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Thread: Croft valve rolling question

  1. #1
    Join Date: Mar 2017

    Location: Melbourne

    Posts: 217
    I'm Karl.

    Default Croft valve rolling question

    Hi guys hope your all well.

    Im after a bit of advice from any Crofties or valve experts.

    Ive got the croft 25r with upgraded linestage
    And the 7r monos.

    After speaking with a few people the unanimous decision was that rolling the linestage 12bh7A will alter the sound the most and that the 50s NOS RCA valves seem to be most peoples go to choice for best of the best valve. It already has a nice nos Sylvania in there but i fancy a bit of fun to see if i can taylor the sound a bit more.

    Others also recommended that swapping out the line in valves on the monos has a nice effect. To get the clean detailed sound that i like i had been recommended the Nos GE 5751 in this position BUT luckily i took the top off to have a check as the valves in this position are also 12bh7A not ecc83 or variant types.

    Ive pulled the trigger on a nice(but expensive)pair of 1956 RCA black plates, NOS and matched and super strong. I will also pick up one more at next pay cheque to complete the trio that i need.

    Anyway enough rambling my question is, has anybody tried any different valves in the other positions?
    The rest of the valves in the pre are a Mullard 85A2 and 2 JJ ECC83S

    And one ECC83S and one 85A2 in the two mono.

    Will changing any of these effect the sound or are they just for power regulation? Its all new to me so not sure, and dont want to spend lots more on top NOS tubes if its not going to make a difference.

    Thanks for any help

    Karl


    Sent from my iPhone using Tapatalk
    Last edited by Bigbird; 18-05-2019 at 23:41.
    Linn Sondek LP12 ( Santos rosewood plinth ,Roksan Nima with Tiger Paw Skale and Yannis tonearm cable, Cirkus, Trampolin2, SSP12 inner platter, Tiger Paw tranquility, Vivid subchassis, Vinyl Passion thick top plate / Mose Hercules 2 gold power supply / Audio Technica ART 9 / Whest 2.2 phonostage / Croft 25RLS preamp with NOS RCA valves / Croft 7R monoblocks with NOS RCA valves/ Spendor SP2/3R2 / Chord cobra 3 interconnects / QED signature revelation speaker cable / Marantz CD DAC /Atacama Equinox rack

  2. #2
    Join Date: Apr 2012

    Location: London

    Posts: 583
    I'm James.

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    The 85A2 won't, it's a voltage stabilizer, the others might but the JJ are established favourites on the forums so you'd need to expect different rather than 'better' sound by rolling them.
    The obvious choices are box plate Mullard and pre JJ era Tesla E83CC. I'd wait to see how the 12BH7a work out first though..

    Sent from my BLA-L09 using Tapatalk

  3. #3
    Join Date: Nov 2010

    Location: Yorkshire

    Posts: 7,909
    I'm AnDreW.

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    Quote Originally Posted by Jazid View Post
    The 85A2 won't, it's a voltage stabilizer, the others might but the JJ are established favourites on the forums so you'd need to expect different rather than 'better' sound by rolling them.
    The obvious choices are box plate Mullard and pre JJ era Tesla E83CC. I'd wait to see how the 12BH7a work out first though..

    Sent from my BLA-L09 using Tapatalk
    You'd be surprised, I've heard many croft luminaries claim rolling 85a2 does change sonics!!!
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  4. #4
    Join Date: May 2011

    Location: Sheffield

    Posts: 203
    I'm John.

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    Others may well disagree, but I've found no benefit in changing the stock JJ ecc83s's in the power supplies.

  5. #5
    Join Date: Aug 2009

    Location: West Yorkshire

    Posts: 1,580
    I'm Stephen.

    Default

    Quote Originally Posted by Bigbird View Post
    Hi guys hope your all well.

    Im after a bit of advice from any Crofties or valve experts.

    Ive got the croft 25r with upgraded linestage
    And the 7r monos.

    After speaking with a few people the unanimous decision was that rolling the linestage 12bh7A will alter the sound the most and that the 50s NOS RCA valves seem to be most peoples go to choice for best of the best valve. It already has a nice nos Sylvania in there but i fancy a bit of fun to see if i can taylor the sound a bit more.

    Others also recommended that swapping out the line in valves on the monos has a nice effect. To get the clean detailed sound that i like i have been recommended the Nos GE 5751 in this position BUT luckily i took the top off to have a check as the valves in this position are also 12bh7A not ecc83 or variant types.

    Ive pulled the trigger on a nice(but expensive)pair of 1956 RCA black plates, NOS and matched and super strong. I will also pick up one more at next pay cheque to complete the trio that i need.

    Anyway enough rambling my question is, has anybody tried any different valves in the other positions?
    The rest of the valves in the pre are a Mullard 85A2 and 2 JJ ECC83S

    And one ECC83S and one 85A2 in the two mono.

    Will changing any of these effect the sound or are they just for power regulation? Its all new to me so not sure, and dont want to spend lots more on top NOS tubes if its not going to make a difference.

    Thanks for any help

    Karl


    Sent from my iPhone using Tapatalk
    Hi Karl
    I have a very similar setup to yours (25RS and 7monos) which I have had for a good few years and as you might expect have done a fair bit of tube rolling.

    My impressions are:

    The 7's (I know yours are 7R's) are pretty much immune to tube rolling benefits. Mine came with JJ ecc99 gold pins and I stick with them.

    With the line stage I have settled on a NOS Raytheon 12BH7. I found the GE's dull and flat. RCA's very variable the NOS long black plates were very nice but the grey plates a bit so so. There are many incarnations of the Sylvania (red, yellow, green print etc). I have a pair of the latter but am yet to try. Glenn seems to favour the Westinghouse 12BH7 which I'm pretty sure is very similar to the Raytheon.

    In the phono stage it really really depends on how you want to tune the sound. FWIW I pretty much settled on NOS Siemens ecc83's. I also use these in the regulator section as they do make an audible difference. 1960's RCA black plate 5751's are very mellow (I have 2 pairs) Philips Miniwatts have a lush midrange and dead quiet. If you want to go "left field"then the Psvane T2 12AX7's are very quiet with no signature of their own. Totally uncoloured. Not tried Mullards in the 25RS but I found them too warm for my taste in my old Vitale.

    As always it's down to personal taste - don't let anyone tell you one valve is "better" than another. All you can do is listen and decide if they float your boat.

    Steve
    Always a little further

  6. #6
    Join Date: May 2011

    Location: Sheffield

    Posts: 203
    I'm John.

    Default

    Quote Originally Posted by worrasf View Post
    Hi Karl


    The 7's (I know yours are 7R's) are pretty much immune to tube rolling benefits. Mine came with JJ ecc99 gold pins and I stick with them.



    Steve
    I found that a nice pair of 12BH7a's in the 7R mono input stages were much better than the stock ECC99's, and actually would say that in my system they made a more significant improvement than replacing any of the preamp valves.

    As Steve says at the end of his post it's all down to personal taste.

  7. #7
    Join Date: Apr 2012

    Location: London

    Posts: 583
    I'm James.

    Default

    Quote Originally Posted by REXTON View Post
    You'd be surprised, I've heard many croft luminaries claim rolling 85a2 does change sonics!!!
    Well fair enough, I agree it's more likely to have an effect on sonics than changing the power plug

    Also, if the regulator is out of spec then voltage has drifted, or it won't keep regulation, either of which could be audible, or indeed one valve could be noisier than another, so point taken

    Sent from my BLA-L09 using Tapatalk

  8. #8
    Join Date: Mar 2017

    Location: Melbourne

    Posts: 217
    I'm Karl.

    Default Croft valve rolling question

    Thanks for all the replies gents.

    This is why i put a thread up as there are so many different views on this situation and also so many different incarnations of the croft amps its hard to get a straight answer.
    Its still a bit inconclusive for me now haha. Some say yes, some say no.

    I suppose the only way really is to try myself. Unfortunately some of these valves are scarce and eye wateringly expensive nowadays and to buy a few to find out you dont like them or they do bugger all is not ideal.

    I think enough of you have said it does make enough difference for me to give it a go . As you know at this stage of the game itís usually small improvements anyways and every little helps.

    I dont have the phono in mine as i use a whest 2.2 so no valves to worry about there.

    From any of your experiences, did you find that the power regulation valves (ECC83S)made a more audible difference to the sound than voltage regulation(85a2)?

    The silver mullard 85a2 that are currently in there do look old as the lettering has mostly come away but its hard to be sure what type they are and if they are the stock standard ones glenn supplies or were upgraded by the previous owner??? Any recommendations for 85A2 valves ??

    Also can any of you recommend a nice 12bh7A with a clean ,clear,detailed sound? im trying to avoid too warm as i like the Ďhifií sound myself.

    I think i will take out the existing NOS GE 12bh7A from the monos and use the NOS 50s RCA long black plates in there as they are perfectly matched,dated and balanced and it seems a shame to break them up . i will track down something else for the preamp linestage. I will definitely try one in the linestage first though incase they make a bigger difference there.

    I know that a lot of these tubes will come down to tastes and may well just be different , but different can also be better if its giving you the sound that you are trying to achieve.

    Thanks again

    Karl


    Sent from my iPhone using Tapatalk
    Last edited by Bigbird; 18-05-2019 at 23:48.
    Linn Sondek LP12 ( Santos rosewood plinth ,Roksan Nima with Tiger Paw Skale and Yannis tonearm cable, Cirkus, Trampolin2, SSP12 inner platter, Tiger Paw tranquility, Vivid subchassis, Vinyl Passion thick top plate / Mose Hercules 2 gold power supply / Audio Technica ART 9 / Whest 2.2 phonostage / Croft 25RLS preamp with NOS RCA valves / Croft 7R monoblocks with NOS RCA valves/ Spendor SP2/3R2 / Chord cobra 3 interconnects / QED signature revelation speaker cable / Marantz CD DAC /Atacama Equinox rack

  9. #9
    Join Date: Apr 2012

    Location: London

    Posts: 583
    I'm James.

    Default

    85a2 and most (at least Mullard) regulator valves look ancient when they are not even middle aged. Not a cause for concern if they look like salvage from the Torrey Canyon, beauty is more than skin deep!

    Can't speak for valves in these particular circuits, though I did have a series 7 power amp. Notably Glenn's choices have always been exemplary and his valve matching is impeccable, so whatever he put in will be irreproachable technically and sonically. So saying he used to use the valves I referred to earlier in his line stages so they have provenance, though his stocks may have dried up.

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  10. #10
    Join Date: May 2016

    Location: Chippenham, Wilts

    Posts: 63
    I'm Anthony.

    Default

    I got my 7R's from Glenn via Adrian at Audioflair in late 2016. They came with;

    RCA 12BH7A stamped "USA"
    Mullard 85A2
    JJ ECC83S

    The distilled discussion as to valve rolling with Adrian and his recommended valve supplier, Matt Francesco, was;

    For the 12BH7A, alternatives might be Tungsol grey or black plates having more "grip" but the RCA's with more "presence". Another comment; "The 7R's being very grippy anyway I can see why some go for the RCA". Otherwise GE with a "dryer, cleaner" sound. I didn't audition the alternatives and stuck with the RCA's.

    For the 85A2, Mullard was deemed "best" so I stuck with that.

    For the ECC83S, NOS Mullard ECC83 were recommended for a "more noticeable uplift". I auditioned these and they stayed put.

    I have been very much enjoying the 7R's, now with a more recently acquired Micro 25R (2 x Electro-Harmonix 12AX7, 3 X JJECC83S, Mullard 85A2), all revealing music with great presence, life, detail and transparency whilst not dry or clinical. I have an RIAA-R, which seems to offer great opportunity for valve rolling. Can't quite remember the original valve compliment but it is now;

    Tungsol 12BH7A grey plate
    2 x Tesla E83CC
    2 X Mullard ECC83
    Mullard 85A2

    Since I have the RIAA-R my next step is to get Glenn to remove the phono stage from the 25R and upgrade to the 25RSLS linestage (perhaps with some other mod's). I will probably start with Glenn's USA RCA12BH7A's and see how it goes from there. Should hopefully be done in August.

    Have fun.

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