833a Amp - World-Designs-Forum

pre65 · #1 29th January 2011, 11:34 AM

Work has started on this beast, slow progress (cos I'm a slow worker

) and the first pair uf GU-48 (833a) came damaged in transit. Not broken glass but fell apart internally.

Here's a picture of the first monoblock trolley with bits laid out to get the best layout.

[IMG]

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pre65 · #2 1st February 2011, 03:04 PM

Snail pace building continues.

I've managed to get one filament PSU up and running. With a 12V SM PSU and dropping resistors and smoothing caps I get 9.96V. Target was 10V so close enough ?

Richard · #3 1st February 2011, 03:41 PM

That's huge Philip, my amp sat ON a TV stand but wasn't part of it

err, is it a stereo TV stand or are there 2 of them....

pre65 · #4 1st February 2011, 03:50 PM

Quote:

Originally Posted by Richard

That's huge Philip, my amp sat ON a TV stand but wasn't part of it

err, is it a stereo TV stand or are there 2 of them....

No, there are two ! While clearing out the loft (to have it insulated) I found two identical trolleys.

Bear in mind these are just the output stages, there is a 300b (or PT15 or KT66) amp and power supply to go with them as well. And also the HUGE Hammond output transformers are offboard, so floor space could be a problem.

#5 1st February 2011, 10:37 PM

All I can say is WOW

BOONDI · #6 2nd February 2011, 01:23 AM

Quote:

Originally Posted by pre65

No, there are two ! While clearing out the loft (to have it insulated) I found two identical trolleys.

Bear in mind these are just the output stages, there is a 300b (or PT15 or KT66) amp and power supply to go with them as well. And also the HUGE Hammond output transformers are offboard, so floor space could be a problem.

Seems to me your just showing off now Philip.....:p

Superb......

pre65 · #7 2nd February 2011, 09:23 AM

Well , I started with 832a, so one up seemed a good thing to try.

Keeps me out of mischief.

Dave Cawley · #8 2nd February 2011, 10:40 AM

As admin on this site I must point out this project has the capacity to instantly kill and also to burn a house down, and easily both.

The proposed very long wires could easily set up a feedback oscillator with might be a big problem. The use of 1,500 volts at half an amp would instantly kill you.

But perhaps the most worrying is the 1,500 volt return through a SMPS which will simply not handle it and is likely to instantly catch on fire and put a destructive voltage through the mains affecting your own and adjacent properties.

Please feel free to talk about this on this forum, but it must be noted that the forum owners cannot approve or endorse any such home build. Further more this forum cannot be held liable for loss of life or property by ignoring this notice.

Sorry for the hard stuff....................

Regards

Dave

pre65 · #9 2nd February 2011, 03:55 PM

Hi Dave, you seem to be making several quite incorrect assumptions.

1500V ? where did that come from.

1500V through SMPS ? Oh yeah, how did you work that out ?

Very long wires ? Have you measured them ? How long is very long ?

If you want accurate details of my DIY electrocution/spontaneous combustion device just ask.

Any HT on any valve amp, DIY or proprietary can kill, that we all know, or should do.

colin.hepburn · #10 2nd February 2011, 05:39 PM

I think someone needs to do some research

I think we All know this hobby can kill ether by making a mistake or just being plan stupid it just doesn’t apply the valves ether It applies too Solid state Audio and any mains powered things you can stick you fingers in

Only 10 milli amperes (0.0001 amps) through the heart is enough to kill a human.