Bias voltage mod
Am building a hiwatt DR103 clone 90% complete but am looking getting a transformer built with 70v bias tap. Stock is 50v but hiwatt always run hot(not enough bias voltage) wondering if this would work. And what I should change the bias resistors to. Here is the bias circuit I'm looking at using for a basis the Dr103 with one pot. Thanks people hope you can help.
Am building a hiwatt DR103 clone 90% complete but am looking getting a transformer built with 70v bias tap. Stock is 50v but hiwatt always run hot(not enough bias voltage) wondering if this would work. And what I should change the bias resistors to. Here is the bias circuit I'm looking at using for a basis the Dr103 with one pot. Thanks people hope you can help.
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Bias voltage mod hiwatt
Am 90% complete with my hiwatt DR103 (4xel34) clone but want to do improve the anemic bias circuit. Haven't purchased a PT yet but am looking at betting a custom toroidal build with a 70v bias tap as the stock 50v is not enough they run hot usually around 38v. There is a mid circuit with one pot I was going to use. Need to know if a 70v tap will work if so what value should my resistors be. Thanks in advance.
Am 90% complete with my hiwatt DR103 (4xel34) clone but want to do improve the anemic bias circuit. Haven't purchased a PT yet but am looking at betting a custom toroidal build with a 70v bias tap as the stock 50v is not enough they run hot usually around 38v. There is a mid circuit with one pot I was going to use. Need to know if a 70v tap will work if so what value should my resistors be. Thanks in advance.
Attachments
Am 90% complete with my hiwatt DR103 (4xel34) clone but want to do improve the anemic bias circuit. Haven't purchased a PT yet but am looking at betting a custom toroidal build with a 70v bias tap as the stock 50v is not enough they run hot usually around 38v. There is a mid circuit with one pot I was going to use. Need to know if a 70v tap will work if so what value should my resistors be. Thanks in advance.
The current of a bias ciruit is very low. Therefore simple voltage doubler works fine with original power transformer.
You do not need to have a custom transformer just for bias.
The current of a bias ciruit is very low. Therefore simple voltage doubler works fine with original power transformer.
You do not need to have a custom transformer just for bias.
For the cost of shipping a mercury magnetics(120v primary only I believe) or Hammond or partridge clone I can have a toroidal built to my spec cheaper . This is why I was looking at this route . Or should I just get one built with 50v and use the doubler circuit?
3rd thread merged.
Brian please read the rules before posting again.
Apologies didn't think the first one posted so I tried again didn't realise a moderator had to confirm it.
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