Actually, looking at the drawing better, I've noticed the wire that connects the network in the middle!
Indeed! I've also found some spare .47 and .68 resistor. Good. I'll give a go and report here.
Thanks!
It will cost a bit output power on an already low-power amp. It's worth a try, however, if your speakers are of suitable efficiency.
Hey all!
I've finally mounted everything on 2 veroboards (both channels) and .... sounds awesome
Complete winner, 2k2 mod of course running @20 volts SMPS. Tough I have a ~24volts (rectified and ripple-regulated) linear supply that I'm gonna use soon.
@6L6: indeed, I might also give a go to this mod.
I find this amp in general powerful enough for my room, consider that I'm not using high-end spearkers of any sort (8 ohms).
Sound is very clean and I very much like basses.
Overall completely satisfied: my motto is something around the words "If it's yours, then it must sound good either way"
...but this really sounds sweet hihi
I've finally mounted everything on 2 veroboards (both channels) and .... sounds awesome
Complete winner, 2k2 mod of course running @20 volts SMPS. Tough I have a ~24volts (rectified and ripple-regulated) linear supply that I'm gonna use soon.@6L6: indeed, I might also give a go to this mod.
I find this amp in general powerful enough for my room, consider that I'm not using high-end spearkers of any sort (8 ohms).
Sound is very clean and I very much like basses.
Overall completely satisfied: my motto is something around the words "If it's yours, then it must sound good either way"
...but this really sounds sweet hihi
My AP System 1 is has a slight problem so the graphs it produces now don't correlate with earlier measurements. In general the 1KHz THD vs Power graph is pushed down to about half the THD with the 2.2K mod. If you look at THD vs Frequency however, the improvement is only below about 2KHz. At 10KHz there is a small increase in THD. See the graph in post 713.
Setting the quiescent output voltage is a little different with the 2K2 mod. I found that setting Q1's Drain to 9.2V gave the cleanest looking graph with a 19.0V rail. The 19V power supply bricks I've looked at are around 19.5V. Premature clipping on one rail causes a lump in the THD vs PWR graph above 3 Watts or so.
Has anyone tried different enhancement mode parts and the ACA?
I was thinking to change out both Q1 and Q2.
Quote:
" These elements are chosen to control Q2 in such a way that it acts as a DC constant current source which also varies AC-wise so as to favorably help the amplification provided by Q1."
My interpretation is that Q2 does double duty as current source, and helps the circuit "AC-wise" and that it has an overall effect on the sound.
Is SJEP120R100 for both Q1 and Q2 feasable? with a slight change in current source bias? Or just changing Q2 to a enhancement JFET?
I have a diy F2J for comparison.
Thanks.
I was thinking to change out both Q1 and Q2.
Quote:
" These elements are chosen to control Q2 in such a way that it acts as a DC constant current source which also varies AC-wise so as to favorably help the amplification provided by Q1."
My interpretation is that Q2 does double duty as current source, and helps the circuit "AC-wise" and that it has an overall effect on the sound.
Is SJEP120R100 for both Q1 and Q2 feasable? with a slight change in current source bias? Or just changing Q2 to a enhancement JFET?
I have a diy F2J for comparison.
Thanks.
Thanks Loudthud, that's a great comparison and it came before the mod was discussed so that's why I didn't see it. My Q1 is still set at 10v using the bricks that came with the kit. I'm very happy with these amps paired with my Hornshoppe horns.
I left 1ch of the ACA plugged in and turned overnight/ maybe 1 full day and now the sound that comes from it is very distorted. Where would you begin looking? I tried swapping out PSU walwarts but that wasn't the culprit.
I am going to take it apart to test tomorrow. Figured someone could give me a clue. Im not familiar with this amp like I am with the Aleph amp.
Thank you,
Steve
I am going to take it apart to test tomorrow. Figured someone could give me a clue. Im not familiar with this amp like I am with the Aleph amp.
Thank you,
Steve
yup
just feed it with balanced signal , take outs from hots and voila!
@hip - I just woke up , 45min ago
Thank you Sir
Regards
Sachin
Ok fair enough that explains why you are always first on my replies
Zen I will post measurements of V over source R's, and numbers @ mosfets G,D,S, etc
Anything else to measure? I am going to recheck all connections also, thinking could be a cold solder or ground issue, but I am off to bed now.
Steve
Zen I will post measurements of V over source R's, and numbers @ mosfets G,D,S, etc
Anything else to measure? I am going to recheck all connections also, thinking could be a cold solder or ground issue, but I am off to bed now.
Steve
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