Search found 45 matches

by chaccmgr
Mon Apr 22, 2024 8:33 am
Forum: Dumble Discussion
Topic: Signal resistor type
Replies: 11
Views: 580

Re: Signal resistor type

RG wrote a great article on resistors and their sound/noise and where to use and where not
http://www.geofex.com/ search for "Using the Carbon Comp Resistor for Magic Mojo" on the starting page
by chaccmgr
Thu Mar 21, 2024 3:40 pm
Forum: Speakers and Cabinets
Topic: Question covering with one piece of Tolex
Replies: 10
Views: 365

Re: Question covering with one piece of Tolex

or use painter's pyramids
by chaccmgr
Thu Mar 21, 2024 1:42 pm
Forum: Fender Discussion
Topic: Can I use a Bassman 70watts PT and OT for a Deluxe reverb?
Replies: 12
Views: 487

Re: Can I use a Bassman 70watts PT and OT for a Deluxe reverb?

the DR reverb has trannies that are undersized for the circuit by design, esp. the PT this leads to sag and compression which makes an important part of the DR's sound and feel if you build it with way oversized trannies, you will lose that. The preamp should be probably quite similar between a DR a...
by chaccmgr
Thu Mar 21, 2024 1:35 pm
Forum: Speakers and Cabinets
Topic: Cabinet made of OSB instead of pine
Replies: 13
Views: 542

Re: Cabinet made of OSB instead of pine

I would stay away from OSB. Marshall used it for some time but the cabinets are desintegrating with vibration over time (keep a vacuum cleaner handy) MDF is heavy as lead and does not withstand stress on the edges very well almost everybody uses 18mm/1/2" plywood today, if reinforced, you might get ...
by chaccmgr
Thu Feb 29, 2024 9:54 am
Forum: Dumble Discussion
Topic: SSS heater lead dress
Replies: 12
Views: 449

Re: SSS heater lead dress

in my designs I used both approaches and never had a hum issue. Lately I stick to Merlin's approach using the gap between Pin 1 and 9 make sure that other wires have a good clearance to the heater wiresand if necessary at all, let them cross in 90° angle or loop them over the socket. I prefer loopin...
by chaccmgr
Thu Feb 29, 2024 9:46 am
Forum: Technical Discussion
Topic: Does Bias 1 ohm resistor tolerance matter?
Replies: 5
Views: 228

Re: Does Bias 1 ohm resistor tolerance matter?

most multimeters have problems measuring small resistances exactly... If you don't have access to a trusted one, maybe comparing measurements from different multimeters give you a feeling of how far your multimeter(s) is/are off I know, this is not a solution but shows if your eqipment is the proble...
by chaccmgr
Wed Sep 20, 2023 12:40 pm
Forum: Fender Discussion
Topic: AB763 circuits - cathode bypass caps that are 47uf/100v.
Replies: 9
Views: 46763

Re: AB763 circuits - cathode bypass caps that are 47uf/100v.

Merlin Blencowe offers a ton of understandable documentation here. see http://www.valvewizard.co.uk/localfeedback.html for calculating feedback and frequency response see http://www.valvewizard.co.uk/OtherStuff.html for capacitor values and effect on the frequency response of a gain stage. Both 47µ ...
by chaccmgr
Thu Jul 06, 2023 10:32 am
Forum: Technical Discussion
Topic: 1U power amp 2×20w- any ideas for a build?
Replies: 19
Views: 2102

Re: 1U power amp 2×20w- any ideas for a build?

the marshall gut shot looks like a reasonable concept for your case. A band member used it and it sounded good. You could order a custom made toroidal PT. I'm located in Germany, whenever I need a special PT I order from polish http://www.badel.pl/, they always made whatever I nedded at a price that...
by chaccmgr
Thu Jun 22, 2023 1:50 pm
Forum: Dumble Discussion
Topic: Adjust BIAS on Dumble amps
Replies: 12
Views: 1445

Re: Adjust BIAS on Dumble amps

www.reichelt.de is a good source for e.g. resistors. They offer 0,1% tolerances (should be more than enough for this purpose) I generally use 5%/2W Metal Oxide for safety margin. I always measure them before I solder and the tolerances are generally much tighter than 5% their pricing is very reasona...
by chaccmgr
Fri Mar 31, 2023 11:10 am
Forum: PCB Design
Topic: Klon Centaur Gerbers - anyone?
Replies: 6
Views: 2874

Re: Klon Centaur Gerbers - anyone?

see your PM
by chaccmgr
Thu Mar 30, 2023 12:28 pm
Forum: Technical Discussion
Topic: Speaker Line Out Isolation Transformer question
Replies: 2
Views: 429

Re: Speaker Line Out Isolation Transformer question

also don't know theirs, I use a 600:600 type with pleasing results (https://www.monacor.com/products/pa-technology/signal-processing/signal-optimisation/ltr-110/). Cheap and working. Don't know if these are available where you live, in case yes, this one is unshielded and needs a placement where no ...
by chaccmgr
Thu Mar 30, 2023 11:58 am
Forum: Dumble Discussion
Topic: Ryan & Erwin's SSS #002 Madness
Replies: 187
Views: 29611

Re: Ryan & Erwin's SSS #002 Madness

Hi Volker, I usually buy most tube related stuff at www.tube-town.de. Cable-wiese I use silicon insulated wires wherever possible. Also a good forum there (in German)
also good for electronics supply in general is www.reichelt.de
by chaccmgr
Thu Mar 23, 2023 11:04 am
Forum: Technical Discussion
Topic: Where tone comes from?
Replies: 2
Views: 561

Re: Where tone comes from?

yeah, I also love the video about the guitar itself, ending up without any wood at all and still having basically the same tone
https://www.youtube.com/watch?v=n02tImce3AE&t=369s
by chaccmgr
Wed Mar 01, 2023 3:49 pm
Forum: PCB Design
Topic: PCB SIL sockets - will these be suitable for a tube amp board.
Replies: 6
Views: 1991

Re: PCB SIL sockets - will these be suitable for a tube amp board.

where is the point to use sockets and then solder the legs? How do you want to fix them to the board?

also my advice: turrets or eyelets
by chaccmgr
Thu Jan 19, 2023 10:34 am
Forum: Technical Discussion
Topic: Hiwatt DR201 OT - Tube Town vs TAD
Replies: 9
Views: 760

Re: Hiwatt DR201 OT - Tube Town vs TAD

No, I used it, it is 200W (actually 250W)
Note: Tube-Town is a German vendor, so the weight unit is kilograms not lbs (equals roughly 11lbs) :D