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Suggestions for Bass/Guitar preamp to pair with TDA8932B P.A.?
by saturated
[Today at 03:40:03 PM] -
Viva I'Italia
by saturated
[Today at 12:32:12 PM] -
Randall RG75D poor audio quality at speaker
by J M Fahey
[Today at 01:14:02 AM] -
Randall RG1003 issues changing channels
by anderson4584
[July 15, 2025, 03:59:54 PM] -
Revv G20 wiring help
by blackcorvo
[July 15, 2025, 12:06:02 PM]
Recent posts
#1
Preamps and Effects / Re: Suggestions for Bass/Guita...
Last post by saturated - Today at 03:40:03 PMIt started out like geddy and ended up like geezer 
#2
The Newcomer's Forum / Re: Viva I'Italia
Last post by saturated - Today at 12:32:12 PMYes sir thanks after watching that I remembered so many times waiting for what seemed like an eternity for solder to melt.
especially outside sitting there sweating or whatever
Or the solder melts and it's this big blob that sticks to the tip and it refuses to go where I want it to so it's like a booger on your finger you can't get off 
Also wow I also used to think that every soldering iron tip had to look like an ice pick
(I know somewhere those ice pick tips have a purpose but idk what it is)
especially outside sitting there sweating or whatever Or the solder melts and it's this big blob that sticks to the tip and it refuses to go where I want it to so it's like a booger on your finger you can't get off
Also wow I also used to think that every soldering iron tip had to look like an ice pick
(I know somewhere those ice pick tips have a purpose but idk what it is)
#3
The Newcomer's Forum / Re: Viva I'Italia
Last post by g1 - Today at 11:21:37 AMI was taught that leaving the sponge soaking wet like that was a mistake, and it should be squeezed out so it is just damp. You don't want to be sticking the tip in water.
#4
Preamps and Effects / Re: Suggestions for Bass/Guita...
Last post by saturated - Today at 06:12:45 AMI thought it was killer 
Almost heard a little N.I.B. at 5:27
Almost heard a little N.I.B. at 5:27
#5
Preamps and Effects / Re: Suggestions for Bass/Guita...
Last post by blackcorvo - Today at 02:12:11 AMHere's a video update showing the passive compressor working, and a second solution I came up with that I feel works better and is simpler.
The simpler solution is an AGC circuit:
But with the clipper using 2 LEDs instead of an LED and a diode, and only a series 100R resistor, no capacitor.
Next I wanna try a rectifier with the LED in the middle (like the diode clipper in a JCM900) and see how that does, reason being that in the 2 LEDs clipper, the LEDs are only on for the half of the signal each clips, while with a rectifier the LED will clip both sides of the signal.
[Edit]
Attachments added for the tone stack curves with the switch at different settings, and the project layout.
Also of note, I changed the capacitor to be wired like a typical Marshall mid control instead of how it originally was (morelike a Fender), which makes it so turning all tone knobs down doesn't cut the signal completely, and gives IMO better isolated control over the mids.
The simpler solution is an AGC circuit:
But with the clipper using 2 LEDs instead of an LED and a diode, and only a series 100R resistor, no capacitor.
Next I wanna try a rectifier with the LED in the middle (like the diode clipper in a JCM900) and see how that does, reason being that in the 2 LEDs clipper, the LEDs are only on for the half of the signal each clips, while with a rectifier the LED will clip both sides of the signal.
[Edit]
Attachments added for the tone stack curves with the switch at different settings, and the project layout.
Also of note, I changed the capacitor to be wired like a typical Marshall mid control instead of how it originally was (morelike a Fender), which makes it so turning all tone knobs down doesn't cut the signal completely, and gives IMO better isolated control over the mids.
#6
Amplifier Discussion / Re: Randall RG75D poor audio q...
Last post by J M Fahey - Today at 01:14:02 AMQuote from: smackoj on July 15, 2025, 04:35:58 PMHi friends; A very long time away so apologies. I did a quick cleanup on this Randall RG75D model SS amp. Built in China with one 12" spkr. This amp is almost silent at idle but start playing thru it and it sounds poor with some kind of high freq noise on every note. I checked the speaker wires and there is .25 vdc on them at idle. Is that enough dc to cause a problem? thanks amigosNot by itself.
Disconnect those speaker spade terminals and try the amp with another speaker or cabinet.
Also connect another amp to the internal speaker.
So we know whether it´s an amp or speaker problem.
#7
Amplifier Discussion / Randall RG75D poor audio quali...
Last post by smackoj - July 15, 2025, 04:35:58 PMHi friends; A very long time away so apologies. I did a quick cleanup on this Randall RG75D model SS amp. Built in China with one 12" spkr. This amp is almost silent at idle but start playing thru it and it sounds poor with some kind of high freq noise on every note. I checked the speaker wires and there is .25 vdc on them at idle. Is that enough dc to cause a problem? thanks amigos
#8
Amplifier Discussion / Re: Randall RG1003 issues chan...
Last post by anderson4584 - July 15, 2025, 03:59:54 PMQuote from: J M Fahey on July 11, 2025, 03:02:08 PMQuote from: anderson4584 on July 10, 2025, 10:56:55 AMI can always change to channel 3. But I have issues getting it back to channels 1/2. I opened up the footswitch and everything seems fine in there. I played with the wires a little bit to see if it would change anything and the only thing that changed anything is.......it typically works fine when I hold the footswitch upside down.
That makes no sense.
Do you hold pedal in your hand or put in on the floor? (so floor can push both buttons at the same time)
I know... it's TOTALLY insane. So it was doing it when I held it in my hand. I've since rested it on the desk my amp+cab is on upside down and I just press down whichever side I need.... and it totally works. It TRULY makes no darn sense. It is NOT pushing both at the same time. I make sure of that.
QuoteWhen this issue happens, I also typically lose a lot of power output while playing, but ONLY in the bridge pickup. If I switch to the neck pickup, I get power back. That makes even less sense..
I know. I've never come across anything like this. I got all weird and started swapping guitars thinking it was an issue with my guitar. Nope same issue with other guitars.
-QuoteTried using another 2 switch footswitch I have that goes to a Peavey classic 20MH (this works... but it ends up having the same issue, which leads me to believe it's the amp).I am at work and about to leave. I'll try this as soon as I can, but I have family over. So it may be a few days unless I can manage to find time to do this while they're here. Thank you for your time. I'll come back with results one way or the other.
-Swapped some cables around, and tried different guitars.
For testing, plug a spare TRS/"stereo" plug in theb Fsw jack.
Cover open, pins visible.
Solder a short (1" to 2") piece of wire to plug ground terminal.
Then touch either of free pins (to simulate temporary switch) with the free end ... what happens?
Repeat test but now soldering wire end to a pin or another to simulate a latching switch.
This way you are testing using a bare minimum "pedal equivalent" device, very simple and easy to understand, which depends on nothing else.
Post results.
#9
The Newcomer's Forum / Viva I'Italia
Last post by saturated - July 15, 2025, 02:43:25 PMYes Viva I'talia for this
#10
Amplifier Discussion / Re: Revv G20 wiring help
Last post by blackcorvo - July 15, 2025, 12:06:02 PMYes, photos would be helpful. But a better question is: where do these wires go? Are they for connecting two boards? A transformer? Looking at that and where the traces going to those connectors can help a lot if you don't have a schematic, but know what is usually connected to where (ground to ground, secondary to rectifier, and so on).