Affordable but good MM phono stage.

pre65 · Post by **pre65** » Mon Dec 05, 2011 11:32 am

I did not want to "pollute" Max's other phono thread, so here is mine.

I'd like to attain better performance (and lower background noise) than my current WD Phono 3.

I looked up the price of LCR modules and they are a bit steep for me at the moment.

I found these modules on e-bay, are they likely to be "crap" in the opinion of our resident phono experts ?

http://www.ebay.co.uk/itm/Stereo-MM-Pho ... 8486wt_982

If so, are there any other options open to me up to about £100 ?

PS that £100 does not include what may be in the spares box. I do have some 6n2p valves (Ecc88 type ?) if that helps.

Post by **Nick** » Mon Dec 05, 2011 12:05 pm

Don't know what those modules are like, but I would have thought you would be hard pushed to better the Phono 3 using valves for £100.

pre65 · Post by **pre65** » Mon Dec 05, 2011 12:08 pm

Nick wrote:Don't know what those modules are like, but I would have thought you would be hard pushed to better the Phono 3 using valves for £100.

Perhaps I should try and find the cause of the background "hash" on the Phono 3 first then.

Post by **Nick** » Mon Dec 05, 2011 12:10 pm

I would, the phono 3 can be improved on, (IMHO) but its better than most out there.

Andrew · Post by **Andrew** » Mon Dec 05, 2011 12:56 pm

I would agree with Nick, its not a bad phono at all. You need to get it to someone who can do a spectrum analysis on it find out what' the noise is and then work out how to get rid of the noise. A spectrum analysis is not the only way but its probably the easiest.

Andrew

pre65 · Post by **pre65** » Mon Dec 05, 2011 1:02 pm

Good idea Andrew.

I will try a couple of low noise Ecc83 type valves first.

Who might have one of these here spectrum analysis thingies ?

Andrew · Post by **Andrew** » Mon Dec 05, 2011 1:11 pm

I have always wondered if the heater circuit was quiet enough on that design, but whether that is your hash, I do not know. Does it have a Low Drop Out regulator installed for the heaters? I know that was once a source of problems on the PHONO3 and Peter C was supposed to be sending out an update to kit owners.

Does it sound better if you don't use the PRE3 just power PHONO3 and use a different pre amp?

Then again, might just be something as simple as shielding and grounding.

Andrew

Andrew · Post by **Andrew** » Mon Dec 05, 2011 1:20 pm

I can measure it for you but you'd need to get it to me plus its power supply then I'd need to get it back to you. Shipping a few kilos around isn't cheap, I'm afraid, nor risk free. I could do it before the next meet and then bring it back when I come down so you only pay and have risk in one direction.

The other way is a decent sound card and something like Rightmark or Audiotester software and if you want to measure it with a signal you'd need to make up an inverse RIAA, preferably in a shielded box. The software needs a pretty hefty PC too. One tip if you go this route is that the capacitor coupled valve amps often have a DC voltage on the output at start up, don't plug the phono into the sound card until the DC has dropped way.

Andrew

pre65 · Post by **pre65** » Mon Dec 05, 2011 1:29 pm

I did have a problem when first built, and John Caswell fitted a LDO regulator which cured the original problem.

Pre3 is fine with all other sources.

I do have another valve pre with a phono stage. It's a Foundation Audio NP1, but I've never managed to find out who made it. It came secondhand from Ian Miller (the infamous Im2). I saw one on sale on e-bay a while ago from a dealer but he had no knowledge of them either.

The line stage uses two ECC88 (6n2p as of 5 mins ago

) and the phono stage is two ECC83 (but not a matched pair

) and a valve rectifier.

I'm going to try it in place of Pre3 later on to see what it sounds like with 6n2p.

Mike H · Post by **Mike H** » Mon Dec 05, 2011 1:47 pm

It might just be a ground problem?

Max N · Post by **Max N** » Wed Dec 07, 2011 10:03 pm

Has the noise always been there or has it deteriorated?

pre65 · Post by **pre65** » Wed Dec 07, 2011 10:30 pm

Max N wrote:Has the noise always been there or has it deteriorated?

I think it's always been there Max. I just never used to play vinyl very often.

If I wind the volume pot up so the hash is loud you can feel the 18" woofer vibrating. My other valve pre is not quite so noisy on phono but it's a similar sort of noise.

John Caswell told me it might be a combination of "shot" and "johnson" noise which is worse on high gain stages.

I'm bidding on some Ecc803s low noise valves as a first try at curing the problem.

Mike H · Post by **Mike H** » Thu Dec 08, 2011 5:17 pm

I dunno, not convinced. Need to try it with shorted phono plugs plugged in to the inputs to remove the input wiring, and see if it still does it. It may not

If it does, needs investigating. My current one was basically thrown together with no very special "techniques" to avoid noise & hum, other than "the usual", and it isn't noisy like that.

pre65 · Post by **pre65** » Fri Dec 09, 2011 9:40 am

Mike H wrote:I dunno, not convinced. Need to try it with shorted phono plugs plugged in to the inputs to remove the input wiring, and see if it still does it. It may not

If it does, needs investigating. My current one was basically thrown together with no very special "techniques" to avoid noise & hum, other than "the usual", and it isn't noisy like that.

I will try that later today.

Post by **Nick** » Fri Dec 09, 2011 12:23 pm

You say on the WD site that you have sensitive speakers, but I am not sure what difference that would make as you would just have the volume turned down. How does the level of the noise (as I assume it is white noise filtered via the RIAA we are talking about) compare to the background noise of a LP?

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