Search found 13228 matches

by martin manning
Tue May 14, 2024 11:46 am
Forum: Technical Discussion
Topic: Illinois brand capacitors still bad?
Replies: 16
Views: 757

Re: Illinois brand capacitors still bad?

Stevem wrote: Tue May 14, 2024 11:20 am Thanks for this test out and post, and yes that’s over a 10% different which is a lot!
My math says over 1000% in ESR. A current data sheet from Mouser indicates IC is part of CDE, and the max ESR for 10uF 160V axial at 120 Hz is 33.157 ohms.
by martin manning
Tue May 14, 2024 11:26 am
Forum: Technical Discussion
Topic: Does a 'bright cap' really boost highs?
Replies: 21
Views: 4974

Re: Does a 'bright cap' really boost highs?

Correct. The cap is a bypass around the upper part of the resistive divider.
by martin manning
Tue May 14, 2024 11:16 am
Forum: Technical Discussion
Topic: Does a 'bright cap' really boost highs?
Replies: 21
Views: 4974

Re: Does a 'bright cap' really boost highs?

I finally got a load of caps to try in my 5F1 based amp. Quick question: Do I put the bright cap between lugs 1 and 2 of the Volume pot, or between lugs 2 and 3? I've seen it mentioned both ways. Or doesn't it matter? Might depend on how you number the lugs. If lug 3 is the input, lug 2 is the wipe...
by martin manning
Tue May 14, 2024 11:13 am
Forum: Dumble Discussion
Topic: ODS 102 with 2x KT88s and built-in Dumbleator
Replies: 30
Views: 768

Re: ODS 102 with 2x KT88s and built-in Dumbleator

So, I'm just looking at the FET circuit and the Relay power supply. If I use the Triad F-216X 12VAC supply, it looks like I use a FWB rectifier. I need a TO220 Regulator? Any recommendations? It just needs to regulate that 12VDC? LM7812 regulator as shown on the D schematics will be fine. Looking a...
by martin manning
Mon May 13, 2024 6:25 pm
Forum: Dumble Discussion
Topic: ODS 102 with 2x KT88s and built-in Dumbleator
Replies: 30
Views: 768

Re: ODS 102 with 2x KT88s and built-in Dumbleator

Am I seeing right that I may be able to take my heater supply and use it to feed the power for the relay switching? Or is that generally more trouble than using one of these 12V transformers? I think it's simpler to use a separate transformer for the relays. You can use 12VAC and a bridge, or 6VAC ...
by martin manning
Mon May 13, 2024 4:47 pm
Forum: Dumble Discussion
Topic: ODS 102 with 2x KT88s and built-in Dumbleator
Replies: 30
Views: 768

Re: ODS 102 with 2x KT88s and built-in Dumbleator

... and trying to figure out what transformer works well for the relay power... Raoul Duke posted a data sheet for this small Triad for relay power using a FWB: https://www.mouser.com/ProductDetail/Triad-Magnetics/F-216X?qs=b1anAsPanWyvCrSmsu4ZQw%3D%3D This Hammond is also a possibility for FWB: ht...
by martin manning
Mon May 13, 2024 4:16 pm
Forum: Dumble Discussion
Topic: ODS 102 with 2x KT88s and built-in Dumbleator
Replies: 30
Views: 768

Re: ODS 102 with 2x KT88s and built-in Dumbleator

bcmatt wrote: Mon May 13, 2024 4:12 pmRight now I'm looking for that FET level knob mod with relay switching that Martin had drawn somewhere... and trying to figure out what transformer works well for the relay power...
There's info on these in the ODS boards .pdf here https://ampgarage.com/forum/viewtopic.php?f=5&t=29630
by martin manning
Sun May 12, 2024 8:46 pm
Forum: Dumble Discussion
Topic: 2nd Gen Build
Replies: 56
Views: 2562

Re: 2nd Gen Build

I did a bit of that and noticed it cleaned up well. If I can live with it that way and not have to alter the circuit that would be ideal. If not, the dual masters is a good plan. I never run two cabs anyways. The only bit of the circuit you would need to modify is between the OD2 coupling cap and O...
by martin manning
Sun May 12, 2024 2:01 pm
Forum: Technical Discussion
Topic: Hypothetical Amp Discussion
Replies: 9
Views: 359

Re: Hypothetical Amp Discussion

I already have something like this set up on an HX Stomp on my board at the moment, and it does sound great, but we started laughing at the idea of having both loops being tube-driven... And joked that we might as well throw in a tube-driven reverb tank in there too. That's a lot of tubes! 4 preamp...
by martin manning
Sat May 11, 2024 10:05 pm
Forum: Dumble Discussion
Topic: 2nd Gen Build
Replies: 56
Views: 2562

Re: 2nd Gen Build

Yes try changing the bias point. The gain should rise sharply at some point and then level off.
by martin manning
Sat May 11, 2024 3:01 pm
Forum: Dumble Discussion
Topic: 2nd Gen Build
Replies: 56
Views: 2562

Re: 2nd Gen Build

dbharris wrote: Sat May 11, 2024 2:50 pm New FET biased up easy. I set it for just under 3 for the Vdd/Vd ratio. It sounds good, but the volume is lower than the normal channel even with the FET trimmer wide open. I may bring the ratio closer to 2.5 and see if that helps.
What are the voltages at the top and bottom of the drain resistor?
by martin manning
Sat May 11, 2024 1:08 pm
Forum: FAQs
Topic: Tube amp grounding article/info/links
Replies: 26
Views: 80535

Re: Tube amp grounding article/info/links

Thanks Dai.

Moderators, maybe this thread should be moved to the new FAQ area?
by martin manning
Sat May 11, 2024 1:00 pm
Forum: Dumble Discussion
Topic: Robben Ford & His Dumble Overdrive Special
Replies: 15
Views: 507

Re: Robben Ford & His Dumble Overdrive Special

To be fair, the Robben part of the video was a fraction of the overall time. He's talked about his Dumble amps and his introduction to and friendship with HAD many times before, but there always seems to be something new. I agree hearing different players and different guitars was really valuable, a...
by martin manning
Sat May 11, 2024 12:25 pm
Forum: Dumble Discussion
Topic: 2nd Gen Build
Replies: 56
Views: 2562

Re: 2nd Gen Build

If that is just heater glow you are seeing through the hole in the tube base I wouldn't worry about it. Are you seeing that through the gap between the index pin and the socket? Might the odor be transformer varnish?
by martin manning
Fri May 10, 2024 10:37 pm
Forum: Dumble Discussion
Topic: The Much Anticipated (?) Bluesmaster Build Thread
Replies: 42
Views: 1461

Re: The Much Anticipated (?) Bluesmaster Build Thread

I was trying to come up with a rationale, but in the end at 120V the current limit will be the same, Bulb Wattage/120