Lite Audio Phono Stage

[Dave the bass]

Hello,

I'm a newcomer to the world of Valve Hi Fi but after gigging for years with Valve amps (I'm a Semi-pro Bassist) have finally started 'playing with' and building a Valve Pre-amp stage.

This is the first project I've built myself although I've been an Electronic Technician for over 20 years since School/College. Seems like I've missed out on a lot I was only taught Solid state theory during my C+G 224 so I've a lot of catching up to do.

Anyway, as an 'easy break in' and first attempt I bought a kit off eBay comprising of a 'Lite Audio' LS37 MM/MC Phono Pre amp and the Valve regulated PSU to go with it.

I gingerly powered it up today and guess what....it works! I need to find some nice boxes as I want to house the PSU and Pre-amp separatley to cut down on hum and noise, it seems very microphonic.

It sounds great to me, I was wondering if any of you wise Sages had any experiences of this kit?

Thanks in advance,

Dave the bass.

[NickG]

Thats a new one on me, got any more details, circuit diag. Nothing more interesting than a new phono stage :-)

Note the phono shootout thats coming soon, may be of interest to you?

[Global]

Hi Dave

Not a 'wise sage' but I do have the kit which I have not yet built! I have had it for some time and did look into some optional tweaks.

There is a good set of notes on converting the rectifier to 6X4 which is a good idea 'cos you'll never find a spare Chinese 6Z4! Also you can improve the regulation of the unit and get a nice glowing gas regulator fitted too.

Have a look here

http://eshop.diyclub.biz/article_info.php?articles_id=3

In theory this should make a considerable difference!

Cheers

Mark

[Dave the bass]

http://www.tommytube.com/dunkin/LS37.pdf


I found this (huge copy) of the cct diagram on an American (I think) thread.

I know very little about it other than

a) It fitted my teeny weeny budget!
b) Its VALVE!
c) Its the first stage (literally) of my bid to build up an all-valve Hi Fi in stages.
d) Did I mention its easy to put together too?

That was a quick reply too Nick, was you laying in wait!!??

All the best

Dave the bass.

[Dave the bass]

Originally Posted by Global

Also you can improve the regulation of the unit and get a nice glowing gas regulator fitted too.

Cheers

Mark

Blimey!

Looks like I need to connect it to the CH boiler to then eh?! 'Glowing Gas regulator...oh er Missus.

Thanks very much for that link Mark,

You guys are hot off the line arn't you, I only posted a few mins ago Glad someones heard of it.

Dave the bass.

[Shane]

Funny, that. Central heating boilers are a hot topic round here at the moment...

[NickG]

Interesting circuit, the MC grounded grid input is one for Ian to try. Does anyone have a circuit for the power supply.

DTB, you will discover phono stages are an obsessive subject for at least a couple of the folk around here :-)

[Dave the bass]

Originally Posted by NickG

Interesting circuit, the MC grounded grid input is one for Ian to try. Does anyone have a circuit for the power supply.

DTB, you will discover phono stages are an obsessive subject for at least a couple of the folk around here :-)

My work colleagues think I'm obsessive about sound/music anyway so thats fine with me

Re- Grounded Grid, what does that function as? I've looked at various cct diagrams of Valve equipment in that past but haven't seen that before.

As far as I can make out its only used on the MC inputs, the dip switches switch in and out resistors in parallel to match the cartridge windings I guess (I'm new to all this so feel free to 'point and laff' if I'm wrong!!! I know no shame!)

I'm using an old 1981 (?) Pioneer PL100X Belt Drive TT with a Shure M75ED Mk2 Cartridge which I believe is MM. So I only need to switch in the 47K ohm resistor which is the correct loading for a MM cartridge I read (Thanks to Hi Fi world last month, 1st time I've bought a Hi Fi mag since 1983 when I was at college, I've now subscribed).

I don't have a scanner at the moment but I'll try and find a copy of the PSU and post it here ASAP.

Thanks for all the encouragement, nice welcome BTW.

DTB

[Dave the bass]

Originally Posted by Shane

Funny, that. Central heating boilers are a hot topic round here at the moment...

Hot topic, Central heating...arf. I geddit

DTB

[James D]

Grounded grid configuration gives you low input impedance and high output impedance and functions as a voltage amplifier only so voltage gain but no power or current gain. OK for an mc input but not real smart.. except its noise performance is a little better - not enough to be significant though...

James