> "Ian Thompson-Bell" <nospam@[EMAIL PROTECTED]
> wrote in message
> news:frtjf7$2cnt$1@[EMAIL PROTECTED]
>> Iain Churches wrote:
>>>
>>> Stability is a problem that brings many a DIY project to
>>> a shuddering halt. The builder switches the amp on, and
>>> it oscillates wildly. He switches it off, checks all the
>>> connections. Someone advises him to make sure that
>>> the feedback polarity is correct.After that, he is stuck.
>>> That may be part pf the reason why SET with ZNFB
>>> is so popular with homebrew builders:-)
>>>
>>
>> Wow, that takes me back to the very first tube amp I built in about
1963.
>> It was an SET design WITH global NFB. IIRC it used a 6J7 followed by a
>> 6V6. I was in my early teens and my constructional abilities were quite
>> poor. The thing hooted like mad. A more knowledgeable neighbour came
and
>> helped me and basically told me to rewire it 'properly'. This I did and
>> it
>> performed well. The design came from Practial Wirless. Oh, happy days.
>>
Happy days, indeed, when one call call in a neighbour to help
with a tube project:-)
Iain
