120 Watt Power Amp build thread.

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Mihaly
Posts: 2
Joined: Thu Nov 01, 2007 2:52 pm
Location: Melbourne

Re: 120 Watt Power Amp build thread.

Post by Mihaly »

Don't think you need a LPF as the driver will naturally roll off. A HPF may be useful to get rid of really low crud, but make it switchable.

So Mick is a Strat player too, and in Melbourne. That's two of us. Have to set up a jam with all our JLM amps.....

Its a shame that there is not a kit for the Champ clone. I have an AC30, When its distorting its just so loud (no master volume). Actually built my 120W stereo to power two ~100W PA speakers for some synths.

Had a problem with one amp was distorting. Discovered that I failed to solder one end of three resistors - one of which was discovered only once I had bought some magnifying goggles to thouroughly inspect the work. Off to the Optometrist next week....

Cheers,
Mihaly.

chrisp
Posts: 184
Joined: Sun Mar 04, 2007 11:46 am
Location: Sydney, Australia

Re: 120 Watt Power Amp build thread.

Post by chrisp »

My input is going to be an unbalanced TS cable at nominal +4dbm. The pedalboard output impedance is <1k, with the load impedance at >10k.

Couple o'questions ....

(1) I assume that this can plug into the amp board simply by shorting the in- to 0V.

(2) I'd also like a DI out. Can I just wire a 1:4 in backwards (ie amp PCB in+ to secondary +, in- to secondary -. XLR pin 2 to primary +, XLR pin 3 to primary -, and XLR pin 1 to 0V) to achieve this?
Chris P
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I do lots of things. I believe eclectic skills are best.

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Joe Malone
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Re: 120 Watt Power Amp build thread.

Post by Joe Malone »

1) I assume that this can plug into the amp board simply by shorting the in- to 0V.
Yes just use a TRS socket so if you plug in a TS plug it will pull the ring -in to 0v and unbalance the input or if you plug a TRS plug in it will run balanced.
(2) I'd also like a DI out. Can I just wire a 1:4 in backwards (ie amp PCB in+ to secondary +, in- to secondary -. XLR pin 2 to primary +, XLR pin 3 to primary -, and XLR pin 1 to 0V) to achieve this?
Yes that should work fine
Joe :-)
JLM Audio
Capturing Audio without Injury

chrisp
Posts: 184
Joined: Sun Mar 04, 2007 11:46 am
Location: Sydney, Australia

Re: 120 Watt Power Amp build thread.

Post by chrisp »

Thanks Joe
Chris P
---------------------------------------------------------
I do lots of things. I believe eclectic skills are best.

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