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PeeCeeBee V4H GB

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J

J.M.K

Member
Joined 2009
shaan said:
I get infinite R on all terminals, except for SGND where I get 41MOhm (next to infinite on my DMM)


This is a potential source of the problem. It should read infinite as all the other terminals, because compared to the other terminals this one has the lowest area of copper trace, so even if the other terminals gave 41Mohm this one should give infinite. Check the insulation, also see if there is any component leg under the board that is very close to the heatsink. Cut it short.

I have an oscilloscope. How should I proceed ?
Amp powered up, and checking on OUT with a probe ?

Yes.
Click to expand...

Hurrah !!!!!!!! I just found what's wrong:
the insulation pad between Q12's back and the heatsink was slightly misplaced
and whilst fastening Q12, the brim of its metal back would come too close to the heatsink.

I'm going to simply replace this pad and everything should be fine.

One suggestion though, maybe you could mention on the setup manual
that simple checking to perform when the board is fasten to the heatsink,
one should check continuity between every terminal and the heatsink,
and that should measure infinite/Out Limit.

Thanks for your precious help.

JM
 
shaan

shaan

Member
Joined 2009
J.M.K said:
Hurrah !!!!!!!! I just found what's wrong:
the insulation pad between Q12's back and the heatsink was slightly misplaced
and whilst fastening Q12, the brim of its metal back would come too close to the heatsink.

I'm going to simply replace this pad and everything should be fine.

One suggestion though, maybe you could mention on the setup manual
that simple checking to perform when the board is fasten to the heatsink,
one should check continuity between every terminal and the heatsink,
and that should measure infinite/Out Limit.

Thanks for your precious help.

JM
Click to expand...

Hi JM.

Glad to know you found a potential solution. Waiting for test report.

The short connection test between output terminal and heatsink is already mentioned in point b of Preliminary Steps in Section 2 (page 3) in the setup guide. I will add the reminder to check the remaining 4 terminals as well. :)
 
J

J.M.K

Member
Joined 2009
This VH4 is a pure wonder.

I don't have very sophisticated measurement tools, Instek function generator, and Tektronix TDS 200 oscilloscope, everything seemed fine.
And I finally installed it in place of my First One 1.4M
What can I say. It has less gain than the FO,
BUT still a huge headroom for my speakers,
AND much better sound at every level,
more natural, more punchy, overall much better ....

I still have some work to perform on the enclosure,
and very much motivated to finish.
The FO will move to my TV system.

Thanks a lot for this gem.

JM
 
Bassivus

Bassivus

Member
Joined 2004
J.M.K said:
This VH4 is a pure wonder.

I don't have very sophisticated measurement tools, Instek function generator, and Tektronix TDS 200 oscilloscope, everything seemed fine.
And I finally installed it in place of my First One 1.4M
What can I say. It has less gain than the FO,
BUT still a huge headroom for my speakers,
AND much better sound at every level,
more natural, more punchy, overall much better ....

I still have some work to perform on the enclosure,
and very much motivated to finish.
The FO will move to my TV system.

Thanks a lot for this gem.

JM
Click to expand...

:cool: can't wait to make mine. Also as substitution to FO...
I have almost all parts, and started populating PCB
 

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J

J.M.K

Member
Joined 2009
After quite some hours listening,
it doesn't sound so different ............ just very very very good
and lots of pleasure.


Ok, now I'm back to the FO, as I still have quite some work to do on this
V4H enclosure.
I must say I've lost something, like I wrote in my previous comment.
FO is very good and smooth, but quite less punch and less overall balance (both have a huge headroom).

JM:) (sorry, pictures not very good)
 

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