6B4G - The Resurrection Shuffle

[Cressy Snr]

Now that sounds like a plan Nick
I'm hoping to see Steve about some OPTs within the next fortnight, so I'll try to get up to you during the same week.

It may sound perverse, but I'm quite enjoying the practical exercise.
It'd be interesting to see if my calcs and graph drawing come anywhere near what uTracer will spit out. It might be a reassuring endorsement of my abilities or a major embarrassment; hopefully, the former.

[Cressy Snr]

Got half a dozen Philips ECG 12GN7 in the post this morning. £15 from Billington Export, for six isn't bad at all. Seems high gm TV pentodes are cheap as chips again. 12GN7 were a tenner a piece back in 2011.

So I now have all the glassware. Just need the OPTs and we are ready to go.
The original amp used all guitar amp parts such as Sprague Atom electrolytics and orange drop caps, carbon comp resistors. Volume controls were vintage Allen Bradley carbon tracks. I might have these pots still around somewhere.

[Ant]

You dont need any pots, you have 2 passive pre's

[Cressy Snr]

Oh yeah
I'm getting to be a right silly old sod.

[jack]

Well, that was a fail on my part...

...got back to Dubai last night to find that I can't find my stack of Linear Audio mags here either, so I suspect that they really are in the UK, just that they've been moved somewhere... just that I now can't check until Christmas...

Absolutely hate it when that happens

Nick should have a copy of the articles as I believe he subscribed too. Apologies.

[Nick]

Yep, I should be able to drag that copy out. I know where they are (unlike the spare quasi boards that I still cant find).

[Cressy Snr]

I'll hopefully be able to get to your place Nick, next week, or maybe this Sat if you are not doing shows etc.
Will be picking up some OPTs from Steve this Friday, so if I can get the mains TXs tested for the right snubber networks, on Sat, it would give the project the green light to get going, next week.

It's nearly two years since I did a build, so looking fwd to getting going.
The biggest fear I have is that my NVA A20 will p*ss all over anything I could come up with. Yes folks, it is that good I'm afraid. But if I don't try, I am not going to find out.

It was interesting when Neal came over last Wednesday to listen to the system and asked me what hobby I intend to take up now, as we could not think of any substantial way forward with the system, in my home, as it currently stands.
Now, that cmment could be taken any number if ways I suppose
The talk was about music rather than hi-fi, once a couple of tracks had been played, which is of course how it should be.

[Nick]

I'll hopefully be able to get to your place Nick, next week, or maybe this Sat if you are not doing shows etc.

Yep, Saturday should be fine AFAIK

[steve s]

Will be interesting to see how the A20 compares with my se px25 on friday Steve...
If anybody's free on Friday.. all are welcome?

[Cressy Snr]

Will be interesting to see how the A20 compares with my se px25 on friday Steve...
If anybody's free on Friday.. all are welcome?

It'll be an interesting comparison 'fer sure.
We will need to do the comparison, using my LS2 speaker cables for both amps. I don't want to invalidate my warranty.

[Cressy Snr]

I'll hopefully be able to get to your place Nick, next week, or maybe this Sat if you are not doing shows etc.

Yep, Saturday should be fine AFAIK

I'll text you Friday Nick.

[Cressy Snr]

It's nearly two years since I did a build, so looking fwd to getting going.

Set out all the iron yesterday on a hefty tray.
With two mains transformers, two big chokes and a pair of hefty OPTs, the weight is a two man lift.
These facts are continuing the stealthy subversion of morale are beginning to sap any enthusiasm for the project.
The old heart is getting closer to abandoning it as a piece of hopeless nostalgia, for something that realistically, if I'm being honest, is highly unlikely to be recaptured.
I'm finding it difficult to stay focussed when there are speakers to design, omnidirectional concepts to explore that interest me far more these days than valve amps. I may change my mind after visiting Nick today, but I wouldn't hold your breaths.

[ed]

I think there is much sense in that thought process Steve...

I am going to list all the amps, iron and valves in the box with a view to ebay...it's not such a wrench as I sold 21 transformers two Christmases ago and haven't felt one pang of regret so far....

got enough mosfets and jfets in the box to last me out....

[Nick]

Just measured Stev's 12gn7, at 115v on g2.

[Cressy Snr]

Cheers Nick,
Interesting couple of hours at your place today.

Looks like I wasn't that far out with my manually derived curves.
Conveniently, it looks as if, lowering the screen voltage, just a tad, by using an 0B2 VR tube, will bring the curves in line with my own plots. Funnily enough, it is the first plot I did that is the most accurate, rather than the second, which I thought I had correctedd. I was right first time. Gonna have to actually trust my maths rather than looking for mistakes that probably dont exist.