High ED: Here are my answers:
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From: ed koch
Sent: 23. dubna 1998 0:57
To: amps@contesting.com
Subject: [AMPS] qro 2500dx
thanks for reading this msg.
the qro 2500dx is an amp i`am considering purchasing in the near future. if
you own one, please take the time to respond to a few questions.
1. how is there customer service ? None
2. accrucy of the manual ? GOOD
3. quality of construction ? Worst you can imagine - pure
junk
4. overall design ? The author should go back to
the college and learn how diodes work
5. tune-up and operation ? Lousy
6. on the air reports ? Good
thanks for any info in advance.
73, ed n4ek
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The basic problem is that the construction of the powersupply and all the
control circuits is so bad.
1.The maximum screen voltage by SVETLANA is 350 V - compare to 500V in QRO
2. The maximum filament to cathode voltage is 100V, recommended close to 0
compare to some 140V in QRO
3.Control grid voltage in closed state is also too high.
4. Unbelievable mess in the G1 circuitry.
5.Stabilization of 24V is very overdriven since the maximum input voltage of
7824 used is also over shoot by well over 10V
all this results in :
The Screen current is unstable after few minutes of operation.
Before major rebuilt you can expect loss of the amp any minute.
Final comment:
I am unhappy owner of 2 pcs, which I bough on the recommendation of Tom N6BT. I
have already fixed each of the AMPs already more than 5 times !!!!
Finally I got mad and made major reconstruction and it seems to be OK now.
73 !
Jiri
OK1RI
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