
I'm just saying ...
mlloyd1
PS I might be showing my age again here
I know sometime in the past it was "preferred" to use P devices in front end because they were a little quieter and N devices in the next stage (VAS) because they were faster with lower capacitances. Semi processes have advanced a bit over the years and this is a power amp instead of a MC phono preamp.
In the spirit of being universal ...
Just curious if anyone has built an "upside down" Aleph J;
using the more easily available and less risky to acquire dual N-JFET from Linear Systems (or a matched pair of singles) and flipping the polarity of all the other semis and caps as appropriate.
I think I saw in a related thread where someone paid almost $9 each for 2SJ74 - that seems a bit much to me ...
I'm just saying ...
mlloyd1
PS I might be showing my age again here
I know sometime in the past it was "preferred" to use P devices in front end because they were a little quieter and N devices in the next stage (VAS) because they were faster with lower capacitances. Semi processes have advanced a bit over the years and this is a power amp instead of a MC phono preamp.
Aleph builder required reading: http://www.diyaudio.com/forums/pass-labs/12923-top-ten-ways-better-aleph.html
In all the Alephs I've built, I've always left R19 (R27 in AJ) open. It allows Q4 to run bias 'wide open'...generally increases overall bias by about 500mA. The resistor just trims the bias. But this connection in AJ scheme is slightly different, so I'm wondering if this same mod applies.
In all the Alephs I've built, I've always left R19 (R27 in AJ) open. It allows Q4 to run bias 'wide open'...generally increases overall bias by about 500mA. The resistor just trims the bias. But this connection in AJ scheme is slightly different, so I'm wondering if this same mod applies.
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No sure if this is the right thread ...
In the spirit of being universal ...
Just curious if anyone has built an "upside down" Aleph J;
using the more easily available and less risky to acquire dual N-JFET from Linear Systems (or a matched pair of singles) and flipping the polarity of all the other semis and caps as appropriate.
I think I saw in a related thread where someone paid almost $9 each for 2SJ74 - that seems a bit much to me ...
I'm just saying ...
mlloyd1
PS I might be showing my age again here
Mlloyd,
I have some dual die N channel samples coming that I plan to try in a preamp with a similar configuration. Not difficult to try other options and sooner or later the J74 will be extinct. Nelson has stated that they are not necessary in power amps anyway, being more important in line level and low noise designs.
Would be even better if it were the original Toshibas, desoldered from the beast with the 10.000 JFets
Would be even better if it were the original Toshibas, desoldered from the beast with the 10.000 JFets
I think they left the leads long enough in the Beast that the FETs could be clipped out if they ever needed to be harvested.
This is what the website of Linear Systems says:
What would be a new year without new products? In 2013, we will be introducing three new products, all of which are JFETs specifically designed for the professional audio markets: LSK489, LSJ74, and LSK186.
I hope the diyAudio store can deliver the LSJ74's