Suggestions for phono stage please

[Max N]

I'd like a good phonostage.
Budget is a bit flexible, but to give an idea, years ago I auditioned a Musical Fidelity XLP and a Tom Evans microgroove. I liked the microgroove and would probably be happy with something at that level of performance but with more features.
I have some good MM cartridges so would ideally like to be able to switch between a MC input and a MM input.
I would also like to have gain adjustment and load resistance (and ideally even capacitive load adjustment) on the front panel. Failing that, easily accessible DIP switches would be OK.
Of course, sound quality is the most important thing, but I would like the above features if possible.
I would probably prefer to DIY, but am happy to go with a commercial product as well.
Any suggestions gratefully received
Max

[Mike H]

If DIY, I would say start with something simple that works. Certainly there's lots of designs about, problem is choosing one of them

Little Eddy is working on one now which simulates well.

Personally I got good results with the split EQ networks idea a la Bob Danielak, but his original cct is quite low on gain.

[Andrew]

Hi Max,

Unless you want an LCR, I would build a cascode front end using a jfet followed by a decent spec'd (e.g very well matched) RIAA with switchable 50kHz then choose a nice driver valve, perhaps with a buffer on the end depending upon the load the preamp is offering. and length of the cables.

I you want to be brave go balanced as, I understand it, the rest of your system already is, so why not go balanced right from the tonearm.

Andrew

[Nick]

That remids me, I said I would look up the Thorston LCR circuit for James. Woops, sorry James. Andrew know of a link to that circuit anywhere?

[Andrew]

Can do better than that, Nick

[Max N]

If DIY, I would say start with something simple that works. Certainly there's lots of designs about, problem is choosing one of them

Little Eddy is working on one now which simulates well.

Personally I got good results with the split EQ networks idea a la Bob Danielak, but his original cct is quite low on gain.

Mike, I agree, I am definitely looking for a proven design if I DIY. I'll google Bob Danielak, thanks

[Andrew]

I you want RIAA in a single shot then there's always Thorsten simple phono and my mods to it, I still use mine on a regular basis, not as good as the LCR, but a good pace to start.

Andrew

[Max N]

Hi Max,

Unless you want an LCR, I would build a cascode front end using a jfet followed by a decent spec'd (e.g very well matched) RIAA with switchable 50kHz then choose a nice driver valve, perhaps with a buffer on the end depending upon the load the preamp is offering. and length of the cables.

I you want to be brave go balanced as, I understand it, the rest of your system already is, so why not go balanced right from the tonearm.

Andrew

I did buy all the bits for Thorsten's LCR phono (including all the chokes). The only bit I didn't buy was the 600 ohm LCR modules themselves. I think S&B stopped making them? Although I notice they are available again now, along with some from Silk.
I guess I would also need some SUTs - just looked and the S&B 103 are £900 a pair now! Wish I'd bought some when they were cheap!
By the time I've bought the LCR modules and the SUTs and put everything in a nice box, I could have bought a nice second hand phono stage. I know that's not the point, and actually I would like another DIY project to get my teeth into.
Yep, balanced does appeal but I would prefer to work from a proven design. I just think that designing something from scratch will take me a long time. It would be fun, but actually I just want to be able to listen to vinyl again


Hmm, maybe look for a cheap secondhand microgroove to get me up and running, then DIY something as a longer term project.

[Max N]

Andrew, having thought a bit more, I am now leaning towards the LCR phono. Its a proven design and I have heard it and I know I like the way it sounds.

[Andrew]

I have a design for a higher/easier load than a 600R and Dave Slagle will wind you the chokes, mines 1k5, the only downside is you have to pot them/shield them yourself; my design is essentially a refinement of the Toccata mk2 but you could drop the 1k5 into the mk2 with no changes, you just get more gain. In reality, neither Nick nor I liked the zero bias design of Thorstens mk2, I ended up using diodes on both stages, same as the S. Bench designs did.

I think Sowter will wind chokes too and I think Llundhal have the standard 600R chokes in their inventory, so plenty of options.

If your feeling mad, I have a design for a balanced LCR on the drawing board

Andrew

[Andrew]

There was a chap on e-bay selling Partridge or ex-BBC microphone step ups for around £30 a pair a couple of years ago, he cottoned onto what he had and put his prices up; I struggled to tell the difference between them and the S&B, so second hand mic steps ups are a very cost effective option.

I'll see if he's still selling.


EDIT: yes he is....

http://www.ebay.co.uk/itm/PARTRIDGE-MOV ... 53e9fee83e

http://www.ebay.co.uk/itm/PARTRIDGE-MOV ... 53e9ef428b

If you get a higher load LCR then you get more gain so you may be OK with the 1:6.

Andrew

[shane]

Blimey. I paid £14 for mine..

[Andrew]

Blimey. I paid £14 for mine..

Yes, I think he found out how good they were, besides, I didn't want to tell Max that's what they were going for, in case it upset him. But in many ways they are still reasonable value compared to some of the commercial offerings and, as I said, last time I did a comparison I struggled to tell the difference.

Andrew

[Max N]

I have a design for a higher/easier load than a 600R and Dave Slagle will wind you the chokes, mines 1k5, the only downside is you have to pot them/shield them yourself; my design is essentially a refinement of the Toccata mk2 but you could drop the 1k5 into the mk2 with no changes, you just get more gain. In reality, neither Nick nor I liked the zero bias design of Thorstens mk2, I ended up using diodes on both stages, same as the S. Bench designs did.

I think Sowter will wind chokes too and I think Llundhal have the standard 600R chokes in their inventory, so plenty of options.

If your feeling mad, I have a design for a balanced LCR on the drawing board

Andrew

Yep, I remembered something about the zero bias being a bit dodgy - maybe grid current flowing through the secondary of the SUT? - in any case it seems unnecessary.
I've been out to the shed to check, and I have E810F and D3a - I was obviously quite serious about building one of these before S&B pulled the plug on the modules.

I always fancied a pair of Jensen SUTs, but have just read that there are some new Lundahls which seem to be getting good reviews.

Balanced LCR - oh man, just when I thought I had a plan coming together, you throw me that curve ball
OK, you've got my attention.

[Andrew]

Jim Hagerman's electronic step up is very good, called the Piccolo, I think, less organic than a step up, bass is a bit dry, but I enjoyed the loan of one for a couple of weeks.

If you can make it work, the right valve as a simple cathode coupled gain stage can sound very very good too, perhaps even better than a step up, shows what a step up gets wrong...but its hard to keep quiet enough, I think Nick might have succeeded. I need to have another go at that one.

A step up less MC stage is harder to do with an LCR as you throw all the gm away on driving the difficult load, or you get a choke the size of a house instead then its hard to get it linear. The design I alluded to above using a jfet and an RC RIAA would be "step up less", but a MC stage isn't possible with an LCR eq, sorry, not without a third gain stage.

Andrew