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Croft Super Micro Valve Pre

M

metaturtle

New Member
Heya. Apologies if this has been asked before.

I recently discovered the world of Croft and I'm currently in the market for a Croft amp (be it integrated or pre). I stumbled upon a Croft Super Micro Valve Pre and I am considering buying it.

Does anyone know any more info on these unites and how they compare to the later ranges like the Epoch or the Croft Micro 25 Pre?

Thanks!
 
In the case of all his preamps, Glenn used countless different circuits in his career and used various of those in each of just a few names/models.

In other words, the label means absolutely nothing whatsoever in terms of what is in the box, no matter the age.

About the only consistant thing (almost) is that the phono stage is two ECC83 (although if you search online, you can find that he did make some units with Soviet valves).

The major change in more recent models was that he moved largely or entirely away from valve-based power supplies.

Perhaps, and I emphasise perhaps, the commonest configuration is two ECC83 MM stage, one ECC82 cathode follower output valve and an ECL85 power supply. This can be found in various cases with numerous different names on them. On older versions, there is an 85A2 voltage reference valve in the power supply too.

As an incredibly over-simplified rule, the more valves, the "better" the sound. In my two Croft pre's, I can hear essentially no difference with what valves are in them - "valve-rolling" does all but nothing.

The integrated amp's, I know nothing of, but Arkless suggested that they are pretty basic electronics, and he designed amp's for a living at one time.
 
Thank you Vinny, this is helpful. Would you say that the amps with valve-based power supplies are more difficult to maintain?

On a different note, what kind of power amp would be suitable for a Croft pre? I'm thinking of going solid state as I don't want to maintain an all valve setup and I'm currently looking at the Quad 404.
 
Croft pre's never go wrong and valves dying in them are basically unheard of. I asked Gleen about servicing and he said that there was nothing to be done unless something was obviously wrong.

My second Croft purchase had faults, but easily found and fixed by anyone with a soldering iron, and possibly due to abuse or mishandling. One volume pot had a dry joint and one of the toggle switches was a dud. Maybe 20 minutes to find the problems, and about £1.50 and as long to fix.

So far as suitable power amp's go, I suspect that any modern SS will work fine. ONLY RECEIVED wisdom on my part, but older power amp's are not so suited - older Quads for instance. You'd need far better comment than any I can offer on older designs. I know nothing about a 404.

I have used mine with Audiolab and Exposure power amp's and now use some NCC300 Avondales.
 
Pictures would help - the older deigns with 85A2 do slowly fail, but apart from that, pretty robust things - excellent pre, and an even better MM phone stage :)
 
Cannot remember exact detail, but when I bought my first Micro I had it shipped to Glenn for a service - the 85a2 had gone, but also some sort of tube/bulb that drove it - he offered 2 options, switch to silicon and never have to worry again or keep it original. I asked which sounded best, so kept it original :) Repair cost was £60 from memory, including bringing output stage up to latest spec (back in 2007), so not an expensive repair regardless. There should be posts from me somewhere here that has more detail, maybe even piccies.
 
I have a Mega Micro II with 12 valves in the PSU, never had one fail in the 5-6 years it was in constant use.

however, it was then ousted by a SMA IV (Super Micro A IV) with 6SN7 valves in the line stage and 6SL7s in the phono stage. (Glenn Croft built me a bespoke PSU, no valves in that though). I much prefer the sound of the octal valves to ECC83s.
 
I have not, and have no inclination to, trace the circuits and compare deatils, but the output made quite a difference here, between the two Micros that I have - ECC83 cathode follower v. two 12BH7 push-pull. (Latter the best by quite a margin.)

Glenn produced almost countless verions of pre-amp - I have never seen one advertised or otherwise, but he did some verions using Soviet valves, as they are mentioned online - they are all well worth a listen.

Next time that a Mega Micro comes up, I will bite the bullet, whatever version it is (they are so rare that I suspect that he made so few that each is a one-off, unique)).
 
Indeed, my Mega Micro is going nowhere! I recently plugged it back into my system after using a dCS Delius as a digital only front end direct into my power amps for 4-6 months - I prefer sound with Mega as pre is an under statement…
 
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