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Concordant Excelsior - who knows about history of this pre?

Arkless Electronics said:
I just googled that model and it shows pics of a pre with 6 valves! Hmmm...
Odd that it uses 2 5965's if they are used as followers as it's a dual triode and one could do both channels....

Anyway unless a schematic turns up the original circuitry will be a matter of speculation...

Negative feedback sets the gain and so it can be whatever you like. With one ECC83 half per channel the max would be about x 80-90 or so and that would be with no feedback.

With a ECC83 per channel anything up to about x 8000 possible with no feedback. Of course in practice feedback would be used (not much choice with the very high gain of the ECC83!) and with all that gain available distortion down at less than 0.01% easily possible.... maybe 0.003% or so.

With some difficulty it is possible to use 3 triodes per channel in the "ring of three" configuration as a DC amplifier with no capacitors at all.... A version with just one cap (output cap) rather easier...
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Yes, sorry, there's also 2x6CG7 used, I think, as power supply rectification. I have been trying to get a schematic for the Exhilarant for ages but to no avail.

So in theory then, the amp could be modded to use two halves of the '83 and 5965 which could allow for a reduction in gain without negatively affecting performance...?
 
eastone said:
Yes, sorry, there's also 2x6CG7 used, I think, as power supply rectification. I have been trying to get a schematic for the Exhilarant for ages but to no avail.

So in theory then, the amp could be modded to use two halves of the '83 and 5965 which could allow for a reduction in gain without negatively affecting performance...?
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Hmm... 6CG7 is a double triode, not a rectifier.

In theory, if you were wanting to use it as a casework complete with PSU and valve sockets, vol control and phono sockets etc then the worlds your lobster... it could be made into all sorts of permutations.

If reducing gain is your primary concern then the original could easily be modded to reduce the gain.

6CG7 is a fairly low gain triode and could be used in a zero feedback pre.... probably with more gain than you want though...
 
He probably meant "regulation" not "rectification"...

It had triode pass elements in a voltage regulator.
 
Yank said:
He probably meant "regulation" not "rectification"...

It had triode pass elements in a voltage regulator.
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Quite possible... as I said earlier everything is speculation without a schematic... or having one to reverse engineer to make a schematic...
 
Hmm it’s a 6CG7 mystery. I was under the impression the amp had no regulation...?

I have no great desire to rip the amp apart. I like it a lot. I suppose I just thought: lower gain; fewer valves £££ wise (= tastier NOS varieties); and possibly lower feedback... could be interesting??
 
Ian,

When was the last time you saw another Concordat Exhilarant?

Or even another that's pretty much mint?

Please don't butcher it! If you fancy a change then buy something else.
 
eastone said:
Hmm it’s a 6CG7 mystery. I was under the impression the amp had no regulation...?

I have no great desire to rip the amp apart. I like it a lot. I suppose I just thought: lower gain; fewer valves £££ wise (= tastier NOS varieties); and possibly lower feedback... could be interesting??
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I'm afraid that modifying it into a different amplifier whilst simultaneously leaving it standard is beyond even my abilities :confused::rolleyes:
 
Dan K said:
Ian,

When was the last time you saw another Concordat Exhilarant?

Or even another that's pretty much mint?

Please don't butcher it! If you fancy a change then buy something else.
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Just shooting the breeze Dan. I certainly wouldn’t want to do anything irreversible to it.

I’m not looking for a change just for the sake of it. The only things that irk me about are the price of the best NOS ‘83s and the fact I have a little too much gain.

I think it’d be fascinating to clone / play with this circuit. Probably relatively inexpensive given the low parts count.
 
eastone said:
Just shooting the breeze Dan. I certainly wouldn’t want to do anything irreversible to it.

I’m not looking for a change. The only things that irk me about are the price of the best NOS ‘83s and the fact I have a little too much gain.

I think it’d be fascinating to clone / play with this circuit. Probably relatively inexpensive given the low parts count.
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There's a simple single valve line pre in DIY section which I designed if you are looking for a DIY project;)
 
Arkless Electronics said:
I just googled that model and it shows pics of a pre with 6 valves! Hmmm...
Odd that it uses 2 5965's if they are used as followers as it's a dual triode and one could do both channels....
Click to expand...

If they are not power supply components, then I can think of two possible explanations for two dual triodes - followers for both phono and line, or totem-pole followers.
 
Yank said:
If they are not power supply components, then I can think of two possible explanations for two dual triodes - followers for both phono and line, or totem-pole followers.
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It is a line-only unit. I suspect I got it wrong above and they are doing the regulation.
 
Yes. A quick Google should confirm that. 1.5uF, sometimes they are doubled up, sometimes not.

Come on Jez, we want your opinion on the circuit.

Looks like one cathode follower after another, with a feedback loop back to the second triode, which appears to have almost no bias. I have wondered if Tankertop wasn't playing a joke and rewired it like this just for the photo.

Is this the 'ring of 3' that you mentioned? Any details on that?
 
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Given the paucity of components on the topside of the board, I was expecting there to be more underneath than just jumper wires.
 
Dan K said:
https://www.flickr.com/photos/31961294@N07/8979514104/

Should give you something to ponder :)
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Yank said:
Given the paucity of components on the topside of the board, I was expecting there to be more underneath than just jumper wires.
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Looking at the photos, and my early Concordant, the transformer is obviously missing, and it looks as if the heaters might be AC. Mine, and the Excelsior diagram I have show DC heaters, with the PSU in a separate case.
There aren't that many components in his preamps, if you exclude the PSU.
 
Yep AC heaters, one pair appears to be balanced and the others not, this amp has almost nothing to do with the Excelsior

Come on Jez, an Engineer of your talents could tell what was going on in seconds. The input is on the far left in the pics and the output is at the opposite end of the yellow caps. The odd part is the small red wire between the 2nd and 3rd triode.

Maybe another pfmer can shed some light on this
 
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