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Arkless Electronics Transconductance Phono Stage

Sounds like you've got a hit on your hands Jez, Congrats.
I am very much enjoying the 47 Labs PhonoCube that you breathed life into, but please sign me up for a demo of your stage when possible.
 
All requests for loan of demo unit noted;) There's a bake off this weekend then a few more in the Sheffield/South Yorks area to try it yet. I'll then get round to organising home loans for genuinely interested potential buyers:)
 
You've got a very fine thing here Jez, the fact that it's still just travelling prototype makes it even more convincing for me.
 
Ah yes I see:) The only planned "improvements" are a slight change in RIAA caps and maybe a change of resistors but the latter is unlikely.

I may as well "drop the bombshell" now and get it out of the way that potential purchasers will have to order (or not) based on home trial of this prototype unit. Early adopters will not be able to see or hear a full production version before ordering... these are particularly difficult, expensive and time consuming to build, with many components having to be hand matched etc, and so I won't be able to take it any further without guaranteed orders lined up based on successful demo of this unit. However the production version will be in the same casework etc and this can be taken as fully representative of the final production version with the only difference being that the production units will be on PCB's rather than stripboard (a PCB with all the tracks in parallel lines which are interconnected with wire links etc). See pic below of the of the prototype PSU innards on stripboard.

o2GxHEV.jpg
 
Perhaps it’s worth pointing out, to those who may not realise, but the picture above is just of the power supply, not he main phono section :).
 
YNWOAN said:
Perhaps it’s worth pointing out, to those who may not realise, but the picture above is just of the power supply, not he main phono section :).
Click to expand...

Indeed. It was to show the strib board construction of the prototype/demo unit by way of explanation of the main difference between it and a full production model in which the PCB will be the usual red or green and without the parallel rows of holes of the strip board. Otherwise very much the same. Although on one board the PSU is true dual mono. There is further voltage regulation in the actual phono stage so this acts as a pre-regulator. The phono stage itself obviously is also dual mono and has completely separate boards. No photos of that as A/ it's commercially sensitive and B/ as it is the real prototype bit there are areas that have been modified after initial tests, thus, although well made and built to last, this renders it rather less aesthetically pleasing! This will of course all be sorted in the final PCB's!

I look forward to your further impressions after a longer listening session tonight Mark:)
 
slawekt said:
Can we have a look at phono stage innards
Click to expand...

See above...

What I will say is it has 18 transistors per channel, zero feedback (and yet <0.01% THD), passive EQ, no capacitors in signal path other than those intrinsic to the RIAA EQ (not even decoupling caps other than in voltage regulators, unlike the Paradise), an op amp for DC servo (not in signal path) and a potential 3 patents in original topologies... Steps have of course been taken to, ahem... discourage excessively close examination. Not that Sony Corporation are likely to be sending spies out for anything in which the USP's are pretty niche to MC phono stages... which are in themselves pretty niche.
 
Everything went down well at the Yorkshire Hifi Club bake-off, that was a great event. A long day of acute listening but well worth it for the selection of phonostages on hand, from £80 to knocking on the door of £10k and everything in between.

There was basically three units there I could live with, one of which I do live with, one of which i couldn't afford half of and one that's not available yet. I'm sure the keen eyed can work it out. I'm not sure what the general view of things were but there were definitely some slacked jawed moments during the day.

VFM of the day though for me, without a doubt was Ali Tait's £500 second hand Modwright phonostage, jesus christ what a good buy that was, 1/6th of it's original price. Deals like that don't come around very often.
 
What's the state of play with this interesting development? Are people posting their listening experiences elsewhere?
ML
 
DET - double ear testing. ;)

I tested it against my 4 box Paradise as did others, we all concluded there was very little between them, though given the similarity in design it is hardly surprising.

The biggest difference is that the Paradise is unobtanium, though Jez is working on the optimal way to market his creation.
 
You don't sell an MC step-up only version of this, do you? Or plan one? I may have asked you this in another thread.
 
Rosewind said:
You don't sell an MC step-up only version of this, do you? Or plan one? I may have asked you this in another thread.
Click to expand...

If you mean an MM version which could be used with an SUT then no. The technology does not really lend itself to MM stages in this form.

I do have a prototype valve hybrid MM stage built which uses the transconductance technique but I've no idea if I will take it any further at the moment.
 
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