Re: Which tube expert can do custom works?





"Tynan AgviÐr" wrote:

Have you looked here ?
http://www.manleylabs.com/containerpages/16_299.html

They seem to be hybrid IC / tube designs though.

Graham



Yes, Sir. I dont want a hybrid design. I do not care particularly for the
sound of the manley products anyway. It has a sound which is sort of
bright, edgy, thin ? Not big, round and euphonic..(at least for their
microphone and the stingray,snappers and manley slam. )
Do you still design, Mr. Graham, do you have a website or? Who designed the
VACRAC products?

thank you Sir.

There isn't much terribly wrong with hybrids PROVIDING the SS device
isn't in the signal path, and unfortunately, many designers festoon tube
circuits
with umpteen SS mosfet buffers which mostly don't need to be there.
Often the buffer is there to better drive the NFB network providing a
large amount of loop NFB.
The NFB is there to get THD below a measured 0.01% and maximum output
which may never be used,
and may not be needed, or if used, maybe a fraction of the usual amount
of 20dB+ used
in many commercially made preamps.
The high level of NFB can make the tube amp indistinguishable from a not
so hot sounding SS design.

But constant current sources and sinks are a very good way to get rid of
dc carrying resistors
for tube current supplies and the anode output has to swing voltage and
current across the dc supply R
so the load on the tube isn't as high an ohmic value which could give
least THD and best sound.
The CCS allows the dc load R to dissappear from the loading, and the
triode
then acts like the near perfect voltage gain device because current
change is much minimized.

So when ppl say hybrid, unless you have a schematic and you can peruse
WHERE the
little bjts and mosfets and j-fets are actually used, then you can't
know if the circuit
is simple & good, or some silly wankers idea to use 4 times the number
of devices necessary.

ARC and CJ and Manley routinely have too much complexity on their
boards.

Patrick Turner.
.