thanks for the suggestions.
I remember seeing, I don't know where, some photos describing the operation of opening the pot, cutting the track and resoldering the terminal (1 if I'm not wrong) ..... obviously when I reading this article I did not need to change the resistance of the pots and so I did not take note and / or save the article.
Buying a quantity of pot hoping that the tolerance is 40% seems like trying my luck
I was under the impression it was known dumble did this as do many builders... I'd just never tried it. Why does it reduce the life of the pot? I know if you scrape too much you definitely can damage it enough to reduce continuity. What often seemed odd to me was why removing places current can 'go' makes it have more resistance... but that's probably something that requires a PhD to understand That's why it always confused me.
From my personnal experience you can use an Xacto knife and carefully remove some carbon on the inner or outer part of the track (or both) to change resistor value but it will increase doing so, not decrease.
It might mess the taper, I don’t know but I usually scrap some CTS for a higher value Volume, Treble and both OD controls and save a smaller value 1M for the Master.
You got to check often with your multimeter as it can go up slowly at first then tend to jump quicker and it’s easy to go up too far in value.
What’s the story about going to a 500k pot from a 300k improve the amp ?
I tend to use smaller pots on the bass with a slow taper to reduce bass (or at least it felt like less bass) but I might mess the PAB and make things worse.
mojotom wrote: ↑Fri Jun 25, 2021 9:13 pm
From my personnal experience you can use an Xacto knife and carefully remove some carbon on the inner or outer part of the track (or both) to change resistor value but it will increase doing so, not decrease.
It might mess the taper, I don’t know but I usually scrap some CTS for a higher value Volume, Treble and both OD controls and save a smaller value 1M for the Master.
You got to check often with your multimeter as it can go up slowly at first then tend to jump quicker and it’s easy to go up too far in value.
What’s the story about going to a 500k pot from a 300k improve the amp ?
I tend to use smaller pots on the bass with a slow taper to reduce bass (or at least it felt like less bass) but I might mess the PAB and make things worse.
They were talking bout not being able to find a 300k pot and how to get one, sounds like buy a 250k and then scrape to get it
As to why scraping increases the resistance....still confuses me. I first found this out when trying to "manufacture" a 346K trimmer for #0124
The carbon trace is a conductive element from the top of the pot to the bottom.
By removing some of the carbon your removing or decreasing the conductivity of the trace element therefore increasing resistance..Less carbon = higher resistance.
There is definitely an art to doing this and some practice and patience is required!..I do not recommend doing it on older (more than 10 yrs) NOS pot as you run the risk of flaking off or cracking the trace in half. The idea is to scrape around the inside and outside edges away from the path of the wipers pads again without cracking or chipping the element. A little goes a long way and be prepared to ruin a few pots figuring it out!
Ask me how I know
Tony
" The psychics on my bench is the same as Dumble'"
As to why scraping increases the resistance....still confuses me. I first found this out when trying to "manufacture" a 346K trimmer for #0124
The carbon trace is a conductive element from the top of the pot to the bottom.
By removing some of the carbon your removing or decreasing the conductivity of the trace element therefore increasing resistance..Less carbon = higher resistance.
There is definitely an art to doing this and some practice and patience is required!..I do not recommend doing it on older (more than 10 yrs) NOS pot as you run the risk of flaking off or cracking the trace in half. The idea is to scrape around the inside and outside edges away from the path of the wipers pads again without cracking or chipping the element. A little goes a long way and be prepared to ruin a few pots figuring it out!
Ask me how I know
Tony
Hello everyone! I'm planning to have a new version of the boards produced soon, and I'd love your feedback. What are some things you would like changed in the boards? Are there some errors you found that I can correct in the next revision? Any comments regarding the documentation?
I saw some of your builds in the forum using my boards, and that made me quite proud and happy to see them in use! any feedback or suggestion is welcomed!
Love from London,
Andrea
I have not read through the entire thread yet (so perhaps there is an answer already to the ticking problem), but am finding it VERY helpful. I have three of the PCBs and three of the same chassis and plan build each of the three different ODSs.
Regarding your ticking, did you happen to have your phone in your pocket or nearby?
frusciante89 wrote: ↑Thu Dec 02, 2021 12:11 am
Hello everyone! I'm planning to have a new version of the boards produced soon, and I'd love your feedback. What are some things you would like changed in the boards? Are there some errors you found that I can correct in the next revision? Any comments regarding the documentation?
I saw some of your builds in the forum using my boards, and that made me quite proud and happy to see them in use! any feedback or suggestion is welcomed!
Love from London,
Andrea
Hi Andrea, I am a happy owner of two of your boards and I used one fo them to build a clone # 183, you can also see it in the construction examples you published.
I plan to build a #102 and I have not yet purchased the new boards but in the old ones I found an error in the connection of the bias diodes (easily correctable) which I solved thanks to the feed back of another construction enthusiast contacted thanks to your blog.
Hope this problem has been solved.
Moreover, I had great advantage from the use of your board which has greatly simplified the construction which is more orderly and easier than with the use of eyelet cards.
For the foreseeable future I am very interested in building Fender Blackface type amps with the modifications suggested by H. Dumble,
Thank you
First of all thanks for posting this excellent information - you've inspired 3 of us to attempt a #183 build! The assembly from the pics looks extremely nice, too - may I ask what type/gauge/make of hookup wire (and coax) you're using for the assembly?
