Search found 1662 matches

by erwin_ve
Mon Mar 11, 2024 2:22 pm
Forum: Dumble Discussion
Topic: OTS #102 to #060 (without reverb)?
Replies: 51
Views: 2630

Re: OTS #102 to #060 (without reverb)?

I’m not an expert but it looks likely to be a carbon film resistor to me. The TT xicon resistors are good quality. For the 1uF I’d opt for the standard TT electrolytic. Alpha’s are decent pots. If you look at the AN gutshot, you can see where he is putting the RN65s (e.g. plates) and where he’s usi...
by erwin_ve
Sun Mar 10, 2024 4:55 pm
Forum: Dumble Discussion
Topic: #002 Steel String Singer - almost there
Replies: 69
Views: 3003

Re: #002 Steel String Singer - almost there

Lothy wrote: Sun Mar 10, 2024 3:44 pm Here is a quick demo:



Cheers
Gerhard
Congrats, sound great!
by erwin_ve
Fri Mar 08, 2024 3:19 pm
Forum: Technical Discussion
Topic: What do you believe regarding the sound of passive components?
Replies: 185
Views: 5594

Re: What do you believe regarding the sound of passive components?

Another good reference to add to the pile. Take note of the magnitudes of the differences shown in the charts, and the frequency scales, though. If a 1 or 2 ohm resistor were added in series with a cap, would that be noticed at audio frequencies? Do differences above 20 kHz even matter? What about ...
by erwin_ve
Fri Mar 08, 2024 8:23 am
Forum: Technical Discussion
Topic: What do you believe regarding the sound of passive components?
Replies: 185
Views: 5594

Re: What do you believe regarding the sound of passive components?

This is one of my favorite pics to demonstrate measurable differences exist between different dielectrics. Now, the hard part is quantifying that, and translating to how it will sound in a guitar amp. It's clear that one of these caps is superior if you're going for minimum THD, for something like ...
by erwin_ve
Thu Mar 07, 2024 3:24 pm
Forum: Dumble Discussion
Topic: Dumble ODS #22
Replies: 15
Views: 975

Re: Dumble ODS #22

Here's some background info from the original owner; https://www.youtube.com/watch?v=I94Gw4JJyZs
by erwin_ve
Wed Mar 06, 2024 6:49 pm
Forum: Technical Discussion
Topic: What do you believe regarding the sound of passive components?
Replies: 185
Views: 5594

Re: What do you believe regarding the sound of passive components?

Maybe just lock this thread. We get to a point where mocking and heated comments taking over.
by erwin_ve
Tue Mar 05, 2024 8:26 pm
Forum: Dumble Discussion
Topic: 2nd Gen Build Started (that didn’t take long…)
Replies: 316
Views: 9711

Re: 2nd Gen Build Started (that didn’t take long…)

I connected as written and the OD is pretty fantastic. Definitely a different flavor than 102. All switches and pots work as they should, but Manual/Pedal didn’t cut off the sound when I switched to pedal. Could I have a defective switch as well? Looking at it - it would seem to me that the switch ...
by erwin_ve
Mon Mar 04, 2024 8:13 pm
Forum: Technical Discussion
Topic: What do you believe regarding the sound of passive components?
Replies: 185
Views: 5594

Re: What do you believe regarding the sound of passive components?

Equivalent series inductance makes the impedance of a resistor plus ESL higher with frequency. The frequency where the inductive reactance equals the resistance is taken as the critical point of its filtering. The frequency were that happens is F = R / (2 * pi * L). I did a quick look for the self ...
by erwin_ve
Mon Mar 04, 2024 7:28 am
Forum: Technical Discussion
Topic: What do you believe regarding the sound of passive components?
Replies: 185
Views: 5594

Re: What do you believe regarding the sound of passive components?

Did anyone read, besides Martin, the Bateman files I posted in this thread? Real numbers there :evil:
by erwin_ve
Sat Mar 02, 2024 9:11 pm
Forum: Dumble Discussion
Topic: HRM Bluesmaster 50 PI trimmer help
Replies: 19
Views: 949

Re: HRM Bluesmaster 50 PI trimmer help

I am learning as we go so I will spell things out so I have a reference when I need to come back to this. I have moved the signal cable from the front high input jack to the loop input jack on the rear. The layout diagram shows power amp in. I injected 400Hz at 1.5Vrms which gave me a plate voltage...
by erwin_ve
Sat Mar 02, 2024 8:04 pm
Forum: Dumble Discussion
Topic: HRM Bluesmaster 50 PI trimmer help
Replies: 19
Views: 949

Re: HRM Bluesmaster 50 PI trimmer help

When I connect the DMM probe from V4 pin8 and the second probe to V5 pin 8 I can now zero it. I assume from here I just need to do slight adjustment by ear to get it slightly out of phase? Would that result in a + or - voltage reading on the meter? Does this procedure need to be redone whenever a t...
by erwin_ve
Sat Mar 02, 2024 7:46 pm
Forum: Dumble Discussion
Topic: HRM Bluesmaster 50 PI trimmer help
Replies: 19
Views: 949

Re: HRM Bluesmaster 50 PI trimmer help

I gave the Ampeg procedure a try. I set the power tube bias to 34v. Both tubes were showing 34v on the DMM. I injected a 400Hz signal at 1.5 Vrms into the high input jack I adjusted the master volume for an output of 18Vrms at the 8 ohm dummy load Using a DMM I connected the black probe to the chas...
by erwin_ve
Fri Mar 01, 2024 7:18 pm
Forum: Technical Discussion
Topic: What do you believe regarding the sound of passive components?
Replies: 185
Views: 5594

Re: What do you believe regarding the sound of passive components?

bepone wrote: Fri Mar 01, 2024 6:08 pm noise is the difference in sound between the resistor types? :lol: :lol:

i heard everything in my life.. but this.. :mrgreen:
Did you read the post above yours from Martin?
The researchers considered the possibility of non linear behavior due to noise. Interesting stuff!
by erwin_ve
Fri Mar 01, 2024 4:41 pm
Forum: Technical Discussion
Topic: What do you believe regarding the sound of passive components?
Replies: 185
Views: 5594

Re: What do you believe regarding the sound of passive components?

martin manning wrote: Fri Mar 01, 2024 4:37 pm Metal film resistors are not all equal in noise, and this has been measured. Whether it's audible by humans is another question, since they are in general so much superior to CF that the difference between MF's seems negligibly small.
That might be a explanation I won't rule out.