is a 117 a new transistor?
I tried to put a bigger pic up and it wouldn't let me do it,,,,,I did what I could get up there ,The copper is showing on spencers ,
If you shrink the pic, it's a little bit better,I'll see if I can get a better pic to upload,the 2 on the right don't show copper but they checked/worked ok,so what do I know,lol.
Yea Buzz lots on ebay,I have bought real ones there too!
Thanks,
NS
I tried to put a bigger pic up and it wouldn't let me do it,,,,,I did what I could get up there ,The copper is showing on spencers ,
If you shrink the pic, it's a little bit better,I'll see if I can get a better pic to upload,the 2 on the right don't show copper but they checked/worked ok,so what do I know,lol.
Yea Buzz lots on ebay,I have bought real ones there too!
Thanks,
NS
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I was looking for 2sk170 and bj74's but thanks,Those are close 300mw instead of 400 m
Those are close 300mW instead of 400 mW what P comp goes with them?
NS
Those are close 300mW instead of 400 mW what P comp goes with them?
NS
I thought two things:
1) 29 V P-P should just read 29V peak.
2) 7.2 ought to be 7.25, but that's picky.
1) 29 V P-P should just read 29V peak.
2) 7.2 ought to be 7.25, but that's picky.
29V peak to peak. (P-P)
if i understand it correct.
29*29/4/2=105.125W
or
29*0.707=20.5V RMS
20.5*20.5/4=105.093W
marginal difference🙂
3.6A bias give us:
7.2*7.2*4/2=103.68W
or
7.2*0.707=5.09A
5.09*5.09*4=103.6W
correct me if i'm off. but explain it. (don't do a Andrew)
I completed 1 monoblock of the V2 turbo.
Bias (with output open, input shorted) is 360 mV and 8 mV offset.
I have one observation though
--When i plug in the DCB1 preamp (-1.2 mV offset), even with the preamp off i get a offset of -80mV from F5T. Goes back to 8mV when i unplug the input.
My Aleph J does'nt do that , with or without the preamp connected it gives me 25 mV offset.
Bias (with output open, input shorted) is 360 mV and 8 mV offset.
I have one observation though
--When i plug in the DCB1 preamp (-1.2 mV offset), even with the preamp off i get a offset of -80mV from F5T. Goes back to 8mV when i unplug the input.
My Aleph J does'nt do that , with or without the preamp connected it gives me 25 mV offset.
Any dc on the output of the preamp will change bias point of input Jfets, as they will see it as an additional voltage on their gate, and bias is ultimately determined by Vgs.. Add cap on outputof b1 or input of f5t and see what happens.
Thanks Buzz, but as i said with the preamp off (no DC) it still gives me -80mV.
I think that this is related to grounding in F5T (used the grounding scheme as suggested in F5T article-- that is using a 4 prong chassis mount diode and CL60). I must have done something wrong. I'll try the old scheme (no diode just the CL-60 in between the PSU ground and chassis ground) in the other channel.
But then again for the sake of testing, i connected the alpeh-j input (switched off) with F5T input (switched on) get 8mV F5T offset.
Connected DBC1 output (switched off) with F5T input (switched on) get -80mV F5T offset. This points that the F5T grounding is ok
Why cant i have easier issues (like mosfets blowing) :-D
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I don't know. When setting bias, do you short the input? Is the amp oscillating?
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Well i clip the AGND & IN wires with a alligator clip while biasing.
Cant tell about oscillation (no scope) but there is no unnecessary heating
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Don't know. Something is changing DC condition slightly. Double check all joints on connectors and inputs. See If you DMMnset on AC picks anything up when it is hooked up to the pre.
Should I need to repeat what I posted?
BigE could see it
But AudioS is so full of himself, he could not be bothered to actually read what he had typed and take on board the advice re confusion of voltage terms/units.
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Is there any audible hum at the speakers. If there is no hum and just 80mv offset, one should not worry. I hope you adjusted the bias and offset after reaching full temperature on the heatsinks.
that is much normal🙂 there is no input caps on the F5 to take care of the remaining ofsett. the alephs have this.
10times ofsett jump is normal. on the other hand. 80mV is not anything to loose any sleep over.
10times ofsett jump is normal. on the other hand. 80mV is not anything to loose any sleep over.
andrew. i hope you dont wright to me. then you are waising your time. you are on my ignore list now.
Hello Andrew.
could you please specify what is wrong. I don't see it 🙂
then again... I'm only here to learn so.......
set up the right formula for us, would you?
thanks