6B4G - The Resurrection Shuffle

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simon
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#241 Re: 6B4G - The Resurrection Shuffle

Post by simon »

Bummer!
Cressy Snr
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#242 Re: 6B4G - The Resurrection Shuffle

Post by Cressy Snr »

In the short time I've so far spent with the amplifier, I think I have recaptured that magic SET sound I achieved at Owston, all those years ago, with that pair of 6B4G monoblocks.
Although this project has turned out to be physically and electrically, nothing like those old monos, the sound is nevertheless, still all there.

The JJ 2A3s are dissipating 27 Watts each, meaning that the circuit would destroy "normal" 2A3s, but the JJs are very good, so that limitation is not a problem.
I'm probably getting around 6Wpc out of this thing, which is OK with my speakers. In fact a decent SET seems to work really well with the OmniMets, the big soundstage and colour saturation of SETs complements the omni presentation. Steve's PX25 amplifier got on well with them too.
Last edited by Cressy Snr on Mon Oct 30, 2017 10:58 pm, edited 2 times in total.
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Cressy Snr
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#243 Re: 6B4G - The Resurrection Shuffle

Post by Cressy Snr »

simon wrote: Mon Oct 30, 2017 10:23 pmBummer!
Indeed!
But at least I'll get the thing properly finished cosmetically. If it had continued working, I would likely have ended up with it sitting on wood blocks for months, before I would have been arsed to finish the job.
I have Paul to thank for steering me towards a 3 stage setup, with medium gain first stage, followed by a small power valve (EL84 or 6V6/ 6AQ5) as the driver to the 2A3s.
I've kept things as simple, minimal and direct as possible and personally feel I have recaptured my own DIY spirit, something that I felt had dissipated over the years. It's nice to get back to the roots of what it is that can make this hobby rewarding rather than frustrating.
Sgt. Baker started talkin’ with a Bullhorn in his hand.
steve s
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#244 Re: 6B4G - The Resurrection Shuffle

Post by steve s »

I'm glad it's turned out well Steve..
It looks great as usual
I'll look forward to listening to it sometime?
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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IslandPink
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#245 Re: 6B4G - The Resurrection Shuffle

Post by IslandPink »

Good effort Steve !
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Cressy Snr
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#246 Re: 6B4G - The Resurrection Shuffle

Post by Cressy Snr »

Thanks chaps :D

It's back in service after replacement of the SS diodes in the hybrid bridge with some spare 1000V, 3A, SiC Schottkies I found....diodes that NickDS pointed me to a couple of years ago. All appears to be well now. The dodgy rectifier valve was binned.

I put a period badge off my old valve wireless on the front, to hide a scratch :wink: and the old telegraph licence plate in front of the choke, to hide a redundant drill hole. All add nicely to the 50s Deco revival look that I want.
I'll run it for a few days, whilst I make the baseboard; not doing any more today. The feet will be chrome barrel feet, made from some straight chrome kitchen cabinet door handles. These are around eight inches long and about 5/8 inches in diameter; should do the Art Deco thang very nicely.
The white LEDs that bias the first stage, will provide two pools of white light below the front of the amp. They also provide the illumination for the twin front panel, Fender jewels.

Heres a pic of it with the period badges, The white light pools can just about be seen below the front red lights:
Image

@ Steve
I'll have to bring it through to Hull at some point before Christmas if you are not too busy.
Sgt. Baker started talkin’ with a Bullhorn in his hand.
steve s
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#247 Re: 6B4G - The Resurrection Shuffle

Post by steve s »

Cressy Snr wrote: Tue Oct 31, 2017 2:49 pm

@ Steve
I'll have to bring it through to Hull at some point before Christmas if you are not too busy.
That would be great and I would look forwards to hearing it Steve...
Let me know when... I also have a favour to ask when you come across....
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
Cressy Snr
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#248 Re: 6B4G - The Resurrection Shuffle

Post by Cressy Snr »

OK Steve,
I'll get it properly finished first and get back to you.
Sgt. Baker started talkin’ with a Bullhorn in his hand.
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#249 Re: 6B4G - The Resurrection Shuffle

Post by Thermionic Idler »

That looks REALLY nice. :D
Deck: Garrard 301 - Audio Origami PU7 - NW Analogue DH3S
Phono: Pete Millett LR, Lundahl SUT, AMB σ22 PSU
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Power amps: 300B PP 'Symmetric Reichert'
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Cressy Snr
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#250 Re: 6B4G - The Resurrection Shuffle

Post by Cressy Snr »

Cheers Dave.
I took a bit of a punt on the rose gold metalflake chassis colour, but it has worked beautifully and really fits with the mid century period look, I'm trying to to recreate.
Sgt. Baker started talkin’ with a Bullhorn in his hand.
Cressy Snr
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#251 Re: 6B4G - The Resurrection Shuffle

Post by Cressy Snr »

Also this thing represents a rediscovery of back to the basics approach and the K.I.S.S. philosophy... hummy AC filaments and all.

Twin cone tweeter array experiment in progress:
Image

This is what it's all about. :mrgreen:
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Cressy Snr
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#252 Re: 6B4G - The Resurrection Shuffle

Post by Cressy Snr »

Chrome barrel feet, upcycled from some old drawer handles, have been attached:
Image

View from the front completes the 50s Art Deco revival look:
Image

Job done! :) :)
Sgt. Baker started talkin’ with a Bullhorn in his hand.
Cressy Snr
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#253 Re: 6B4G - The Resurrection Shuffle

Post by Cressy Snr »

Rose gold metalflake topped with clear satin lacquer is the absolute biz, for custom 50s retro valve amps. It captures the period perfectly. I'm well chuffed
Sgt. Baker started talkin’ with a Bullhorn in his hand.
simon
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#254 Re: 6B4G - The Resurrection Shuffle

Post by simon »

I popped round to Steve's for a listen earlier - it really is groovily pink! It's great to see Steve with his valve mojo back too :-). We listened to some Beatles songs on vinyl and they sounded really very nice indeed. As Steve says, the big JJs sound like 2A3s but with a bit of 300B thrown in somehow.

I brought my 2A3 amp round as I thought it would be interesting to compare RCAs, Sovteks and JJs. Sadly after the change from the RCAs to the Sovteks there was some clicking and then some smoke from the base of one of the Sovs. Hitting the power quickly we flipped it over to find a vented cathode bypass cap, so that was the end of that experiment.

I've had a look around and it looks like it's only the cap that's let go and the amp's playing again with a new cap. Fingers crossed.

The most surprising thing I found with the speakers is the way they play low bass lines; really very impressive - clean, detailed and controlled. Even more so from a relatively small cab. Food for thought for another project...
simon
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#255 Re: 6B4G - The Resurrection Shuffle

Post by simon »

In better news at least I got 92mpg for the 25 mins/10 miles journey home :-)
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