Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Colas LeGrippa on June 22, 2012, 05:00:31 pm

Title: POWER TRANSFORMER transforms too much.
Post by: Colas LeGrippa on June 22, 2012, 05:00:31 pm

Hi,
I have found this huge transformer in a TONE GENERATOR , 20 tubes or so.  I was wondering why my meter was beeping btwen two leads of the HV, with no reading. Its max is 700V AC, 1000VDC.

From one side of the HV to the center tap is 550V, so I get 1100 V !!!!

What can I build with that beast ? An electric chair ?

Title: Re: POWER TRANSFORMER transforms too much.
Post by: John on June 22, 2012, 05:07:31 pm

Sell it for scrap, use the money to buy what you need.  :icon_biggrin:

Title: Re: POWER TRANSFORMER transforms too much.
Post by: sluckey on June 22, 2012, 06:50:24 pm

You can build one hell of a strobe light!

Title: Re: POWER TRANSFORMER transforms too much.
Post by: DummyLoad on June 22, 2012, 09:04:46 pm

Tesla coil?

Title: Re: POWER TRANSFORMER transforms too much.
Post by: terminalgs on June 23, 2012, 11:03:57 am

use it in a 20 tube tone generator.

Title: Re: POWER TRANSFORMER transforms too much.
Post by: Colas LeGrippa on June 23, 2012, 04:58:59 pm

yeah, back to where it belongs, with EXACT SPECS, genius you are !

Title: Re: POWER TRANSFORMER transforms too much.
Post by: Willabe on June 23, 2012, 05:19:09 pm

Why would you want to fool with a PT that puts out that much voltage?

I would leave it be.


     
                              Brad     :icon_biggrin:

Title: Re: POWER TRANSFORMER transforms too much.
Post by: bigsbybender on June 23, 2012, 11:56:41 pm

Use it in a "Choke-Input" Circuit.  That will drop the HT secondary voltage down to a usable B+ and you can use small value capacitors.... the only problem is caps are much cheaper than the choke needed to supply a full amp.....



j.

Title: Re: POWER TRANSFORMER transforms too much.
Post by: kagliostro on June 24, 2012, 06:45:45 am

550v * 1.4 = 770v with SS rectify, and using a Tube Rectifier the voltage will be lower

a PP of 807 is fine with 740v DC

see the Geloso G.273a

(http://www.chambonino.com/geloso/gelwire2b.jpg)

or you can experiment with GU50 tubes

look to page 9 of the EL152 tube datasheet (same specs)

(you can use less than 6 x GU50 tubes if you don't need very much power)

the photo refers to a GU50 Bass Amp



K