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EAR 834P - Tube Rolling

Discussion in 'audio' started by rough edges, Sep 27, 2019.

  1. rough edges

    rough edges pfm Member

    I got one of these this week, and I've suddenly discovered that I like valves. A lot.
    This is a new unit, so it needs to run in a bit, but I have read quite a bit on the topic of tube rolling and I was wondering if any fishies have fave tube combos for the 834P.
    The thing sounds excellent with the supplied tubes, and I'm not in any hurry here, but it would be nice to have some ideas when the time comes.

    Thanks
     
  2. Tony L

    Tony L Administrator

    A lot depends on the cartridge and system, and you’ll find a world of options over on AudioAsylum where this is a very popular phono stage. When I had one I ended up with a GE 5751 in the input stage (to drop the gain a bit), a really nice ECC83 in the middle position (I liked several), which is the RIAA curve IIRC, and a black plate RCA 5814A as the cathode follower (which is actually an ECC82 type valve). For me in my system that sounded far bigger and more dynamic than the stock valve set.
     
  3. rough edges

    rough edges pfm Member

    Did you find that the differences between tubes was substantial, or more of a subtle thing? This is all new to me...
     
  4. Tony L

    Tony L Administrator

    Pretty substantial and the 834P responds well. I’d not be in a huge rush though if you’ve just got it, certainly enjoy it for a while as-is, but work on the assumption there is real potential for tuning it to taste at a later stage.
     
  5. rough edges

    rough edges pfm Member

    I’m using a Nag MP500 into the EAR, and the sound is so different from the Graham Slee I was using, it’s beyond belief for me. I didn’t expect this at all. You know how much hyperbole there is out there.
    I think that your advice to not be in a rush is wise. I really enjoy it stock. It is good to know, though, that there’s nice potential for tuning when that inevitable day comes. It sure is a nice piece of kit.
     
  6. Mike P

    Mike P pfm Member

    After some tube rolling in mine I've ended up with some nice old Mullard ECC83's (161 code) in the first two positions and a new old stock (actually brand new not just old!) Mazda ECC82 in the final position.

    Swapping to a good ECC82 in the final position was a big change (for the better).
     
  7. rough edges

    rough edges pfm Member

    I've read about using an ECC82 in V3; are the Mullards warm and lush?
     
  8. G T Audio

    G T Audio Trade: Manufacturer and Distributor

    Normally the 834P comes with 3 x 12AX7's (ECC83), so if you do change out the cathode follower to a 12AU7 (ECC82) you should really rebias that valve to take advantage of its superior performance as a cathode follower.
     
    Arkless Electronics likes this.
  9. manicatel

    manicatel pfm Member

    I had an 834p years ago. It was my first bit of valve gear. Absolutely Loved it.
    I did roll some different valves in but can't remember what they were/what position they were. Luckily though, as has been said, there's loads of great info for the 834p on different sites. Only thing I'd say is that sometimes, tube rolling gives a "different" sound rather than an outright 'better" sound. But that's all part of the fun & ecc83's don't have to cost huge amounts to experiment with.
    Enjoy!
     
  10. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    Indeed yes! I mention this every time it is suggested people use the wrong valves in things...
     
    G T Audio likes this.
  11. rough edges

    rough edges pfm Member

    Not wanting to open a can of worms here, but is there a run in period for a valve phono stage, and what kind of timeframe are we looking at?
     
  12. Vinny

    Vinny pfm Member

    I have a Croft pre with stage and I have run countless valves through it - it is a very simple design and is influenced in how it sounds by what valves are used. I would say that by the time you have put something on to play and settled to listen, you will have very near the whole flavour of what you have installed.

    For me, tube rolling produces very subtle, but at the same time very significant, changes in sound. Differences are NOT black v white, it is all shades of grey that are best appreciated (or not), when sat back with a few tracks of what you really like and know well.

    Unfortunately, on the one hand, ECC83 (and ECC82) is a very, very, very common valve in amp's, so they command relatively high prices because of demand. On the other hand, they were a phenomenally common valve in every kind of electronic gear imaginable, when valves ruled, so there are stacks and stacks to choose from, even today.

    Prices are mahoosively influenced, so far as I can see, by what chatter says are "great", so old Telefunken and Mullard valves are lunatic prices, in the main. Anything with black plates similarly.

    Get used to what you have for a few weeks before dipping your toes would be my advice. Second bit of advice - get together a list of the (approx.) 467394549 different codes that are the same as, or VERY near to ECC83s, such as 12AX7, 5751, etc. etc. etc. etc..
     
  13. oceanobsession

    oceanobsession pfm Member

    The Philips ecg green print 5963 £8.00 on the bay nos , all the valves make a fairly big difference in this phono , mullards are pipe and slippers , but im told the box anode is better . phil.
     
    Vinny likes this.
  14. Vinny

    Vinny pfm Member

    Philips ECG = Sylvania USA.
    5963 are ECC82s designed for use in computers where they'd sit idle for 99% of the time - I have tried a few makes/brands and been uninspired, but...………… they are always cheap...…………………….

    Someone else who thinks Mullard are rather sleepy :) I thought that I was the only one.
     
    Last edited: Sep 29, 2019
  15. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    Oh no you're not... but it doesn't apply to all Mullard valves. I'm really liking EI nickel anode valves in my Leak St20. I'd had several part used ones I took from guitar amplifiers laying around but just thought they were some el cheapo eastern block rubbish and they couldn't even "use the right metal" for the anodes until TonyL recommended them in another thread and I though "nothing to lose in trying them..." Very good they are too!

    As I have said before though, the way valves are used ie the circuit topology, the anode voltage and current etc are MUCH more important at the end of the day than the brand!

    A very good choice for the cathode follower would be the ECC88 but it would need considerable reworking of the 834 to use them... different pin out, meaning re-wiring the valve base, for a start and then changes to resistor values etc.
     
  16. Vinny

    Vinny pfm Member

    LOL

    How many here would have the first clue about Ei though? Without resorting to Google, and then having a challenge finding anything?

    I'll stick by my brand = shade of grey/flavour, rather than being night v day. I very much like my Croft and the flavours that it can produce.

    I am REALLY intrigued by the ECC82 v ECC88 thing though. Why should an ECC88 produce "better" music? (This from a point of near total ignorance rather than belligerence.)
     
  17. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    Well I guess that whether or not it produces ""better" music" would be in the ear of the beholder but it would make a vastly better cathode follower in every technical sense. As both myself and GT said up thread though, even if using the ECC82 it really needs some changes to resistor values to bias it correctly, although it is of the same pin out. 83 works best at about 1mA but 82 more like 8-10mA so by just swapping one for the other you are hearing the ECC82 in a highly compromised situation...
     
    G T Audio likes this.
  18. Vinny

    Vinny pfm Member

    Granted, people seem to hack valves about with no logic or reason, though most especially with guitar amp's, but I was speaking in a more general sense, and in my own case, a Croft, which is designed for an ECC82 follower, so any change would be from ECC82 circuitry to ECC88.

    Is there any way to make a general comment about what the circuit would achieve ECC83 v ECC88, and make some leap of logic to what anyone should/might hear?
     
  19. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    I actually posted a long thread on it with figures etc just a week or two ago... sorry can't remember what the thread was...

    To summarise, the ECC88 would have lower output impedance and greater current "drive" than an ECC83 by around a factor of 10. The ECC83 makes a shite cathode follower but a good voltage amplifier.. horses for courses.

    Adding an active current sink to replace the cathode resistor would likely make a good improvement subjectively also.. reputedly... I almost always use the active version anyway, as it's just better, so I've never built two identical versions with one active and one passive to compare them.... but if you do some googling you'll probably find all sorts of comments about any cathode follower without an active current sink (or a negative high voltage rail to allow a very large cathode resistor... same effect...) being dodgy subjectively.... "sat on" dynamics is the most common complaint IIRC.
     
  20. oceanobsession

    oceanobsession pfm Member

    definitely ecc82
    eBay item number:
    390677291325
     

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