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-   -   Against all odds... (http://www.diyaudio.com/forums/tubes-valves/40398-against-all-odds.html)

dhaen 3rd September 2004 12:28 PM

Against all odds...
 
If someone were to propose a design that used:
Parallel Single Ended
Distributed load pentode connected EL34's
ECC82's:
One as cathode follower,
fed by 2 * voltage amplifier stages
Low speed SS rectifiers
Mixed AC & DC heaters

Almost everyone (me included) would critisise one or more elements.

What I'm describing is a "Union Research Simply Four'.
I repaired it yesterday and have been listening since. It's got deep bass and sweet mids and highs with nice imaging. It sounds perfectly balanced to me. Mind you, it has a big bank of iron under the cover, and as many have said in the past, it's the iron that makes the most difference.

I'm pleasantly surprised :)

NickC 3rd September 2004 06:09 PM

Dhaen
I have repaired the unison research simply 845 and i find it rather blend sounding thin and unevovling. Rather a waste of money on audio but superb on the furniture/decor
I heard the simply four but did not really shout much about it. I guess results will vary.

Sch3mat1c 3rd September 2004 10:21 PM

Re: Against all odds...
 
Quote:

Originally posted by dhaen
If someone were to propose a design that used:
Parallel Single Ended
Distributed load pentode connected EL34's
ECC82's:
One as cathode follower,
fed by 2 * voltage amplifier stages
Low speed SS rectifiers
Mixed AC & DC heaters

Almost everyone (me included) would critisise one or more elements.

Heheheh. I think I should rewire Hept'AU7 with steel wires instead of copper. Oh, and replace the 6SN7 and interstage transformer with another pair of 12AU7s or something. Then come back here and tell all how the upgrade sounds better.

:D

Tim

fdegrove 3rd September 2004 11:39 PM

Hi,

Quote:

I repaired it yesterday and have been listening since.
John, if you don't mind measuring the voltages on the ECC82s you may be in for a surprise...
If I'm not mistaken they use that valve with unusually low plate voltages.

I heard these amps too, many a moon ago and while it wasn't my cupper it did seem to get the knods from quite a few others present.

Cheers, ;)

v-man 4th September 2004 12:39 AM

sometimes even the most undesireable piece of equipment, when put within a paticular system can yeild suprising results.
;)

dhaen 4th September 2004 10:29 PM

Frank,

Anode of voltage amplifier: 154v
Anode of subsequent cathode follower: 309v
Didn't record the voltage on anode of first voltage amp.

Is this what you expected?


All,

This amplfier was only remarkable in respect that according to "forum advice" they'd done everything wrong. It was a good performer, and considerably better than expected. It was not outstanding.

fdegrove 5th September 2004 12:54 AM

Hi,

John,

Quote:

Is this what you expected?
Not exactly, IIRC it's the voltage amp that's really running from an unusually low anode voltage.
Thanks for taking the time anyway.


Cheers,;)


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