The Marco-boy main system, as of August 2020

[Marco]

We shall see, I need to get a pair first. I do own a pair of Tung Sol 67SLGT (Black bottle/Micanol base) but not the "Y" version. I rate these as very good tubes in the context of my own system. As an aside you might want to speak to Paul @ RFC, he's made lots of new modifications to Tannoy XO's since you last had yours done. We checked mine out and I'd gained a dB of efficiency. I've his top spec sitting in mine. I don't have any Duelund components sitting in my XO.

Hi Andy,

Firstly, remember that the valves I'm talking about, and illustrated earlier, were 6SU7GTY [the 'U' is significant], not standard 6SL7s; although they are electrically similar, and so considered as equivalents. The ones you're looking for are the 1940s versions, with black glass and black writing, on a dark brown base. Those are the best sounding.

Others of later vintages will not be the same, or indeed anything marked as a 6SL7. These are very much premium, military spec versions of the latter. A pair of 1950s ones were sold a while back on here: https://theartofsound.net/forum/show...084#post829084



You can see that those have white writing on them, rather than the black of the 1940s ones, which shows that they're later versions. Still sublime sounding, though!

In terms of crossovers, I hear what you're saying and I'm glad that you've had some useful gains, but I have my own people I use for such work, and with these types of projects, like I'm doing with the Celestions, I prefer choosing the components myself and creating my own 'sonic signature', as that's all part of the fun!

Marco.

[Marco]

I can't remember the name to whom made Marco's but I know he was very well regarded.

The guy who did mine is a member here called 'swampy', David. He's top notch, and one of the best I've ever seen at soldering stuff. Amazing neatness and attention to detail! He did all the point-to-point wiring on the crossovers for my Tannoys

If I really like what the Jupiters do, I intend on trying them in there, perhaps instead of the Clarity Caps, or something else. We'll see!

Marco.

[Marco]

I think it's important to say that familiarity does breed some degree of contempt and a change is as good as a rest with component swapping.

With a large collection of valves when you really get to know their various personalities sometimes it's like meeting old friends if you haven't heard a particular valve in a good while.

Yes, I agree with that. The other thing is that, chances are, in the interim, you'll have changed your system in some way, added a new component, cables or whatever, so what was 'best' before, in a particular context, won't necessarily be so now...

Marco.

[Wakefield Turntables]

Here we are a little picture of my Duelund bypass caps in the 15's. Very nice they sound.

[Marco]

Interesting... Aside from the cap changes, they look quite different from the crossovers in mine!

Did you assess the speakers first, just by changing the existing caps for the Jantzens, or do both mods at once?

Marco.

[Wakefield Turntables]

No I did the Jantzen's first and then modded them with the bypass caps about 3-6 months later. I did the bypass caps about a month ago. The Jantzens replaced some clarity caps. Here's the original thread https://theartofsound.net/forum/show...lestion+ditton I've now got the 15's setup and intend to listen to them over the next couple of weeks to get a handle on what the bypass caps are doing. The old wardrobes have been pushed aside!

[Marco]

Ok, noted. So what did both mods bring to the party, sonically, but especially the bypass caps?

Your 15s are defo much later than mine, probably by about 10 years, with yours being from 1977. Aside from the crossover components, even the original binding posts look more modern.

This is what mine currently look like:



Compared with your old ones on the left:



...which are positively 'high-end' in comparison!

Marco.

[Wakefield Turntables]

Marco,

Family time and lunch beckon so I'll write something tonight.

[Marco]

No worries, matey. I'm in a similar position myself

Marco.

[Marco]

Just scored a nice matched pair of these vintage tubes. 'Coin Base' RCAs are often frowned upon by audiophiles, but I actually like using them (and vintage RCAs in general), in key areas of the Croft's phono stage.

They have a nicely open, punchy and dynamic sound, and not in any way thin-toned [as is often their criticism] when used in the right circuit, and which doesn't need the rather 'plump' bass enhancement of 'phat' sounding tubes. When tube rolling, and subsequently optimising the sound, it's all about successfully combining 'flavours'!

Anyway, here are the little 'tall-bottled' bastards...







Nicely constructed... Look at those nice fat shiny pins!

Oh, and as an aside, this is a rather interesting site, detailing the history of many different valves, but this bit is involving 6SL7s and their history, which folks here using them should read: http://vinylsavor.blogspot.com/2016/...onth-6sl7.html

Just to report that the RCAs landed yesterday, and..... They're bloody brilliant!

Firstly, these 'coin base' RCAs are very well made, and heavier than most other valves of the same type, due to what appears to be a thicker/denser type of glass, plus the (visually at least) heavier-duty construction of the internals, and also the thickness of the pins. In that respect, they're superior to earlier 1960s versions, which is rather unusual, and the first time I've experienced that with valves of a later vintage (in this case 1970s), being better built than previous ones.

Sonically, they're very dynamic, punchy and 'alive', allowing appropriate music (such as metal, in this case Tool) to motor along with an addictive impetus and rhythmic drive, which is rather grin-inducing! However, they're also extremely detailed and able to pull out the subtest of musical information buried in the densest of mixes, as well as imbuing voices with the requisite 'air & space' in order to sound convincing and real. The top end is also suitably 'crisp', but never bright or spotlit.

Therefore, these are defo keepers, and rank among the best NOS 6SL7s I've heard!

Marco.