Astroid 60 PT ( HTS-8593 )

[joCCe]

Hi all

According to the info I have, this PT should have about 730V on the secondaries. I ordered one from Heyboer and they say the secondaries are 375-0-75-375, or 750V??

I'm not sure what to make of this. Have you guys checked the secondaries on the Heyboers you've used?

Thanks
Joakim

[LeftyStrat]

Hi all

According to the info I have, this PT should have about 730V on the secondaries. I ordered one from Heyboer and they say the secondaries are 375-0-75-375, or 750V??

I'm not sure what to make of this. Have you guys checked the secondaries on the Heyboers you've used?

Thanks
Joakim

375 should give about 530 unloaded.

[M Fowler]

Well 375v + 375v = 750v center tapped. Has a bias tap as well. All data I have states the 750v is correct value.

I have talked with Heyboer about these transformers a few times and they certainly know which transformers are needed for each application whether the K60 or K50 (K50 uses a different OT value is all).

Edit: I see what your talking about one voltage chart shows 728Vac and another shows 764Vac. I don't think I kept any records of my voltage might have to look at my past posts for that info as I remember going over my plate voltage and bias with bnwitt.

Mark

[joCCe]

Edit: I see what your talking about one voltage chart shows 728Vac and another shows 764Vac. I don't think I kept any records of my voltage might have to look at my past posts for that info as I remember going over my plate voltage and bias with bnwitt.

Mark

Yes, that's it. Sorry if my post was unclear.

I've only seen the PT scheme that says 728VAC on the secondaries, so I was surprised when the Heyboer spec showed a total of 750VAC.

Thanks
Joakim

[LeftyStrat]

Sorry I thought you were talking about something completely different.

[RJ Guitars]

I think it has something to do with the Heyboer practice of using "unloaded" ratings for their transformers. I talked with Phil at Heyboer about this tranny and he said they developed those values to attain the proper values listed for the intended amplifiers. I have them in stock and could get some measurements on one if anyone is really interested.

rj

[rhinson]

the correct value is 365-0-365 at idle (maybe 30 -40ma current draw on each tube) on the hv sec. you can add about 3 or 4 volts extra on the total for the unloaded ac. value---so call it 368-0-368. the wire for the winding will be rated at 250 - 300ma, so figure 27ga wire. essentially any higher voltage jtm45 type power trannie will get you there, unless you're anal about the dual primaries. there are several jtm45 type models out there. the heyboer numbers for the komets are ones i originally had them make back 6 or 7 yrs ago, and have been posted on this forum for about that long. several well known builders have been using them in their amps. heyboer is not the original komet trannie maker. and btw they rate them unloaded essentially because that's the way i ask them to rate them. i don't like the fully loaded rating detail unless they give you an unloaded spec as well. rh