Re: Emulating tube amp source Z w. solid-state - is series RL network enuff?

Hi, Freddy -

Besides signal path capacitor upgrades and a beefed up capacitor value at the output stage supply, it's stock - no changes to resistor values. The damping factor is somewhere between 8-16 across most of the audio band. What I found interesting here that is if I beefed the supply capacitor any more than that, the Stereo 70 particular dynamic character started diminishing, implying that supply droop plays a part in this amp's characteristic sound.

Your Eico 6BX7 amp sounds like a gem. I have read that the 6BL7/6BX7 share many characteristics of the 6SL7 type such as great linearity and low microphonics, only with much increased power capability.

As a matter of fact, I am using the 6BL7GTA as a fully DC coupled long tailed differential driver tube for my OTL design which uses 8 6AS7G's per channel as totem pole outputs. One half of the 6BL7 drives the upper 6AS7's as followers and the other half drives the lower 6AS7's as inverters with local feedback from the output to the 6BL7 plate resistor to bring the gain into equilibrium with the upper half of the pp output. Even running open loop, the gain matching is so good with this output arrangement that no assymetrical distortion is visible on an oscilloscope under load or open circuit, which implies very good linearity on the part of the 6BL7 since the plate to cathode voltage of the section driving the lower half of the output stage is biased to 170VDC lower plate voltage than the upper half.

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Follow Ups Full Thread

Topic - Emulating tube amp source Z w. solid-state - is series RL network enuff? - freddyi 12:27:11 11/12/01 (17)

Damping Factor, output resistance.... - Thorsten 16:17:14 11/12/01 (10)

Re: Damping Factor, output resistance.... - PÃ¤r 04:03:26 11/13/01 (3)

-ve impedance - Pete McK 17:18:45 11/13/01 (0)

Re: Damping Factor, output resistance.... - Tom Dawson 09:19:50 11/13/01 (1)

Tnx both :-) - PÃ¤r 00:10:51 11/14/01 (0)

Are you saying NS1000 drops well below 4 ohms, Thorsten? - geeber 19:37:45 11/12/01 (0)

Re: Damping Factor, output resistance.... - Tom Dawson 19:29:02 11/12/01 (0)

Re: Damping Factor, output resistance.... - Tom Dawson 18:52:00 11/12/01 (2)

Nominal Load and Reality - Thorsten 03:35:12 11/13/01 (1)

Re: Nominal Load and Reality - Tom Dawson 08:41:03 11/13/01 (0)

Re: Damping Factor, output resistance.... - freddyi 16:57:14 11/12/01 (0)

Re: Emulating tube amp source Z w. solid-state - is series RL network enuff? - Tom Dawson 12:31:15 11/12/01 (5)

Re: Emulating tube amp source Z w. solid-state - is series RL network enuff? - freddyi 12:40:46 11/12/01 (4)

Re: Emulating tube amp source Z w. solid-state - is series RL network enuff? - Tom Dawson 11/12/0113:32:05 11/12/01 (3)

Re: Emulating tube amp source Z w. solid-state - is series RL network enuff? - freddyi 14:41:27 11/12/01 (1)

Re: Emulating tube amp source Z w. solid-state - is series RL network enuff? - Tom Dawson 15:29:48 11/12/01 (0)

Re: Emulating tube amp source Z w. solid-state - is series RL network enuff? - Tom Dawson 13:40:55 11/12/01 (0)

Follow Ups

Re: Emulating tube amp source Z w. solid-state - is series RL network enuff? - Tom Dawson 11/12/0113:32:05 11/12/01 (3)

Re: Emulating tube amp source Z w. solid-state - is series RL network enuff? - freddyi 14:41:27 11/12/01 (1)

Re: Emulating tube amp source Z w. solid-state - is series RL network enuff? - Tom Dawson 15:29:48 11/12/01 (0)

Re: Emulating tube amp source Z w. solid-state - is series RL network enuff? - Tom Dawson 13:40:55 11/12/01 (0)

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