Overdrive Special, Steel String Singer, Dumbleland, Odyssey, Winterland, etc. -
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Mr. dB
Posts: 261 Joined: Sat Jun 10, 2006 6:58 pm
Location: Little Rock, Arkansas
Post
by Mr. dB » Mon Apr 03, 2017 2:30 am
Bombacaototal wrote: ↑ Sun Apr 02, 2017 8:28 pm
Aaron wrote: ↑ Wed Mar 01, 2017 10:51 pm
I'm still hesitant with the LNFB V1b+V2a, actually it's V2+V3a. If V2 is a pentode, there isn't enough parts in the circuit to make it work.
Based on the comment from
Electron: You have the first tube right,but the feed back on the second tube is taken off the cathode of a third tube .
And after reading this:
http://www.valvewizard.co.uk/pentode.html
I am wondering if maybe the LNFB is not like attached in the SSS #002 style with the values from the handsketch (10M, .05uF)?
Pure guessing so take it with a pinch of salt
You've returned your feedback loop to ground?
If you meant to return it to the cathode, you can't do that either unless you remove the bypass cap.
Bombacaototal
Posts: 1673 Joined: Thu Oct 06, 2016 5:53 am
Post
by Bombacaototal » Mon Apr 03, 2017 7:06 am
Mr. dB wrote: ↑ Mon Apr 03, 2017 2:30 am
Bombacaototal wrote: ↑ Sun Apr 02, 2017 8:28 pm
Aaron wrote: ↑ Wed Mar 01, 2017 10:51 pm
I'm still hesitant with the LNFB V1b+V2a, actually it's V2+V3a. If V2 is a pentode, there isn't enough parts in the circuit to make it work.
Based on the comment from
Electron: You have the first tube right,but the feed back on the second tube is taken off the cathode of a third tube .
And after reading this:
http://www.valvewizard.co.uk/pentode.html
I am wondering if maybe the LNFB is not like attached in the SSS #002 style with the values from the handsketch (10M, .05uF)?
Pure guessing so take it with a pinch of salt
You've returned your feedback loop to ground?
If you meant to return it to the cathode, you can't do that either unless you remove the bypass cap.
I thought this was the approach taken on #002 (attached) between V1B and V2A
Just realised I am missing one resistor before the ground of the 1st cathode
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Mr. dB
Posts: 261 Joined: Sat Jun 10, 2006 6:58 pm
Location: Little Rock, Arkansas
Post
by Mr. dB » Mon Apr 03, 2017 6:08 pm
Bombacaototal wrote: ↑ Mon Apr 03, 2017 7:06 am
Just realised I am missing one resistor before the ground of the 1st cathode
Ah that makes all the difference.
Bombacaototal
Posts: 1673 Joined: Thu Oct 06, 2016 5:53 am
Post
by Bombacaototal » Mon Apr 03, 2017 7:22 pm
Mr. dB wrote: ↑ Mon Apr 03, 2017 6:08 pm
Bombacaototal wrote: ↑ Mon Apr 03, 2017 7:06 am
Just realised I am missing one resistor before the ground of the 1st cathode
Ah that makes all the difference.
Sorry about that
BAck to the task in hand, is this idea a possibility? Another could be cathode of V3b and plate load of V2, but not sure how that would work
Bombacaototal
Posts: 1673 Joined: Thu Oct 06, 2016 5:53 am
Post
by Bombacaototal » Wed Apr 05, 2017 7:31 pm
Another pic of this amp (right side)
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