Need to replace the transformer in this amplifier

Kramerguy · 18th December 2008, 07:55 PM

I have the schematics but I am having difficulty in finding the specs on this transformer. I was hopping one of you gents could lend a fellow a hand. I will get the chassis measurement tonight and post those up as well but I was hopping for insight into the electrical specs of such and animla as this.

The Amplifier is a Randall B2000 head for bass amplification. I will also attach the Preamp circuts as well in case anyone here is bored.

Kramerguy · 18th December 2008, 10:34 PM

Did not realize this was single attachment limited. Here is the power amp section. Yes it is Ok to post these shcematics I checked with Randall Amplfiers and they no intention of building this amplifier again.

jaycee · 18th December 2008, 11:46 PM

Looks like they used a 32-0-32 (64VCT) transformer. As for what VA rating, I can't tell without an indication of the amp circuit (the power amp schematic didn't attach).

How many watts output is the amp?

lineup · 18th December 2008, 11:52 PM

an old Randall

Kramerguy · 19th December 2008, 01:29 AM

I did attach it in the second posting if not I will do it again.

It is a BiAmp design 140 watts on the high end "4 mj15003" and 375 " idicated as 4 but actually 8 Mj15025" at a paltry 8 ohms. I was told when it was new that is was 2 ohm capable and It has proven it self able to do so. I have also run it down to 4 most of its life never a problem.

I know the rail voltage is fiarly high so it would be assumable that they designed it with lower Impedences and such in mind.

Any help you can offer would be fantastic.

Quote:

Looks like they used a 32-0-32 (64VCT) transformer. As for what VA rating, I can't tell without an indication of the amp circuit (the power amp schematic didn't attach).

Kramerguy · 19th December 2008, 01:29 AM

Crap here it is.

anatech · 19th December 2008, 01:33 AM

Hi Kramerguy,
Jaycee has nailed the voltage right on.

For current, just look at the breaker rating and buy a bit larger for headroom. Also, measure the core size and make sure your replacement is at least that big, but still fits. Drilling a couple mounting holes in the chassis may be required.

Still don't see your amp section. What for file size warnings when you attempt to attach a file.

-Chris

Kramerguy · 19th December 2008, 03:52 AM

any idea why I can only insert one attachment in this thread ?Jaycee if you would PM me your email or post up your email addy I will gladly email all the schematics to you.

anatech · 19th December 2008, 08:24 PM

Hi Kramerguy,

Quote:

any idea why I can only insert one attachment in this thread ?

Yes, I do .....

You are allowed one attachment per post. You can have multiple links to images in each post.

If you can not attach a schematic, it is too large to be accepted. You didn't see the error message. The maximum size is given, I can not remember off hand. So, if you reduce the file size, you can attach it.

If you don't mind, could you also forward the schematic to me as well? Send it to bhomester at gmail dot com. If I post my straight email address, spam bots can pick it up. Therefore, the email address is presented in a non-standard format.

-Chris

Kramerguy · 20th December 2008, 03:19 AM

Just sent it to ya.

18th December 2008, 11:52 PM	#4
lineup diyAudio Member Join Date: Dec 2005 Location: the north	an old Randall __________________ lineup

19th December 2008, 01:33 AM	#7
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hi Kramerguy, Jaycee has nailed the voltage right on. For current, just look at the breaker rating and buy a bit larger for headroom. Also, measure the core size and make sure your replacement is at least that big, but still fits. Drilling a couple mounting holes in the chassis may be required. Still don't see your amp section. What for file size warnings when you attempt to attach a file. -Chris __________________ "Just because you can, doesn't mean you should" © my Wife

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18th December 2008, 10:34 PM	#2
Kramerguy diyAudio Member Join Date: Dec 2008	Did not realize this was single attachment limited. Here is the power amp section. Yes it is Ok to post these shcematics I checked with Randall Amplfiers and they no intention of building this amplifier again.

18th December 2008, 11:46 PM	#3
jaycee diyAudio Member Join Date: Apr 2004 Location: Norwich, UK	Looks like they used a 32-0-32 (64VCT) transformer. As for what VA rating, I can't tell without an indication of the amp circuit (the power amp schematic didn't attach). How many watts output is the amp?

19th December 2008, 01:29 AM	#6
Kramerguy diyAudio Member Join Date: Dec 2008	Crap here it is.

19th December 2008, 03:52 AM	#8
Kramerguy diyAudio Member Join Date: Dec 2008	any idea why I can only insert one attachment in this thread ?Jaycee if you would PM me your email or post up your email addy I will gladly email all the schematics to you.

20th December 2008, 03:19 AM	#10
Kramerguy diyAudio Member Join Date: Dec 2008	Just sent it to ya.

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