2A3 "Pink SET" Amp Rebuild.

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izzy wizzy
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Re: 2A3 "Pink SET" Amp Rebuild.

Post by izzy wizzy » Mon Feb 12, 2018 10:04 pm

Glad you're back in team hollow state ;)

cheers,

Stephen

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Nick
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Re: 2A3 "Pink SET" Amp Rebuild.

Post by Nick » Mon Feb 12, 2018 10:08 pm

Cool. Glad it's worked out. It does show how much hum and crud will affect the perceived sounds.
Resistance isn't futile it's V / I.

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Re: 2A3 "Pink SET" Amp Rebuild.

Post by Cressy Snr » Tue Feb 13, 2018 10:22 am

Paul Barker wrote:
Sun Feb 11, 2018 6:02 pm
the pink set as i heard it was way too good to give up on.
You wouldn't have thought so, if you'd heard it the other day. You'd have been asking me what the bloody hell I had done to it. :)
Nick wrote:
Mon Feb 12, 2018 10:08 pm
...... It does show how much hum and crud will affect the perceived sounds.
Not 'arf Nick.

Anyway, it actually does sound better than it did prior to being messed with. There are too many things different about it, to attribute the improvement to anything in isolation. But the correct grounding arrangements will have had the most effect.

List of mods as follows:
  • facility to use 6V6 as driver
  • build is now, audio circuit components on tag strips, with flying leads to valve sockets
  • Power supply now - SS rectifier- choke - followed by (per channel) 200uF - 47R - 100uF - 2A3 - 250R - 100uF - 6V6 - 3K3 - 200uF - 6AU6
  • grounding arrangements are done properly
Oh it's a doobidee doo, yes it's a doobidee doo, I mean a doobie doobie doobie doobie doobidee doo.

steve s
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Re: 2A3 "Pink SET" Amp Rebuild.

Post by steve s » Tue Feb 13, 2018 3:13 pm

Glad it's sorted Steve....
The tube manual is quite like a telephone book. The number of it perfect. It is useful to make it possible to speak with a girl. But we can't see her beautiful face from the telephone number

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Nick
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Re: 2A3 "Pink SET" Amp Rebuild.

Post by Nick » Tue Feb 13, 2018 4:25 pm

I thought the DC heating was new as well?
Resistance isn't futile it's V / I.

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Re: 2A3 "Pink SET" Amp Rebuild.

Post by Cressy Snr » Tue Feb 13, 2018 5:09 pm

Nick wrote:
Tue Feb 13, 2018 4:25 pm
I thought the DC heating was new as well?
I abandoned that due to the lack of a suitable transformer to supply the AC to the modules. The one I was trying to use, got too hot, too quickly. I might try DC again, but it'll be done on a bit of wood.

The basic, three stage design seems to have proved itself in terms of the sound quality, but valve rectification is right out with this particular design, due to the high value caps combined with the current draw necessary because of the power drivers.

The next thing I would be wanting to try, would be with DC filaments, valve rectification and the big Eyuda motor run, oil caps, I bought with Simon, years ago, making up the power supply.

The ultimate dream, I suppose, is PX4.... :notworthy:
Oh it's a doobidee doo, yes it's a doobidee doo, I mean a doobie doobie doobie doobie doobidee doo.

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Re: 2A3 "Pink SET" Amp Rebuild.

Post by Cressy Snr » Tue Feb 13, 2018 5:16 pm

steve s wrote:
Tue Feb 13, 2018 3:13 pm
Glad it's sorted Steve....
Aye, it is working really well now; better than I could have imagined, given the awful sonics I had the other day.
The PSU changes, the tagstrip mod, and (courtesy of Nick) the proper earthing scheme, have taken it beyond what you and Ed heard a couple of months ago.
I need now, to do a 6V6 driver shootout :wink:
Oh it's a doobidee doo, yes it's a doobidee doo, I mean a doobie doobie doobie doobie doobidee doo.

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Re: 2A3 "Pink SET" Amp Rebuild.

Post by simon » Tue Feb 13, 2018 6:28 pm

Cressy Snr wrote:
Tue Feb 13, 2018 5:09 pm
...the big Eyuda motor run, oil caps, I bought with Simon, years ago, making up the power supply.
I really regret not buying a crate of them at the time. I've looked for them a number of times since but they don't seem to be available any more.

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Re: 2A3 "Pink SET" Amp Rebuild.

Post by Cressy Snr » Tue Feb 13, 2018 9:06 pm

simon wrote:
Tue Feb 13, 2018 6:28 pm
Cressy Snr wrote:
Tue Feb 13, 2018 5:09 pm
...the big Eyuda motor run, oil caps, I bought with Simon, years ago, making up the power supply.
I really regret not buying a crate of them at the time. I've looked for them a number of times since but they don't seem to be available any more.
Aye....from what I recall, from the last time I used these caps, around 10 years ago, they were excellent sounding things.
I've got three of them in a plastic box upstairs; ideal for breadboarding.
Oh it's a doobidee doo, yes it's a doobidee doo, I mean a doobie doobie doobie doobie doobidee doo.

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Thermionic Idler
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Re: 2A3 "Pink SET" Amp Rebuild.

Post by Thermionic Idler » Tue Feb 13, 2018 11:24 pm

Nick wrote:
Mon Feb 12, 2018 10:08 pm
It does show how much hum and crud will affect the perceived sounds.
I had experience of this the other day actually. I'd made up some XLR cables to connect the balanced outputs of the Whest phono stage and newly acquired CA Dacmagic to the two balanced inputs I'd provided for myself on the recently-built AMB linestage.

Whaddaya know. As soon as I hooked up those cables, the ground loop hum I'd had with my previous preamps was back! Which was annoying. Although not a loud hum, it was present on every source, and the overall sound quality of the whole system had noticeably degraded - become a bit more muddy, I think.

The problem stemmed from the fact that I still had an unbalanced pre to power amp connection, and the signal ground was connected to chassis and thus to mains earth, in the Son of Beast power amp. Fine as long as it wasn't connected to mains earth anywhere else... unfortunately I suspect the Whest has its XLR pin 1 DC connected to chassis and mains earth as well. Boom - there's your earth loop. Reconnecting the Whest using its unbalanced output solved the problem.

The new Beast monoblocks I'm presently working on have balanced transformer-isolated inputs and ground-lift switches, so that should then allow me to go balanced with the Whest, but it's another good example of how much of a nightmare grounding can be.
Deck: Garrard 301
Audio Origami PU7
Van Den Hul Black Beauty
Phono: Whest PS30RDT
Pre-amp - Scratch built AMB α24/LCDuino
Amp - Transcendent "Son of Beast" 15W OTL
Speakers - FF225WK Metronomes

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Re: 2A3 "Pink SET" Amp Rebuild.

Post by steve s » Tue Feb 13, 2018 11:47 pm

Cressy Snr wrote:
Tue Feb 13, 2018 5:16 pm
steve s wrote:
Tue Feb 13, 2018 3:13 pm
Glad it's sorted Steve....
Aye, it is working really well now; better than I could have imagined, given the awful sonics I had the other day.
The PSU changes, the tagstrip mod, and (courtesy of Nick) the proper earthing scheme, have taken it beyond what you and Ed heard a couple of months ago.
I need now, to do a 6V6 driver shootout :wink:
I have a few 6v6's Steve just need to find them...
The tube manual is quite like a telephone book. The number of it perfect. It is useful to make it possible to speak with a girl. But we can't see her beautiful face from the telephone number

simon
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Re: 2A3 "Pink SET" Amp Rebuild.

Post by simon » Thu Feb 15, 2018 10:25 pm

I did a bit of googling last night and found what looked like it might be Eyuda, so sent them an email with a photo of those caps. They confirmed it was them, and they'd made the caps for an American customer but hadn't heard from them for 10 years. They don't have any in stock and it's a minimum order of 500 to make any more. Slightly more than I need! Shame.

They have some CBB65 series which look similar, but that looks to be a classification of cap rather than their own category. CBB65 are readily available on eBay, but who knows how they sound.

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Re: 2A3 "Pink SET" Amp Rebuild.

Post by Cressy Snr » Fri Feb 16, 2018 9:17 am

Thanks Simon - useful findings. Midori Meadows must have been selling off the spare caps from that American customer.
The original customer might have been an aircon manufacturing company that folded; we'll never know.

CBB65 is also useful to know about; plenty of caps on Ebay as you say.
Oh it's a doobidee doo, yes it's a doobidee doo, I mean a doobie doobie doobie doobie doobidee doo.

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Re: 2A3 "Pink SET" Amp Rebuild.

Post by simon » Fri Feb 16, 2018 9:52 am

All we need is say 50 people prepared to stump up for 10 of them :-)

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andrew Ivimey
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Re: 2A3 "Pink SET" Amp Rebuild.

Post by andrew Ivimey » Fri Feb 16, 2018 10:19 am

Piece of piss! Phone 'em up, Simon, and tell them to warm up the capacitor making machine. 🐶🐶🐶🦐🦐🦐 just discovered emoji? what on earth do they all mean!???

Beautiful day today. I'm deep in the Chilterns, 37 miles from home...oops wrong thread, sorry. But I'm not cycling home. If I get to Stoke Mandeville I get lunch and a lift home ( in an ambulance!!!! NOT)

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