The Marco-boy main system, as of August 2020

[Marco]

Ok, I mentioned earlier that I was hopeful of imminently landing some vintage gems, and the deed has been done! These lovely things will be winging their way from Japan to chez moi...

NOS Denon DL-103GL (Gold Limited) - introduced in 1990, in a very limited run of 2000 pieces. It is, IMO, one of the finest 103s ever made, alongside the 'M' and 'SA', the latter which the GL is near-identical to:





And a lovely mint example of a 1976-vintage Denon AU-310 SUT:







$1300 for both, shipped (insured and trackable) to the UK!

It's been a while since I played around with SUTs, as I've mainly been using MC head amps, such as the Paul Hynes and Lentek. However, I wanted to revisit using this little device, as it's something I first encountered in 1982, when I bought my first DL-103, and used it with that to great effect!

The sound I remember from then was so warm and musical (but not in a euphonically coloured way), rather richly toned and lifelike, with an addictive rhythmic alacrity to the bass, so I wanted to try and recreate that, used in conjunction not just with the GL, but also my NOS, stock (Nippon Columbia-vintage) DL-103.

The GL is something I've *always* wanted, but genuine NOS ones rarely come up for sale. One of my biggest regrets (and fortunately I haven't had too many in audio) was selling my DL-103SA and buying an SPU, not because I didn't enjoy the SPU, but because I should've kept the SA!

Quite simply, it was one of the best cartridges I'd ever heard, fundamentally addressing the shortfalls of the stock 103 (introducing carbon-fibre reinforced resin casing, wound with 4N gold coils), and the music it made was simply magical!

So... Now I have the GL, which is built near-identically, and am really looking forward to hearing what it does, in conjunction with the AU-310, and also the Lentek!

Happy days

Marco.

[RobbieGong]

Nice one Marco ! Look forward to how it all develops

[Marco]

Cheers, mate. It'll be fun playing with some new toys again, and these ones have been on my radar for years!

Marco.

[Wakefield Turntables]

Marco,

I've tried the following 6SL7's in the left and right output channels.

1. RCA 5691 (Red Base) 9.75/10
2. Bendix 5691 (Red Base) 9.75/10
3. Tung Sol 6S7GT (Black Bottle) 9.6/10
4. Tung Sol 6SL7GT (Orange base) 9.5/10
5. Mullard 6SL7GT (Black base) 9.25/10
6. Ken Rad 6SL7GT (Black Base) VT229 9.25/10
7. Tung Sol 6SL7GT VT229 (Black bottle) 9.1/10
8. General Electric GSL7GT (Black base 1970's) 8.75 / 10
9. Slyvania 6SL7GT black base 7/10
10. Brimar 6SL7GT (black base) 6.25/10
11. Reflektor black base 70's version 5/10

I honestly get fed up trying different types and at the time I think I'd gone through all variants. I'm now sure more (OLD) variants exist.

[Marco]

Hi Andy,

That's cool, but which ones didn't work until Alan modified you amp to accommodate their electrical parameters? That's what is flummoxing me...

I'm presuming none of the above, as all would work fine in my Croft, without any adjustments needed!

Marco.

[Wakefield Turntables]

They all worked but the Croft needed some optimising which is what Alan performed, as detailed in the earlier posts. I just wanted to make sure that the 6591 worked optimally. The Croft was out of spec and he remedied this.

[Marco]

Ah ok, so it was more a case of at the time there being something wrong with the Croft, rather than a fully functioning one needing modded to take 5691s?

If so, that's fine, as otherwise the Croft should happily take 5691s without the need for any adjustments, as indeed mine does

Marco.

[Firebottle]

It was the 5691 Marco, these have 600mA heaters, just looked them up again.

Does your Croft have the 5 valve line up. If so I imagine with 5691's in they would not be operating optimally.

[Marco]

Yes it has five 6SL7s, and an ECC83/12AX7 and 85A2 in the PSU section.. What I can categorically tell you is that the 5691s I've used have been in there for YEARS, and so if they weren't operating optimally I'd have known by now!

I certainly have not experienced the issues you described earlier with Andy's amp:

Andy fitted alternative valves with a 600mA heater rating and discovered that he needed to fit 3 valves to make the line section only work, because of the shared heater circuit with part of the phono section.

The other line valve was underdriven because the resistor value was too high a value for the 600mA rating, causing this channel to be low on gain and distorted.

That has simply never happened. Any 5691 valve I've used has sounded excellent and not behaved badly, in any way, in my amp. I suspect that Andy's Epoch has some design differences compared with my Charisma-X - remember that although both are Crofts, they are different models

Marco.

[Firebottle]

I imagine that is very true Marco. Could be that the Charisma uses 6V heater supplies, so individually wired.

If all the heaters are the same colour/temperature then no problem.