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PeeCeeBee V4H GB

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G

giaspyr

Member
Joined 2011
J.M.K said:
I'm still into it.
The best Hfe match I got are some BC556B around 348 and
almost all BC546B around 414.
Is it going to actually make any audible issue ?
Anybody knowing a reliable source for something better ?

JM
Click to expand...
I bought 50pcs of each transistor from acdcshop.gr - ?????????? ??? ??????????? ????????? online
Transistor PNP, bipolar, 65V, 100mA, 500mW, TO92 - 0.03 EUR : acdcshop.gr - Online shopping
Transistor NPN, bipolar, 65V, 100mA, 500mW, TO92 - 0.03 EUR : acdcshop.gr - Buy online in this price
some of them were very closed matched with a difference of about 8-10 Hfe and they are very cheap, as I see they ship to EU with a cost of about 8-9euro.

How many do you need? maybe I can pick some matched from the ones I've got left and post them to you if you just cover the shipping cost to France.
 
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G

giaspyr

Member
Joined 2011
shaan said:
Hi.

The v4h does have its own sound but dull/muddy it is not. So definitely something is going wrong. Turn on the amp and slightly touch the 10ohm resistors near the output and check if they are warm. If not, then the problem may be coming from a faulty transistor or capacitor that is running off its specification. Have you checked VAS bias at the 47ohm resistors? What transistors are you using at VAS?
Click to expand...
Hi Shaan and sorry for my late reply, problem is solved, somehow VAS bias was drifted down or misadjusted?? to 70.0mVs, after readjusting VAS bias amp sounds as it should!

VAS transistors used are MJE340/MJE350.

Thanks a lot for the help.
 
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G

giaspyr

Member
Joined 2011
Finally, here some pics of the amp
IMG-20201207-110803.jpg

IMG-20201207-110832.jpg

IMG-20201207-110739.jpg
IMG-20201030-110630.jpg
 
shaan

shaan

Member
Joined 2009
meanman1964 said:
I own the first 4H boards , which can be updated to Rev 1 but is it possible to updated to Rev 2 ?
Click to expand...

Yes.

1. Cut the two ground tracks in front of Q5 and Q6 on the bottom layer. Install one 4K7 1/4 watt resistor across each of these cuts.

2. Install the 1N4148 diodes at mosfet gates (pin 1) - anodes to gates for Q11/Q13 and cathodes to gates for Q12/Q14. Install the 10V diodes to mosfet sources (pin 2) - anodes to sources for Q11/Q13 and cathodes to sources for Q12/Q14. Join the open leads of the diodes together for each pair on each mosfet.

Done.
 
shaan

shaan

Member
Joined 2009
giaspyr said:
Hi Shaan and sorry for my late reply, problem is solved, somehow VAS bias was drifted down or misadjusted?? to 70.0mVs, after readjusting VAS bias amp sounds as it should!

VAS transistors used are MJE340/MJE350.

Thanks a lot for the help.
Click to expand...

giaspyr said:
Finally, here some pics of the amp
Click to expand...

Great news! :up::)

Congrats, and what a nice cab with both wood and meters!!!!!

:worship: :cheers:
 
G

giaspyr

Member
Joined 2011
Yes Shaan is right, the VU meters panel is taken from an old Uher reference 1 150W power amp which used STKs at the output stage and had awful sound, I copied the VU driver stage to a protoboard and the VU meters are driven exactly as they originally were, the meters driver is fed directly from the amp's output.
 
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T

tcpip

Member
Joined 2003
tcpip.dhandanought.org/
giaspyr said:
Yes Shaan is right, the VU meters panel is taken from an old Uher reference 1 150W power amp which used STKs at the output stage and had awful sound, I copied the VU driver stage to a protoboard and the VU meters are driven exactly as they originally were, the meters driver is fed directly from the amp's output.
Click to expand...
Wow, so you're not feeding line level signals to the driver? Does this mean the driver board doesn't need any on-board amplification and a passive bridge rectifier is enough?
 
K

Kana711104

Member
Joined 2018
2 PCB

shaan said:
GB UPDATE:

Torvbakkane - 6 PCBs - SHIPPED
Faizal Mansar Alam - 2 MODULES - SHIPPED
J.M.K - 4 PCBs - SHIPPED
prairieboy - 2 PCBs - SHIPPED
nrabbit - 2 PCBs + MOSFETS - SHIPPED
deps - 2 PCBs - SHIPPED
Greg1017 - 2 PCBs + MOSFETS - SHIPPED
CitizenKane - 4 PCBs - SHIPPED
surajspai - 2 PCBs - SHIPPED
Rick G - 4 PCBs - SHIPPING WITH PREAMP
blek stena - 2 PCBs - SHIPPING WITH PREAMP
routhun - 2 PCBs - SHIPPING WITH PREAMP
Pistollero - 2 PCBs + MOSFETS - DELAYED DUE TO TEMPORARY SUSPENSION OF SERVICE. WILL BE CONTACTED VIA PM/email.
RobSoet - 4 PCBs + MOSFETS - SHIPPING INVOICE SENT

I still have a few PCBs. If anyone needs a pair let me know.
Click to expand...
Kana711104 2 PCB:nod:
 
shaan

shaan

Member
Joined 2009
LAST GB UPDATE:

Torvbakkane - 6 PCBs - SHIPPED
Faizal Mansar Alam - 2 MODULES - SHIPPED
J.M.K - 4 PCBs - SHIPPED
prairieboy - 2 PCBs - SHIPPED
nrabbit - 2 PCBs + MOSFETS - SHIPPED
deps - 2 PCBs - SHIPPED
Greg1017 - 2 PCBs + MOSFETS - SHIPPED
CitizenKane - 4 PCBs - SHIPPED
surajspai - 2 PCBs - SHIPPED
Rick G - 4 PCBs - SHIPPED
blek stena - 2 PCBs - SHIPPED
routhun - 2 PCBs - SHIPPED
Pistollero - 2 PCBs + MOSFETS - SHIPPED
RobSoet - 4 PCBs + MOSFETS - SHIPPED

Moving on to next GB.
 
shaan

shaan

Member
Joined 2009
JAN 2021 GB UPDATE

mahtew - 2 V4H + MOSFETS - POLAND - FULL PAID
Kana711104 - 2 PCB - INDIA - INVOICE SENT
telekineze - 2 PCB + MOSFETS - LITHUANIA - FULL PAID (SHIPPING WITH PREAMP AND PSU)
robodo - 2 PCB - CZECH REP. - FULL PAID

Boards are already home. Shipping starts from Monday next week.
 
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