Tube rolling in Icon Audio

[Haselsh1]

Icon Audio Stereo 20 PP

Tube Rolling

A few days ago I took receipt of some National ECC82 valves for insertion into my Stereo 20 amplifier as it is still running with the original Chinese types. Now although I have not yet had the time to have a serious session with these valves, I am hoping this weekend will be fruitful. I was told when I bought the valves that they measured well but unfortunately I do not have those measurements so have no way of knowing how true this is. With a bit of luck all will be well. Does anyone have any experience with National valves ?

[Ali Tait]

I've used some 6AU6's in the past, as well as 5U4G rectifiers from National, which I found very good. S'all amp and system dependent I find though. IMHO, it's worth trying the likes of the better NOS Mullard or Telefunken 82's. Not cheap but very good indeed.

[snuffbox]

And what is tube rolling?

[Ali Tait]

Find a steep hill.... :lol:

It's just trying different makes of valves in your kit. Different makes have a different sound, so it's good to try several to get a sound to your taste.

[snuffbox]

Isn't this what we used to have tone controls for:)

[Ali Tait]

It can alter more than just tone, better soundstaging and imaging can be had amongst other things.

[Marco]

Hi Shaun,

I hope the tube rolling goes well, as I'm sure it will. In my experience, good NOS valves simply allow an amplifier's existing circuit to reveal more of its true potential :)

Ali,


I've used some 6AU6's in the past, as well as 5U4G rectifiers from National...


I haven't tried National ones, but I'm absolutely lovin' a pair of early 1960s RCA 5U4Gs in the Copper amp, instead of the usual Mullard GZ34s... They have a sweeter, more expansive top-end and a tighter bass, making the GZ34s sound somewhat 'constrained', two-dimensional, and a little overblown in comparison.

I just wondered if you'd discovered something similar?

I'm looking forward to trying some Mullard GZ37s, which Anthony is bringing up for me to try, as apparently, they give the best of both worlds between the GZ34s and 5U4Gs!

Meanwhile, I'm expecting delivery tomorrow of a matched quad of early 1950s NOS Brimar CV1988/6SN7GTs, for the copper amp:

http://img827.imageshack.us/img827/5794/imgp0002px.jpg (http://imageshack.us/photo/my-images/827/imgp0002px.jpg/)

Can't wait to try them out! :cool:

Marco.

[Ali Tait]

Marco, well they were certainly a big step up from what was supplied with the WAD 300b PSE monoblocks I had at the time. I did have some RCA's too, though not as vintage as yours I don't think. It was a long time ago now though, I haven't had an amp with 5U4's for quite some time, though from memory my experiences certainly mirror yours. I think you will like the 37's, I had a Mullard CV378 in the WAD 300b PP original stereo version that mike bought off me. Is that what Anthony is bringing? They are very good.

[Ali Tait]

PS, the Brimars look nice, bet they were pricey!

[Marco]

Lol - I got a good deal on them, but they still weren't cheap! Best thing is, they measure at near full (as new) emission, bearing in mind that 6SN7s measure at 10mA, when performing optimally:

Valve 1: 9.8/9.8mA

Valve 2: 10/10mA

Valve 3: 9.7mA /9.8mA

Valve 4: 10/10mA

:carrot: :yay:


I think you will like the 37's, I had a Mullard CV378 in the WAD 300b PP original stereo version that mike bought off me. Is that what Anthony is bringing? They are very good.


Yup, them's the boys!


http://img9.imageshack.us/img9/6045/95dc1b.jpg (http://imageshack.us/photo/my-images/9/95dc1b.jpg/)

Yes, I think I'll like them, too :)

Marco.

[Ali Tait]

Let us know what you think mate.

[Marco]

You can bank on it! :)

What rectifiers are you currently using in your amp?

Marco.

[Ali Tait]

Currently got three valve amps, only one of which is valve rectified. That uses EZ81's.

[Marco]

No worries... Don't think I've ever heard EZ81s. Maybe it's an SE amp thing... Are they directly or indirectly heated? :)

Marco.

[Ali Tait]

No, it's a PP EL84 amp. A handy thing with the EZ's is they are the same size as an EL84, so don't take up much real estate. It's the bigger brother to the EZ80, and can give up to 150mA.

[Marco]

Hi Ali,

I've had the Brimars in now yesterday and today, and all that I think I need to say is, if you're ever looking for some NOS 6SN7s, and you spy some 1950s black base, coloured glass CV1988s - just buy them!

Freakin' awesome :eek:

Marco.

[Ali Tait]

Cool, glad they're doing the business. Just got some EL84M's this morning. They are warming up as I type.

[Marco]

Hope they're hitting the spot, mate :cool:

Marco.

[Jonboy]

Cool, glad they're doing the business. Just got some EL84M's this morning. They are warming up as I type.


what you running them in Ali

[Ali Tait]

Jon, PP EL84 monoblock amps.

Marco, yes, they are rather good, better than the 6p14p's I was using. They're meant to be a ruggedised version of the EL84, with a much longer life, and from what i've read give 95% of the sound of Mullards or Telefunkens. Dunno cos I've never tried EL84 versions of those but they're definately better then the standard Russian valves. They should get better as they run in I hope.

[Jonboy]

If i was concentrating on the thread i would of seen that:doh:

I ran the same valves in my old Leak stereo 20 they were rather good, i will have to have a rumage in my valve draw and see if i still have some or i might have to buy some new ones for my Lafayette now you've reminded me

[Ali Tait]

Yes, rather good, and more importantly, cheap!