Mullard 5-10 valve amp: Help

[admin_exported]

I have just got a Mullard 5-10 Valve Amp and I am having a small problem.

The pre-amp only has two coaxial inputs: one marked "G" and one marked "R". The selector switch is marked Radio "LP 78 MIC". Using adaptors I managed to get two RCA phono from my rega 2/ AT 110e cartridge into a coaxial input. The single speaker lead goes to an 8 Ohm Tannoy Mecury M2 speaker. With the "G" input selected and the pre-amp switched to "LP", I do hear the record except it is very quietly. All the valves light up. Am I missing something obvious like a different cartridge or speakers? Or is a trip to a valve amp in order? Or is there a book that someone could recommend regarding valve amp repair?

Any advice gratefully recieved.

 

[Anonymous]

I'm no expert but it sounds like you need a phono amp, this amplifies the low level signal from the turntable so it can be used in an amp without one inbuilt. Unless I'm missing something. This would explain the quiet sound.

Slightly confused, you mention coaxial inputs, these are digital not analogue interconnects!??

I apologise if this is an obvious oversight.

 

[Anonymous]

Many thanks Brisk.

I'll give it a go. The inputs are analogue coaxial - exactly the same as the aerial socket in the back of my TV! The amp was built in the 50s. I suspect the cartridges then had different outputs.

 

[Anonymous]

You may want to wait for another users comments to confirm this, I'm afraid my expertise are restricted to modern kit.

 

[Andrew Everard]

The inputs are probably for Gramophone and Radio, and will be mono, of course. Connecting it to a modern stereo cartridge is likely to be the problem, a) because it's stereo and b) because the output is too low. You'd need to run a vintage high output mono cartridge into this one...

 

[chebby]

The Mullard 5-10 equalisation circuits (for LP not 78s) were calibrated using Acos Hi G microgroove pickups and Collaro 'Studio' O & P pickups using a Decca LXT 2695 test disc.

Some network options are shown here in fig 3.

Some research (chapter 17 section 5i or page 11 in the pdf) tells me these were compliant to RIAA but - as Andrew states - were for mono and bear in mind the advice about tracking weights... "with a vertical force not exceeding 10grams" !

That should get you started

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