Need project ideas to fit this chassis

[taj]

I have 2 old Bryston 4B amplifiers that I would like to retrofit with new amp circuits. (see drawing attached). Any ideas which existing DIY amp circuit projects might suit these chassis without too much hassle? The hardware is too useful to be sitting in my junk pile.

The chassis are 19" rackmount by 5.25" high. There are 4 heatsinks per channel each one currently holding 2 TO-3 output devices and a TO-220 device. (8 output devices per channel, 16 total in the chassis)

The existing circuit boards (shown in green) are about 4.5" wide mounted vertically and they use 2 daughter output boards. The blue one is an I/O and power board. The existing power supply provides approx. +/-72V rails.

I was thinking maybe a Leach amp, with additional output devices, but I don't know enough about electronics to modify that circuit without serious help from this forum. But any other ideas are welcome.



Thanks!

-- Todd

[Leolabs]

Seen that you are not know enough about electronics,it's kind of risk to deal with something with such a high power DIY stuff.Suggest that you buy a kitset rather than build by your own.

[Zero Cool]

those old brystons are worth at least $600 in working condition and at least 200-300 in non working condition!

PLEASE dont be hacking up gold like this. sell them, use the money to build your own. but please dont butcher the Brystons!



Zc

[taj]

Originally posted by Leolabs
Seen that you are not know enough about electronics,it's kind of risk to deal with something with such a high power DIY stuff.Suggest that you buy a kitset rather than build by your own.

I have built and even repaired plenty of amplifiers and know enough about it to stay out of trouble. It's circuit design that I don't know enough about yet, but I am learning. Kits don't interest me.

[taj]

Originally posted by Zero Cool
those old brystons are worth at least $600 in working condition and at least 200-300 in non working condition!

PLEASE dont be hacking up gold like this. sell them, use the money to build your own. but please dont butcher the Brystons!
Zc

If these amps were in any acceptable shape, I would completely agree with you. However, they are 25 years old, used at many thousands of concerts. They are completely beat up in every sense almost beyond recognition, and the circuit boards and output sections have been repaired so many times the traces are half replaced with jumpers. That's why my old company gave them to me free.

The only real remaining value is in their hardware to a DIY'er like myself.

So, enough with all the objections, lets hear some ideas.

..Todd

[TomWaits]

Originally posted by taj


I have built and even repaired plenty of amplifiers and know enough about it to stay out of trouble. It's circuit design that I don't know enough. Kits don't interest me.

If you proceed I'll buy your old PCB's from the Bryston's and then you'll have some extra cash for new stuff. Buying two new chassis like these in Canada would be in excess of $600 so your logic is not so far off after all. I don't think I'd do it just the same.

Show us some pics of the inside of your amps? They can't be that bad?

Cheers,

Shawn.

[taj]

Interesting thought...

If you (or anyone) can help with my project here, by modifying or designing an amp PCB to work with this form factor, I'll send you the boards free (from one amp.) Since I have two such chassis, there are two opportunities here.

..Todd

[john65b]

Drop a UCD400 or UCD700 in there. You can do it in a couple of hours. No Soldering either.

Trasformer is all you need, with the amp boards and power board.

Cake...and you will be VERY happy.

My 2 cents.

[TomWaits]

Originally posted by taj
Interesting thought...

If you (or anyone) can help with my project here, by modifying or designing an amp PCB to work with this form factor, I'll send you the boards free (from one amp.) Since I have two such chassis, there are two opportunities here.

..Todd

What's in there? How many Motorola TO3's mount on the heat sinks? Do you want to use TO3 devices on the new design? Are you going to buy new PCB's? Are you going to etch your own PCB's? The Bryston chassis is optimized for a certain set up. If you are confident to carry through with it then strip one block down and give us the run down. Anything could fit in there but not anything really.

Heck who needs a chassis if you use a UCD module? As john65b suggests? Don't those things suffice from a piece of aluminum foil 2x3cm?

Do you really want to tear down such coveted amplifiers? What is wrong with them? It's almost hard to take you serious. I'm not saying they are the best but what is soooo wrong with them that leads you to rip them to ribbons?

Cheers,

Shawn.

[FastEddy]

" ... I was thinking maybe a Leach amp, with additional output devices ..."

According to the old reviews, the amps were >> US$2000 when new. Are you sure you want to gut them, they had a "20-year warranty"? Example: http://www.soundstage.com/revequip/bryston_4b_st.htm

The existing 4B power supply could handle as many as four good modern mono block amplifier boards of >> 100 watts each ... just reconnect the 120/240 VAC transformer (or lock the Euro 240 volt switch, perminently) so that the rails are +/- 36 VDC (instead of +/- 72 VDC). ... Then I might suggest several aussieamplifiers.com modules like two of these : http://aussieamplifiers.com/NX400+.htm ... or four of these : http://aussieamplifiers.com/nx150.htm ... ( here is what I did : http://3dotaudio.com/ampics.html = simple as making a pie )

I might also suggest that you keep all the I/O connections and hardware or you will spend a lot of time shagging new parts.

Before you cut them up, you consider making some trades ... maybe Tom (Shawn) in Canada (above) has something you could use. (You are both in Canada, so shipping should be reasonable ... add an extra US$50 or so, each, to ship south to the states.) Heck, I'd take the worst one and offer something in trade ...