A visit to Marco's

[Marco]

Some pics... KIN phonotage underneath AIR power amp:





Denon DL-103 in AT titanium headshell, also with Mpingo wood spacer:





And again, a little more clearly:




AIR power amp on its own, with Raspberry Pi in the background, and Copper amp just about visible underneath:






Marco.

[Marco]

Great write up Marco, and a very generous appraisal of Alans equipment, both of which I have heard here put up against the Croft Micro 25R+ and the 7 so I know what they can do.

Alan is a very talented designer and I wrote a review of the KIN but not quite in its finished form - a truly great preamp with the added finest of superb phono stage.

I only heard the AIR briefly but even in its early incarnation it was excellent with great soundstage and indeed 'AIR'!

Good job you didn't have the DL-S1 on the techy, Alan would have the hair standing on his head!

Lol - cheers, mate. Just tried to describe things as best as I could. Yes, the DL-S1 or DL-103C1, fitted to the same headshell, would've been even better

Marco.

[lurcher]

My theory at the moment is that the difference is probably down to the input valve being driven via its cathode in the cascode circuit as opposed to the grid in a standard MM circuit. Anyone have any ideas on this or experience with experimentation?

I would remind you of the phrase "all a valve knows are the voltages and currents on its pins". As to if the signal is on the grid or the cathode, it all depends where you are standing, all the valve knows is the voltage between the grid and cathode changes. Either the grid waves up and down, or the cathode waves down and up.

[Firebottle]

Thanks Nick, I'll put that thought to bed then

[Marco]

Hi Nick,

Glad you've jumped in here... Any theories/ideas as to why, certainly in my experience so far, providing that an MC head amp or SUT is of suitable quality, and optimally matches the partnering MC cartridge, sonically and electrically, the signal always seems to sound better amplified that way, than directly via an MC input, no matter whether the phono stage in question is valve or SS?

To my ears, the sound always has a certain 'magic' with a quality head amp or SUT 'at the helm', as it were, which otherwise is lacking... I also note that many expensive/specialist commercial phono stages feature built-in and adjustable SUTs, so I guess that there must be something in it.

Marco.

[lurcher]

Well, I do have a theory. Not everyone will agree, but thats not my problem :-).

Phono stages are very hard things to make well, Making a good MM phono stage on its own is a hard thing to do well, but if thats the goal, thats the bit thats done well. Making a step up transformer is also hard if done well, and so is making a head amp. Stages that combine the head amp and the mm stage, tend not to have twice the work going into them, so there are more compromises. The jfet front end idea is a good way of combining valve with MC levels of noise, but its not perfect. I make them myself, but after two years of work making a MM input stage, I can hear the jfet in a jfet input. Its almost inaudible, but its still there and you can tell if you get everything else right. SS Head amps have more to them than a simple jfet, so they can often do a better job, and being standalone, the designer is more focused. SS only is so much simpler, so simple the designer generally doesnt work hard enough, and that suffers again from that. Its just about possible to get a pentode front end quiet enough for a cartridge like a 103, using that its possible to hear what both the head amps and step ups are getting wrong. With good ones its very slight, but you can tell when its not there. Lots of other parts of a phono matter just as much as the front end, but thats another rant or two.

Then again, some folk have their own preferences in the sound, that may mean that one or the other approach is a better match for their ears and or system. Thats all good as well.

[Firebottle]

I really enjoyed your system Marco, I didn't say on the day but when we moved to vinyl I got the same feeling that I always do. With any system of reasonable quality vinyl always gives that better 'organic' feel and yours was no exception.

The brilliant thing is with such a sorted system that you know so well is that you can recognise and pinpoint the variations with different kit and I thank you for that.
I guess the spaciousness of the mid range on the copper amp in comparison is down to the copper being class A. Of course the benefit of going down the hybrid route is not requiring the expense of the quality iron needed in an all valve power amp.

I didn't quite realise your spend on the Rpi so that explains why it was so close behind the others sources

As an aside I shall be bringing out a phono only pre, you both saw the chosen enclosure for the Vivant.

[Marco]

Thanks for that insight, Nick, and explaining it a way that a 'layman' can just about understand!

I agree essentially with what you're saying, and in some ways is best summed up as: 'choose your trade-offs/compromises carefully', because in audio, there is rarely a 'free lunch'. However, I like how you've looked at it here:

Stages that combine the head amp and the mm stage, tend not to have twice the work going into them, so there are more compromises <Snip>

SS Head amps have more to them than a simple jfet, so they can often do a better job, and being standalone, the designer is more focused. SS only is so much simpler, so simple the designer generally doesnt work hard enough, and that suffers again from that.

Hadn't thought of it like that before, in terms of how "focussed" the designer is or isn't, when his or her attention is also being diverted towards other areas of a product. I definitely do think that's relevant.

Then again, some folk have their own preferences in the sound, that may mean that one or the other approach is a better match for their ears and or system. Thats all good as well.

Yup, as indeed is the case when, simply through not much more than luck (or perhaps educated judgement), one hits upon a symbiotic combination of SUT/head amp and cartridge, where for no particular technical reason, sonic and musical synergy is achieved.

It can be a funny, and rather unpredictable game sometimes, this hi-fi malarkey!

Marco.

[Firebottle]

Excellent post Nick and I definitely agree.

[Marco]

Oh, just one further thought, Nick...

Would you consider that there's any mileage in the notion that because, with say, a quality head amp in the equation, being supplied from its own dedicated linear PSU (as is the case with my Paul Hynes), that this reduces noise in the signal path, or that the integrity of the signal is somehow else better preserved, than when going through a standalone MC stage, where the whole circuit shares the same PSU?

Almost like you're regulating the circuit better, with the signal amplification stage (head amp) having its own dedicated power supply? Experience tells me that individually regulating different parts of a circuit like that can have a significant influence on the performance of any piece of audio equipment.

Or am I talking bollocks?

Marco.