Tony L
Administrator
When I had one IIRC I ended up with a GE 5751 in P1, a Sovtek 12AX7LPS in P2, and a black-plate RCA 5814A (actually an ECC82 type) in P3. Definitely worth experimenting a fair bit and good NOS can pay off. P1 is the input gain, which is why I used a 5751 as I had a high output cart (2M Black), P2 is the RIAA curve, and this has to be a ECC83, P3 is the cathode-follower/output and I felt the 5814A drove my preamp far better.
There is a wealth of real geekery over on Audio Asylum about this phono stage. I learned a lot of things to try there.
There is a wealth of real geekery over on Audio Asylum about this phono stage. I learned a lot of things to try there.
Thanks for the input, very useful indeed! I can see there's a lot to learn about this phonostage.
rough edges
Sapere Aude
In my 834P, I use a 1964 Raytheon (Windmill) 5751 in V1, a Mazda Belvu 12ax7s in V2, and a 1953 RCA Blackplate 12ax7 in V3. The GE 5751 that Tony mentions above is also excellent in V1. Old Mullards are also very nice in this phono stage.
MikeMA
pfm Member
By coincidence, I was swapping valves around in my EAR 834P yesterday. I tried the combination recommended by @Tony L and thought it sounded dull, closed in and a bit lifeless. I ended up reinserting the Td'P stock valves - 12AX7s of some sort - and it came back to life. I will now leave it alone.
Ei valves are WAY more likely to be available under one of the stockholder brands - CVC, Zaerix, Bently, Pinnacle, Orion, Thermionic, etc., than they are under their own brand. Loads of valves branded Philips were also made by Ei.
I don't know if all Ei valves were ID'd as per Philips system, but they were all but a Philips subsidiary for the vast bulk of their life and 1958 CVC branded ECC83s here have the silver ink ID of Philips, showing manufacture by Ei (a broad upside-down U with a dot in the middle).
Mazda Belvu would near certainly have been made when Mazda was licensed to Thorn EMI, so would also very likely appear as Brimar - the main Thorn EMI valve brand. (Brimar was originally an STC? brand, if memory serves.)
Quite a few of the valves mentioned so far are usually eye-wateringly expensive now, so be warned.
I don't know if all Ei valves were ID'd as per Philips system, but they were all but a Philips subsidiary for the vast bulk of their life and 1958 CVC branded ECC83s here have the silver ink ID of Philips, showing manufacture by Ei (a broad upside-down U with a dot in the middle).
Mazda Belvu would near certainly have been made when Mazda was licensed to Thorn EMI, so would also very likely appear as Brimar - the main Thorn EMI valve brand. (Brimar was originally an STC? brand, if memory serves.)
Quite a few of the valves mentioned so far are usually eye-wateringly expensive now, so be warned.
Mike P
Trade: Pickwell Audio
I tried an ecc82 in the V3 position (complete with adjusted cathode bias resistor value) but ended up going back to a trio of ecc83's and the original resistor value.
In my case dialling in the cartridge loading resistance and capacitance made by far the biggest improvement.
I also prefer the sound now that I have polystyrenes in the RIAA section instead of silvered mica.
In my case dialling in the cartridge loading resistance and capacitance made by far the biggest improvement.
I also prefer the sound now that I have polystyrenes in the RIAA section instead of silvered mica.
Tony L
Administrator
Do bare in mind I was deliberately trying to drop gain a bit with the 5751 (the 834P was way louder than my CD player with the 2M!), that change may well not suit a different cart.
Regardless I’d certainly have a listen to any options you have available. IIRC the stock TdP valves are current production JJs. These are really not hard to better if you are prepared to look at NOS.
MikeMA
pfm Member
Yes, I should have qualified my comments along the lines of "my ears, my kit and my room"! Having said that, I've never experienced the apparently dramatic differences with small signal tubes which others hear. I think TdP has used different brands in his kit over the years, and I'm pretty sure that my 834P came with Sovtek 12AX7LPS tubes. I've always regarded Sovteks as pretty decent sensibly priced current production tubes. Hunting out decent NOS stuff has become a bit of a nightmare and, for me at least, simply not worth the cost and risk.
Tony L
Administrator
The Sovtek 12AX7LPS are a very good valve by any standard IMO. The only new production small signal valve I’ve found that I like. It can’t match a good vintage Mullard for top end detail, soundstage, that ‘real’ thing they do etc, but they are great in the bass (deep, tight, controlled) and don’t really do anything wrong elsewhere IMO. They just lack the depth and realism of the very best. By saying that as ever context is everything. I found the Sovteks unbeatable in the ECC83 position of my old Prima Luna Prologue Two, they saw everything off, though I definitely prefer 50s or early-60s Mullards in my Leaks and Verdier pre. As ever always worth playing about a bit. They do all sound different IME.
I wasn't aware you could alter any settings, I assumed it was just MM or MC. I'm new to this so learning as I go. At the moment I've got it switched to MM, as I'm using a Soundsmith MI cartridge which I believe is similar to a high output MC.
I'm going to have to pop the lid off and have a look at what's in there.
Arkless Electronics
Trade: Amp design and repairs.
I fully agree with TdP!! Do not use valves of the wrong type in anything ever. Circuitry is designed around the characteristics of a particular valve. The value of the resistors etc are chosen to set voltages and currents to the correct values to give optimum results with that valve type in that circuit. The 12AT7, 12AU7 and 12AX7 (ECC81, ECC82 and ECC83) have the same pin out and so will function when one type is changed for another, but functioning can be way different to working correctly and as the designer intended.
MikeMA
pfm Member
You are right, there aren't any user adjustable settings as such, just the MM/MC switch. Anything else would mean a soldering iron and swapping out resistors and capacitors etc. You'd have to know what you were doing, thus excluding people like me!
I am firmly in the same category! I think I'll stick to a bit of gentle tube rolling where it's unlikey I'll break anything
Arkless Electronics
Trade: Amp design and repairs.
FWIW the EAR 834P and Croft (which one!!?
) are very similar indeed.
) are very similar indeed.FWIW the EAR 834P and Croft (which one!!?
LOL - indeed, which version.......
Usually 2 x ECC83 in a Croft MM phono, what are the equivalents in the EAR? P1 and P2?
MikeMA
pfm Member
The same.
Arkless Electronics
Trade: Amp design and repairs.
2 x ECC83! Both use shunt feedback RIAA networks around a gain stage consisting of a single triode. The main difference is that the EAR has the cathode follower added as a permanent part of the phono stage and takes the feedback from after the follower whereas the Croft takes the feedback from before the cathode follower, allowing the cathode follower to be used as the line stage in MM pre amp versions. In versions of the Croft where it is only a phono stage then the cathode follower is missing and the output is what would be the Tape Out in the full pre amp version. EAR 834P then has considerably better driving ability and lower output impedance than a Croft phono stage.
If you took a Croft full pre amp and removed the vol control and input selector so it goes straight into the cathode follower and then took the feed to the RIAA network from the cathode follower rather than the second valve you have the EAR 834P.