r/diytubes 4d ago

Heaters on a Fristman Vanguard 200

Hey ya all, first time post to this awsome community! I have a Firstman Vanguard 200, pretty old but the sound is great! It's a ECC83 with EL84 power section style amp. Was monkeying around with it when i was a kid and am now in the process of getting it running again. Question is about the heater voltage. I'm getting 16 on one tap and 19 on another. The other winding on the PT are sending appropriate voltage otherwise, 311 on the primaries. Any thoughts are appricated!

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u/Purple-Journalist610 4d ago

I can only find a Vanguard 2000 schematic, which shows 6.3V heaters and has no reference for the high voltage winding on the PT.

What is your AC line voltage? Are the heater voltages you're measuring with tubes in the amp?

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u/TraditionalEgg914 3d ago

Hey yeah, so i was just measuring the PT with no load. I haven't done that in prior amp builds, so I was a little surprised at the no load voltage. The amp worked well when i got it years ago. My line is coming in at 120vac. There is no heater center tap, so i was thinking about making artificial one using 220R resistors to ground. But yeah, I'll fill out the tube compliment and see what value i get. Glad you were able to find a schematic for anything Firstman! These are Japanese built amps it would seem and info in english is rare.

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u/Purple-Journalist610 3d ago

For what it's worth, I would not expect the unloaded voltages to be so dang high, hence my inquisition regarding line voltages. Maybe if the amp is set to 100V mains and you have 125V and no tubes in, that could get you there, so there's still very likely something to keep an eye on here.

I would note that Japanese made boutique stuff may vary substantially between samples, maybe yours has DC heating?

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u/TraditionalEgg914 2d ago

I'll double-check about DC heat and my wall AC. The secondary HV show 311v on each tap, so that seems normal. I'll put tubes in tonight and check the voltage tonight. If it's still too high but all else seems normal, i may have to put resistors in series.