Yes. You wire the pot as a variable resistor, and when the relay contacts are open it becomes the resistance to ground. If the trimmer is on the bus then there are two ground paths.Raoul Duke wrote: ↑Thu Apr 25, 2024 9:10 pm So put the trimmer connecting Com1 and NC1 - one side and wiper?
Search found 13203 matches
- Thu Apr 25, 2024 9:26 pm
- Forum: Dumble Discussion
- Topic: Bluesmaster HRM question:
- Replies: 90
- Views: 3339
Re: Bluesmaster HRM question:
- Thu Apr 25, 2024 8:50 pm
- Forum: Dumble Discussion
- Topic: Bluesmaster HRM question:
- Replies: 90
- Views: 3339
Re: Bluesmaster HRM question:
The biggest mistake I made when I first started building these amps however many years ago was to try to outwit Dumble with "tweaks" instead of trying to understand his original design intention. It's an urge that I have difficulty with to this day.....but I am working hard not to succumb! To concl...
- Thu Apr 25, 2024 1:00 pm
- Forum: Dumble Discussion
- Topic: Bluesmaster HRM question:
- Replies: 90
- Views: 3339
Re: Bluesmaster HRM question:
Yes! Thanks Erwin. Clever way to add that feature.
- Thu Apr 25, 2024 12:51 pm
- Forum: Garage Talk
- Topic: Stirs Neural pot
- Replies: 34
- Views: 1462
Re: Stirs Neural pot
This is one of the laws of thermodynamics.
- Thu Apr 25, 2024 12:13 pm
- Forum: Dumble Discussion
- Topic: Bonamassa new amp day
- Replies: 31
- Views: 1432
- Thu Apr 25, 2024 11:39 am
- Forum: Dumble Discussion
- Topic: Dumble ODS 102 build
- Replies: 15
- Views: 544
Re: Dumble ODS 102 build
Sometimes the difference is subtle, so I prefer using a DMM or scope to get a quantitative measurement.Guitarman18 wrote: ↑Wed Apr 24, 2024 6:10 pm This is a really simple and effective way to find the outer foil of your caps.
- Thu Apr 25, 2024 11:10 am
- Forum: Technical Discussion
- Topic: Blackvibe 6L6 Strange behavior on tone pots
- Replies: 17
- Views: 704
Re: Blackvibe 6L6 Strange behavior on tone pots
Thanks for the update. Makes sense.retodellatorre wrote: ↑Thu Apr 25, 2024 8:07 am So i changed the middle pot to a A 10K and removed the 6.8k to ground (just ground)... ... So i replaced the 0.047uf with a 0.022uf - and there we go.
- Thu Apr 25, 2024 10:52 am
- Forum: Dumble Discussion
- Topic: Bluesmaster HRM question:
- Replies: 90
- Views: 3339
Re: Bluesmaster HRM question:
Did Dumble actually do this or is it just another TAG tweak? Excuse me, just another TAG tweak? ;^) I seem to recall seeing a picture of this. It may have been in a HAD amp or maybe it was a mod by one of the commercial D clone builders. Does this mean the full 22M has a negative effect or that it’...
- Wed Apr 24, 2024 5:54 pm
- Forum: Technical Discussion
- Topic: Tone Stack Bypass RAW control
- Replies: 4
- Views: 304
Re: Tone Stack Bypass RAW control
Yes, it's a pot. The switch doesn't remove it from the circuit, just makes it go to the full 1Meg while preserving the setting. Alternatively, a switch in series with the pot could be used to open the bypass circuit and completely remove it, but it would be a good idea to put a large resistor across...
- Wed Apr 24, 2024 12:49 pm
- Forum: Dumble Discussion
- Topic: Bluesmaster HRM question:
- Replies: 90
- Views: 3339
Re: Bluesmaster HRM question:
As far as the lift resistance goes - 22M and 72k seem pretty far apart. What’s the best way to figure out where to start that experimentation? Higher value lifts more of the stack? 22M is the full lift, same as open circuit for all practical purposes. I've seen various values for the partial lift, ...
- Wed Apr 24, 2024 12:23 pm
- Forum: Dumble Discussion
- Topic: Bonamassa new amp day
- Replies: 31
- Views: 1432
Re: Bonamassa new amp day
He collects, shares his purchases and sells probably for a profit. His money and no-one suffers any damages AFAIK. And by the way, where would the amp otherwise go? A collector who puts it in a safe or at least doesn't show it to the world? What would we benefit from that? No harm except driving pr...
- Wed Apr 24, 2024 11:23 am
- Forum: Technical Discussion
- Topic: Tone Stack Bypass RAW control
- Replies: 4
- Views: 304
Re: Tone Stack Bypass RAW control
I believe he means to bypass it like this. I added the cap to block DC, and the bypass switch to get the full 1 Meg for "normal" mode from any partial-bypass setting. There will still be some effect from the tone controls with this bypass technique.
- Wed Apr 24, 2024 12:15 am
- Forum: Dumble Discussion
- Topic: Bluesmaster HRM question:
- Replies: 90
- Views: 3339
Re: Bluesmaster HRM question:
Did I have the connections correct? That’s where I got crossed-up. So I could follow mdroberts’ schematic and it would work the way most/many prefer? You understood the layout connections correctly. They are also shown in my ODS Eyelet Board .pdf. You can use MDRoberts scheme, but you might prefer ...
- Tue Apr 23, 2024 11:32 pm
- Forum: Dumble Discussion
- Topic: Bluesmaster HRM question:
- Replies: 90
- Views: 3339
Re: Bluesmaster HRM question:
Trying to work out the 22M “jumpers” on the mid- boost relay board in the layout. It looks like Com1 to NC1, Com2 to NC2 - but it’s hard to be sure - so I looked at the bm_clone schematic and it looks like NO1 to NC1 (with a 72k?) and NO2 to NC2 with the 22M value. I understand that schematic has m...
- Tue Apr 23, 2024 1:37 pm
- Forum: Dumble Discussion
- Topic: Dumble ODS 102 build
- Replies: 15
- Views: 544
Re: Dumble ODS 102 build
I have also made a huge error of not testing the orientation of any of my Orange Drop Caps so I am trying to buy a second hand Oscilliscope from someone on FB Marketplace (Havent gone to pick it up yet) You can do that with a multimeter. See here: https://ampgarage.com/forum/viewtopic.php?p=417375#...