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Messages - Jazz P Bass

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The output transistors that you picked are way overkill for the amp that you are designing.
Yeah, they will work.
But still.
Way over the top.

Amplifier Discussion / Re: Peavey VSS-20 amplifier with chorus noise problem
« on: September 27, 2020, 10:13:08 PM »
Have you checked the 'digital +9vdc supply'?
It should be pretty free of any ripple voltage (Vac).

Amplifier Discussion / Re: Peak dissipation in class B output stage
« on: September 22, 2020, 11:43:35 AM »
I would build a tried & true amplifier.
Attached is a simple low power amplifier.
Tube Works TD 742.
Build it.
Study it.
Blow it up.  :lmao:

The Newcomer's Forum / Re: Roland JC-120 with weak reverb
« on: September 19, 2020, 12:45:40 AM »
A TA-7200 P 10 watt power amplifier is used to drive the reverb pan.
It appears to be a 1.1 Vac output signal on the schematic.
Measure it and see what you have.

Schematics and Layouts / Re: G-K Gallien-Krueger MB112 ICEpower
« on: August 29, 2020, 11:57:36 AM »
ICE Power schematics have never been released as far as I know.

Tubes and Hybrids / Re: Blackstar HT5 noisy Clean channel
« on: August 16, 2020, 01:19:15 PM »
I have attached the input circuit diagram.
The signal branches off of IC2A to the Clean and the Crunch channel.
Either of those is selected by jfets. (Clean/ Fet1: Crunch/ Fet2)
You will need to track down where in the Clean circuit the signal is failing.

" switchmode amplifier, PWM (pulse width modulated) amplifier and Class-D amplifier"

Amplifier Discussion / Re: peavey musician series 400
« on: August 08, 2020, 01:09:50 AM »
!!!"  DISCONNECT any speaker"!!!

The Newcomer's Forum / Re: FX loop noise
« on: August 06, 2020, 11:43:38 AM »
Try the guitar into the Zoom & then go into the FX Return jack.
This will tell if it is a Send circuit issue or a Return circuit issue.
Be aware that you may have to adjust the gain on some of the Zoom presets.

Amplifier Discussion / Re: Crate G130C Amp
« on: July 24, 2020, 12:51:35 AM »
To answer the posts question, here is a crop of the power amp board locating D16 (+16Vdc) and D17 (-16Vdc)

Amplifier Discussion / Re: Crate G130C Amp
« on: July 23, 2020, 11:51:25 AM »
Piease post the relevant schematic.
You really should test the power supply before assuming the failure mode is the exact same.

-7Vdc on the speaker out connection indicates a failed output section.
The lower minus part is turned on when it should not be.
Do not hook up the speaker until this is resolved.

You will have to remove the old solder from the PCB before you install the new jack.
You will need a solder sucker,
Or 'solder braid'.

Amplifier Discussion / Re: Peavy 130 Special needs some TLC
« on: July 10, 2020, 12:09:48 PM »
Here is the schematic.

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