30 Volt 5 Amp Transformer?

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I found an Italian company what will sell me a
30V 5A Transformer.
120V 60Hz Primary.

They want about $140 US. It's a high quality transformer built for clean power for audio equipment. So, I'm tempted. But, I don't want to pay that much. I was hoping for around $75.

I cannot find anyone in the US that sells Transformers this large.

As many of you know, I'm building the Zen amplifier and it
calls for this transformer. So, I'm assuming it is available somewhere.

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Avel/Linberg in New England sells a torodial for around $60. See old Audio Electronics ads.
Plitron, but it's in Canada I beleive. Around the same prices. Both these guys have almost any size you'll need!

I got mine at Avel/Linberg- 25+25 @ 6 amps 300vac.

MCM Electronics has Hammond tramsformers, if you don't want torodials. Or, http://www.hammondmfg.com. I saw both types on their site.

Are you trying to build a larger version? I think the plans call for 25 + 25 @ 6 amps.

Q1 IRFP140 N channel Mosfet
min 50V, 10A, 125W
Q2 IRFP9240 P channel Mosfet
min 50V, 10A, 125W
Q3 MPSA92 NPN transistor
min 50V, 10mA, TO92
Z1 1N5239 9.1V 500mW 5%
digi-key # 1N5239BPH
P1 10k Ohm pot digi-key# 3386P-103-ND
BR1 25A 50V digi-key# GBPC12005
F1 5-6A fast blow 3AG type fuse
Transformer 24-25V AC
@ 5A secondaries
T1 Avel Lindberg # D4040 (2channels)
T1, T2 Toroid Corp #617.242 (1 for ea ch.)


"The power transformer should source about 25 volts AC at 6 amps or so for each channel. While the actual DC draw is exactly 2 amps per channel, the power factor created by charging the power supply capacitors results in transformer dissipation greater than suggested by the 2 amps. From Fig 5 you can see that the suggested power transformer has a secondary coil for each channel, however it is acceptable to drive both channels from a single secondary and diode bridge."

I just bought a toroid type 30V 7.5A from Hammond Mfg.

It was $50 plus shipping.

The supplier was Allied Electronics. They didn't sell the 30V 5A. They even had to back order the 7.5A.

So, that's the last of the parts I need.

The revisions are on the passlabs site. They are mostly concerning noise from the power supply and reducing the distortion a little.

I'll let you know how it sounds.

Hi Pixie,

I don't know if I'm late, but, why don't you try a local manufacturer to make your transformer?

I think you can design the transformer easily (there are many books about the matter in USA) and leave only the mechanical work to the manufacturer.

In this case, your specifications would be much better than comercial designs are (current densities, area, dissipation, shielding etc.).

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