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Old 31st August 2009, 08:53 PM   #11
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Its hard to see cos the pics are a little out of focus, but it kind looks like you have the jfets reversed? Its probably just the blurry pic, but thought I'd say it anyway........ yes, you guessed it, guess what I did with my first attempt at building!!

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Old 31st August 2009, 09:29 PM   #12
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Hi Fran,

The fet's flat faces are both pointing toward each other.
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Old 31st August 2009, 09:34 PM   #13
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Quote:
Originally Posted by vdi_nenna View Post
Can I go up to 3.3k on the R3 & R4 resistors?
Who will stop you?

When you measured those JFETs, what do you mean by
.29 and .18 ?
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Old 31st August 2009, 09:41 PM   #14
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OK, not familiar with the cviller boards (I built Peter Daniels ones) but I take it from your reply you have them the correct way around. Anyway, I'm only throwing out crumbs here. The master is speaking.......


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Old 31st August 2009, 10:12 PM   #15
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Quote:
When you measured those JFETs, what do you mean by
.29 and .18 ?
The .29 and .18 values are from the Idss matching when I built the B1.
I have jfets with higher Idss values.

I'll throw in a few 3.3k and see what happens. Just wanted to be sure I wouldn't make things worse by changing the relationship between the 5k pot and R3 and 4. Then again...how bad can it get?

Thanks!

V~
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Old 31st August 2009, 10:18 PM   #16
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You should get values like 5 to 10 milli-amps. What
do you suppose .18 or .29 is?
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Old 31st August 2009, 11:17 PM   #17
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Doh! I suppose I screwed up rather badly is what that is.
I was measuring DC instead of current.
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Last edited by vdi_nenna; 31st August 2009 at 11:29 PM.
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Old 31st August 2009, 11:41 PM   #18
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Well, that might mean that you haven;t matched them, but dosen't mean that they are not working! i had mine in backwards but no harm done to them.

The Q5 and Q6 - yours look really flat like ztx parts. but IIRC, cviller boards were made for BC550/560. If thats the case, maybe the pinout is different?

Just clutching at straws here.


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Old 31st August 2009, 11:47 PM   #19
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Yeah, see here:

http://www.diyaudio.com/forums/showp...&postcount=258

I remember it cos the ztx parts are hard enough to find in Europe.


Fran
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Old 1st September 2009, 12:07 AM   #20
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Yes, I used the ZTX450 and 550. They were to go in backwards compared to the BC transistors.

Quote:
Well, that might mean that you haven;t matched them, but dosen't mean that they are not working!
My B1 sounds fine. By "fine" I mean sweet!
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