Ampex 620 PT specs? – (need a euro replacement)

[Schmilsson]

I recently bought me an Ampex 620 to satisfy my living room mono hifi needs. It's of course 117v so I need a replacement transformer (unless I can find someone local to rewind the primary). Does anyone have the spec of the secondary? Or perhaps could figure it out by looking at the schem.

http://audiophool.com/Schem_A/Ampex_620-3.gif

Thanks!

 

[moamps]

Power transformer,
Part number: G.T.C. B-9402
Primary:
120 volts, 5.8 ohm winding dc resistance
Secondaries:
720 volt center tap @ .150 mA, 348 ohm dc resistance
6.3 volt center tap @ 4 A, 98 ohm dc resistance
6.3 volt @ 2 A, 150 dc resistance
Fabric insulation on wires
Dimensions:
2-5/8" lamination width x 3-1/4" depth x 3-1/8" height Bolt pattern center to center: 2" on the width side x 2-3/8" depth side

 

[PRR]

Fender DeLuxe replacement transformer gets you 9/10 there.

Woof, € 110,00!!

Fender used a 5V rectifier, Ampeg used a 6V rectifier. Me, I'd rip the bottle and use two 1N4007 rects with 200r 10W in series with each (to approximate the drop of a bottle rectifier). Less heat, longer life.

You could convert to 5Y3 rectifier (good enough for DeLuxe) but the socket is different (and much bigger). You would think there would be a 5V mini rect but all I find are Octal.

Have you considered a simple 230V:115V "travelers transformer"?

Also note that the Ampeg PT *may* have been designed for 60Hz. 50Hz operation of small (this is not large by some standards) transformers risks over-flux, saturation, quick heating, and smoke escape. Certainly do not run it on 125+V 50Hz, aim for 110V or even 105V. (105V wall voltage was not that uncommon when Ampeg made this.)

 

[Schmilsson]

Power transformer,
Part number: G.T.C. B-9402
Primary:
120 volts, 5.8 ohm winding dc resistance
Secondaries:
720 volt center tap @ .150 mA, 348 ohm dc resistance
6.3 volt center tap @ 4 A, 98 ohm dc resistance
6.3 volt @ 2 A, 150 dc resistance
Fabric insulation on wires
Dimensions:
2-5/8" lamination width x 3-1/4" depth x 3-1/8" height Bolt pattern center to center: 2" on the width side x 2-3/8" depth side

Sorry, could you be more specific please?
Thanks a bunch!

 

[Schmilsson]

Fender DeLuxe replacement transformer gets you 9/10 there.

Woof, € 110,00!!

Woof indeed! Here's to hoping edcor/hammond/whoever has something cheaper.

Fender used a 5V rectifier, Ampeg used a 6V rectifier. Me, I'd rip the bottle and use two 1N4007 rects with 200r 10W in series with each (to approximate the drop of a bottle rectifier). Less heat, longer life.

You could convert to 5Y3 rectifier (good enough for DeLuxe) but the socket is different (and much bigger). You would think there would be a 5V mini rect but all I find are Octal.

Ampex, not Ampeg, but still 6V I suppose?

Have you considered a simple 230V:115V "travelers transformer"?

This would be ideal since I'd like to keep it stock. I've looked into it but got the impression they wouldn't cut it for a tube amp, and those who did were more expensive than a replacement trafo anyway, but perhaps I'm mistaken?

Also note that the Ampeg PT *may* have been designed for 60Hz. 50Hz operation of small (this is not large by some standards) transformers risks over-flux, saturation, quick heating, and smoke escape. Certainly do not run it on 125+V 50Hz, aim for 110V or even 105V. (105V wall voltage was not that uncommon when Ampeg made this.)

Are you talking the output of a travelers transformer here?

 

[moamps]

... so I need a replacement transformer (unless I can find someone local to rewind the primary).....

This one looks ideal for your needs.

http://www.tube-town.net/ttstore/Transformer/Power-Transformer/Soldano/TT-Slo50-Soldano-SLO-50-Watt-Powertransformer::5838.html

 

[Audio1Man]

You should buy a step down power transformer rated for about 100 watts.  220/240vac input and 120 volts output.
Duke

 

[Schmilsson]

Thanks for all the suggestions. I didn't receive the unit 'til yesterday and ended up getting a 100W step down adapter/transformer 230 to 110v today. Seem to work just fine and wasn't too bulky nor expensive (30€).

 

[natrecstudio]

Does anyone possibly have an original to sell, or could suggest a sub for a US user?
I also have a 601 I don't care about.... might that have the same PT?
THANKS!!

 

[GabrieleP]

I recently bought me an Ampex 620 to satisfy my living room mono hifi needs. It's of course 117v so I need a replacement transformer (unless I can find someone local to rewind the primary). Does anyone have the spec of the secondary? Or perhaps could figure it out by looking at the schem.

http://audiophool.com/Schem_A/Ampex_620-3.gif
Thanks!

I had a local transformers builder wind one for my 620 in Europe. If he's good, he'll know what to do. Mine did.