Orange bass terror HT voltage

[mikeydee]

I bought an old OBT pre amp board from obbm to create a little pre amp module. I have it working fine with the input ht set to 240vdc giving a plate voltage of about 140 on v1a.

I would be keen to hear from any one that knows what the ht should actually be. And, if anyone has a schematic that would also be very welcome.

Mike

[Bigwan]

Your wish is my command! PM me your email.

[mikeydee]

Done

[mikeydee]

Just in case anyone was anxioustto know, it turns out the high voltage supply to the pre amp is 175v.

[Subthumper]

That would probably explain why they overdrive so easily. The less voltage the browner the sound. That's quite low compared to a lot of other amps using the same valve. Or is that the voltage on the actual plate of the valve as opposed to the HT supply?

[mikeydee]

Yes I was expecting something in the range of 150-250 volts.

The 175v is what is supplied to the HV connector on the input board. There are a couple of 10k dropper resistors one for V2 and a further one for V1 so the plate voltage on V1 is reduced a fair bit once biased up.

I'll post measurements if folks are interested.

See you are in Bristol too - so a local Hi to Subthumper.

[Subthumper]

A Bristol hello to you too. I don't have the otb schematic but I do have the ad200. I'm sure that runs at least 100volts plus,more than the terror. Would be interesting to compare the two and see if the otb is improved if run at a higher voltage.