Dynaco ST70 - Page 2

planet10 · 25th May 2004, 09:15 PM

Quote:

Originally posted by SY
p10- all you need is a Jensen JT11-P1 on the input...

or get the balanced pre out the gate (have a significant portion of the kit already, and the rest is mostly paid for)

dave

Eli Duttman · 25th May 2004, 10:02 PM

Combination bias attempts to have "EVERYTHING". The unbypassed 100 Ohm cathode resistor provides: some of the grid bias needed, stabilization of the operating point, and reduced distortion due to degeneration. TANSTAFL does apply, as the O/P impedance is raised slightly.

fdegrove · 25th May 2004, 10:22 PM

Hi,

Quote:

p10- all you need is a Jensen JT11-P1 on the input...

Why the extra xformer?

Quote:

as the O/P impedance is raised slightly.

You can easily ignore it, the Boyle idea also provides for some extra safety to the output tubes in case the bias supply goes on the blink.

Needless to say...I like it.

SY · 25th May 2004, 10:28 PM

Quote:

Why the extra xformer?

Balance and galvanic isolation. Steve Eddy has brainwashed me.

cwteoh · 27th May 2004, 06:07 AM

I am really not very sure about the schematic. From my second schematic, any issue found? should I get started with it? Anyone can tell me how it sounds like?

25th May 2004, 10:02 PM	#12
Eli Duttman diyAudio Member Join Date: Apr 2004 Location: Plainsboro, NJ	Combination bias attempts to have "EVERYTHING". The unbypassed 100 Ohm cathode resistor provides: some of the grid bias needed, stabilization of the operating point, and reduced distortion due to degeneration. TANSTAFL does apply, as the O/P impedance is raised slightly. __________________ Eli D.

27th May 2004, 06:07 AM	#15
cwteoh diyAudio Member Join Date: Sep 2003 Location: Penang, Malaysia	I am really not very sure about the schematic. From my second schematic, any issue found? should I get started with it? Anyone can tell me how it sounds like? __________________ Regards, C.W. Teoh

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