9th Nov 2013, 8:15 am | #141 |
Tetrode
Join Date: Mar 2011
Location: St Austell, Cornwall, UK.
Posts: 53
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Re: Tuac Amplifier modules
As requested
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10th Nov 2013, 9:45 pm | #142 |
Octode
Join Date: Aug 2008
Location: Rayleigh near Southend-On-Sea, Essex, UK.
Posts: 1,883
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Re: Tuac Amplifier modules
Hi Chris,
Thanks for uploading the circuit for the TUAC amplifier. I figure this is an earlier circuit (circa 1973?) than the one I copied, which was made in 1979. I’ve had a quick look at the two and noticed the following: Later unit Parallel combination of the 2K7 & 5R6 resistors both in series with the 22uF capacitor in the inner DC feedback loop, CR network across the driver transformer primary (I’m wondering if this is in place of the parallel resistor capacitor in the main feedback loop in the earlier unit?) and DC coupling of the main feedback loop. And of course the plethora of feedback resistors! Early unit 3R9 in series with the bases of the output transistors, AC coupling of the main feedback loop, slightly different feedback arrangement with a potential divider and a 100pF capacitor across the 18K (?) feedback resistor. This is less the plethora of feedback resistors found on the later unit. Apart from the above they are more or less the same. Terry |