6B4G - The Resurrection Shuffle

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ed
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#331 Re: 6B4G - The Resurrection Shuffle

Post by ed »

pesky bloody cranes!...it happened about 2 minutes before I reached it taking the boss to manchester airport....sassenfrassencursinclaudehopper! luckily the traffic chaps were letting one lane through for a while elsewise probably wouldn't have made it to the airport.....funnily enough although the beeb traffic reports were constantly saying the whole road was closed there was not a sign of closure on the way back from the airport....it's all very well people informing the beeb when there is an issue, it would be just as helpful if people would inform them when the issue is cleared.

on another tack I have plastic here that would see off both px4 and px25....snigger
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pre65
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#332 Re: 6B4G - The Resurrection Shuffle

Post by pre65 »

ed wrote: Thu Dec 21, 2017 11:33 pm
on another tack I have plastic here that would see off both px4 and px25....snigger
Just a thought Ed, have you heard any NVA amps ?
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#333 Re: 6B4G - The Resurrection Shuffle

Post by steve s »

ed wrote: Thu Dec 21, 2017 11:33 pm

on another tack I have plastic here that would see off both px4 and px25....snigger
Can't beat a good credit card ed...

I was down in Worcester yesterday picking up another tiddler ( honda s90). I took a few country lane shortcuts, I did wonder if Simon would have been called out to the bridge, nice to know it was in good hands
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#334 Re: 6B4G - The Resurrection Shuffle

Post by Cressy Snr »

All caps are the same height now that the 800uF ones feeding the input stage have been changed for 200uF:

Image

After this pic was taken, I fished out a NOS MOV, 5U4G with the old rounded base that I'd bought for £20, 10 years ago.
I'd never been able to get it to heat up. To cut to the chase, I reflowed the solder in the pins and added a bit more for luck down each hole. The thing heated up when I tried it in the socket, which was a result.

Looking on Langrex, the same rectifiers now go for £250 :shock:
https://www.ebay.com/itm/5U4G-GEC-MOV-K ... 3f7ae44389

Crazy.

Mind you, it does sound nice. I can see the attraction, but......
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Paul Barker
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#335 Re: 6B4G - The Resurrection Shuffle

Post by Paul Barker »

I work daily in 'ull now. Heard about the bridge on Viking radio, fortunately I was in another area. Good man for sorting it for us.

:wink:
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#336 Re: 6B4G - The Resurrection Shuffle

Post by simon »

I wouldn't ordinarily go unless it's serious, but my inspectors were all on nights or leave so it was a bit of an emergency dash. It's about 10 years since I was last under that bridge checking the damage...

I probably shouldn't say too much on a public forum but it was quite an interesting afternoon. The police had to blue light me through the traffic as it was chocka. I hadn't even got out of the petrol station where they met me before someone cut me up to tailgate the police car. I lent on the horn to try to make him aware I needed to follow the police car and he turned around, gave me the finger and looked like he wanted to rip my head off. The bobby explained the situation through the window using the international language of gesture :-).

I'd always wondered what it was like to part two lines of queued or slow moving traffic, and it's a bit scary. It is when you're following a police car and the lines decide to close up behind it before you've got through...
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#337 Re: 6B4G - The Resurrection Shuffle

Post by ed »

I'd have waved if I'd known it was you...

wierdly, the first traffic car went through and the message in the back window was 'move left'. the second traffic car went through and the message was 'road closed'...The queue inched forward and when we got to the bridge the damage was in the left hand lane and the right hand lane was being waved through...go figure! neither message was correct, do you think there is room for improvement?
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#338 Re: 6B4G - The Resurrection Shuffle

Post by simon »

I'm sure Humberside Police would value your feedback :-).

I did type a reply but it's a conversation for Owston really.
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#339 Re: 6B4G - The Resurrection Shuffle

Post by IslandPink »

"Once you find out ... the Circumstances ; then you can go out"
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#340 Re: 6B4G - The Resurrection Shuffle

Post by Ant »

Naaah steve s has a shed full! Ten a penny I tells ya :D
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#341 Re: 6B4G - The Resurrection Shuffle

Post by steve s »

That's been for sale for an age...
Normal ones go for around the £150+ mark on eBay unless they are special
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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#342 Re: 6B4G - The Resurrection Shuffle

Post by Cressy Snr »

A bit more fine tuning of the sound has been going on over the Christmas period.
I took out the cheap, Vishay polypropylene coupling caps, connecting the input to the driver stage and replaced them with
Russian K75-10 green PIO jobbies. I got these off Phil, a very long time ago, now.

In this amp, the green grenades give the sound a particularly full-blooded presentation with vivid tonal colour saturation.
They are a bit dark up top, but the are wonderful sounding things despite that.
I got the best of both worlds by bypassing with 220pF, red, WIMA MKPs. These allowed the Russians to keep their saturated midrange but the treble extension was returned to the fold.

Image

Other people report mixed results with the Russian green caps, praising the addictive, seductive quality of the midrange tone, but bemoaning the darkness in the treble. This bypassing technique gives great results in the treble region.
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#343 Re: 6B4G - The Resurrection Shuffle

Post by Cressy Snr »

FINALLY got aroung to fitting bleeder resistors in the power supply.

A 22K, 12W Mills power resistor in the end of each leg of the power supply, drops 270V at 12 and a bit mA, dissipating 3 and a bit watts, so 22mA gets drawn through the choke regardless, when the amp is on.
They also discharge the caps to zero volts in one minute. We are down to 40V within a few seconds of switch off.
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#344 Re: 6B4G - The Resurrection Shuffle

Post by Cressy Snr »

Will put up the revised PSU described in the beginners thread tomorrow.
The choke is in the 0V rail.
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#345 Re: 6B4G - The Resurrection Shuffle

Post by Cressy Snr »

Revised power supply.
Image
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