Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: LooseChange on October 03, 2010, 05:47:42 pm

Title: Valco 6150 on the bench - need PT advice
Post by: LooseChange on October 03, 2010, 05:47:42 pm

Nice condition but the PT burned up.
I have no idea what the voltages are but my guess is lower than a Champ.
The PT is a stand up type and I'm looking for some alternatives.
Can you guess the secondary voltage requirement?

Looking for good value on this one.

Thanks!

Title: Re: Valco 6150 on the bench - need PT advice
Post by: mresistor on October 03, 2010, 06:05:51 pm

Magnetic Compenents says they have a replacement Valco, might be worth looking into.... or not...

http://www.classictone.net/#anchor_657 (http://www.classictone.net/#anchor_657)

Title: Re: Valco 6150 on the bench - need PT advice
Post by: DummyLoad on October 03, 2010, 06:29:57 pm

my guess would be 240-0-240 @50ma +/-.

hammond 270X probably would work.

Title: Re: Valco 6150 on the bench - need PT advice
Post by: LooseChange on October 03, 2010, 07:05:27 pm

You think the HT secondaries are around 240? With a 5Y3.
The only hint I get is the 330 ohm cathode resistor. Can you estimate the B+ with that?

Magnetic components shows they make that PT but no one sells it.

Thanks!

Title: Re: Valco 6150 on the bench - need PT advice
Post by: DummyLoad on October 03, 2010, 08:19:59 pm

without knowledge of the load resistance, it's just a guess. i assumed a 10k load.

Title: Re: Valco 6150 on the bench - need PT advice
Post by: stingray_65 on October 03, 2010, 08:37:34 pm

Hey LC!

I know Rick at Amp parts Direct will have any Mag Comp tranny drop shipped to you.

Harder to do through Triode electronics, but not impossible. Funny thing is Triode is just a few miles from Mag Comp, could take a bus there and back on your lunch break and still sneak in a dog and fries.

Rick is way down in FLA and does magic with them.

Ray

Title: Re: Valco 6150 on the bench - need PT advice
Post by: LooseChange on October 04, 2010, 05:09:32 am

Thanks Ray.

I would really like to know what the specs would be for this. I found a few PT's small enough to fit and may do the job.

Title: Re: Valco 6150 on the bench - need PT advice
Post by: stingray_65 on October 04, 2010, 05:56:57 am

Maybe give Mag Comps a call?
looks like they may have your info with some authority.

Title: Re: Valco 6150 on the bench - need PT advice
Post by: LooseChange on October 04, 2010, 06:44:43 am

I saw that... Why didn't they add the voltages? Isn't that what dictates the size?

Title: Re: Valco 6150 on the bench - need PT advice
Post by: eleventeen on October 04, 2010, 08:17:08 am

That's really kind of amazing to see that internal spec sheet. I'm surprised it doesn't list what the chief engineer had for breakfast!

Title: Re: Valco 6150 on the bench - need PT advice
Post by: Geezer on October 04, 2010, 08:58:04 am

Quote from: eleventeen on October 04, 2010, 08:17:08 am

That's really kind of amazing to see that internal spec sheet. I'm surprised it doesn't list what the chief engineer had for breakfast!

Yeah, everything except that and what LC really needs to know....the secondary voltages!  :embarrassed:

Title: Re: Valco 6150 on the bench - need PT advice
Post by: Boots Deville on October 04, 2010, 09:58:28 am

Hey LC, this one looks pretty darn close and shows a 270-0-270 HV winding with 290V on the plate.

http://www.el34world.com/charts/Schematics/Supro_LATE_50S_1x6V6_AMP.pdf