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lordmortlock

Can anyone tell me any more about this pre please?

12 posts in this topic

Home-made. Breadboard layout. Could be surprisingly good. Could equally be awful Jake. No indication about what the circuit is, and very difficult to tell.

Some good, some less so. Star grounded, looks like tube rectified HT, but then there looks like a solid state rectifier top right, if so, presumably for filaments. Construction has some nice touches, but is scruffy as hell.

A pure punt. Tubes don't look great. At £250 it could go either way.

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It does look home made. I've never heard of GTE. Maybe a two valve phono stage & two valve line stage. It also appears to have what might be a regulated power supply using an EL84? There's another darker valve next to that which could be a voltage reference or the error amplifying part of the regulator.

There does appear to be a conventional silicon bridge rectifier mounted on the chassis beyond those two valves but that might be doing filaments or HT. Can't tell. Indeed there may be another silicon bridge rec being fed by the red wires from the toroid. If so then that valve circuitry on the angle bracket may well be a regulator.

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Thanks Richard, good info. I should probably mention I bought it, just into an hours listening.

Its good. And not just for the money good. It certainly has my attention. You're right about the cooking lager ecc83s, but there's a nice mullard in the power supply (??), along with the larger valve that I can't identify.

Its a phono pre, so am I right in thinking two of the '83s will be the phono circuit?

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Thanks Guy - didn't spot your post as I was writing. I wonder if it's GTE or GATE, with the musical note as an A?

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No idea without a proper look.

At a guess, two ECC83 for line stage and two for phono. But that really is a guess. ECC83 and the like can accommodate two channels and there are as many possible circuits as there are designers. Tube rectumfryer for HT, possibly one tube as voltage reg (the odd one next to it) and a solid-state supply for heaters. All the RIAA stuff will be under the board, but will obviously be passive.

Just seen Guy's post. 100% agree, two red wires from the traffo to just to the right of that cap, but you can't see what's there.

Likely? As Guy suggests. Solid-state heater supply, tube-rectified HT with voltage reg, two small signal in the gain stage, two in the phono stage.

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Not the worst I've ever seen by a long stretch.

Assuming it's as it appears, it's a fairly conventional gain stage and phono, but nothing at all wrong with that. The casework is far better than average DIY, so I'd just enjoy it.

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Be interesting to know whether it uses active eq like the EAR 834P (or many US valve pre's) or it uses passive Eq but that'd require a much closer look.

I still think the two valves on the bracket will be a regulator circuit possibly referenced to a string of zeners? I also think it'll be SS rectified.

I guess the large valve could also be an ECL82 or 86 which incorporates a Pentode and a high gain triode stage. I have seen regulators built using those.

So few connections on that dark valve it may be a simple voltage reference like an 85A2.

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The dark valve is a mullard 90c1 Guy. That does a similar job doesn't it?

Yes, voltage reference tube.

http://www.r-type.org/exhib/aaa0876.htm

If have a few of these if you ever need a replacement.

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Thanks Guy - didn't spot your post as I was writing. I wonder if it's GTE or GATE, with the musical note as an A?

Hi,

There was a company called GATE that made valve amps. That is their symbol on that pre amp. They were around during the 90s.

SCIDB

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