RE: Touche', sort of...

Posted by cpotl (A) on February 16, 2015 at 08:50:13

In Reply to: RE: Touche', sort of... posted by Ralph on February 16, 2015 at 08:02:54:

I used an 8 ohm load impedance in my Spice simulation of the M-60.

Just to be absolutely sure I'm using the right magnitude for the bias currents for the output tubes, could you confirm that something like 60 mA or so per triode section is what you are using?

By the way, calculating the output impedance for the M-60 simulation in what I would regard as the "standard" way (putting an AC current source across the output terminals and calculating Z as voltage over current), I get results that vary between about 4 ohms and 9 ohms, depending upon what the output impedance of the signal source is. (This is reasonable, because the degree of feedback provided by the 2M ohm resistors from the output to the input stages depends on whether they just "see" the 100K ohm grid-to-ground resistors at the input, or whether they see lower impedances in the case that there is a low output impedance signal source connected to the input.) Anyway, the 4 ohm figure I get for the output impedance, corresponding to having a fairly high impedance signal source, seems to accord with the figure you quote for the M-60 on your website. I guess that gives some confidence the simulation is reasonably trustworthy.

Chris

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Follow Ups Full Thread

Topic - Aries Cerat...SE OTL from Cyrus!! - morricab 04:24:43 02/12/15 (28)

RE: Aries Cerat...SE OTL from Cyrus!! - coolhand 15:55:49 02/12/15 (0)

Thanks for the heads-up - Lew 07:55:14 02/12/15 (26)

RE: Thanks for the heads-up - cpotl 16:11:12 02/12/15 (25)

Touche', sort of... - Lew 07:15:53 02/13/15 (24)

RE: Touche', sort of... - morricab 12:29:39 02/14/15 (11)

RE: Touche', sort of... - Lew 20:55:03 02/16/15 (10)

RE: Touche', sort of... - morricab 01:50:00 02/19/15 (9)

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RE: "Until you compare them to equally good no feedback circuits I can imagine you don't hear the consequences.." - morricab 11:59:26 02/23/15 (1)

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RE: "Until you compare them to equally good no feedback circuits I can imagine you don't hear the consequences.." - Banat 11:17:30 02/23/15 (5)

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RE: Triode outputs on a Futterman... - Banat 15:43:32 02/23/15 (3)

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RE: Triode outputs on a Futterman... - Ralph 08:50:47 02/25/15 (0)

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RE: Touche', sort of... - cpotl 08:15:26 02/13/15 (11)

Re the 6C33C... - Lew 09:44:35 02/14/15 (3)

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RE: Touche', sort of... - Ralph 14:18:40 02/13/15 (6)

RE: Touche', sort of... - cpotl 16:08:45 02/14/15 (3)

RE: Touche', sort of... - Ralph 08:02:54 02/16/15 (2)

RE: Touche', sort of... - cpotl 08:50:13 02/16/15 (1)

RE: Touche', sort of... - Ralph 09:32:25 02/16/15 (0)

RE: Touche', sort of... - cpotl 15:18:19 02/13/15 (1)

RE: Touche', sort of... - Ralph 08:11:25 02/16/15 (0)

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RE: Touche', sort of... - cpotl 08:50:13 02/16/15 (1)

RE: Touche', sort of... - Ralph 09:32:25 02/16/15 (0)

RE: Touche', sort of...

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