Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Time to play with this one

Had to borrow a fuse holder cap and a fuse and put it on the big ugly DBT with 60w bulb

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Next input signal 1Vp-p and hooked scope probes to input and (16 ohm) output
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Input channel one and output channel two

Amplifier power off (ch 1 at the bottom)

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Next amplifier power on and had aux volume at half and master volume at half
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Not much amplification going on  :grr
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Next I tried to max out both volumes and see the result but it started flattening out the top of the output

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The most output I could get is about four Vp-p

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 xP

Now...granted there are a bunch of switches on the back so who knows
And...idk what I'm doing  :'(
So there's that but it looks like it works to me idk  :lmao:

One really wierd thing that happened...I could hear a very faint hum with the power off.  I leaned in to listen better and thought wow is that my 1 khz signal ?! So I reached up and changed the frequency and yes it was my signal I could hear it with the amp power off  :loco

I'm gonna propose that the above is probably not SOP for amp testing  :tu:  :loco

I'm gonna connect a speaker and see if I can get ear bleeding 1 khz  :tu:  :lmao:

Alright well either
-im not doing this correctly
-or this amp is putting out one watt  :lmao:

So I -connected an 8 ohm speaker
-Scope leads across speaker terminals
-Maxed out aux and master volume
-increased signal until output started clipping (about 2.8 Vp-p)

Did math
IMG_20251027_193140650.jpg

 :grr

So I guess I have a sick one here  xP

Meanwhile it cut off a few times I could hear a distinct click whenever it did.  It was not intermittent it wouldn't come back until I turned it off and turned it back on after s moment.
And the fuse is good.
I guess that explains why all the cover bolts were missing

A couple things I noticed about this amp is there is no relay click maybe it's not supposed to have one because it "works" with out it.
Also I noticed the bottom panel gets warm
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 but I saw a video pointing out that the output transistors are attached to the bottom panel
IMG_20251027_192957130 (1).jpg

So right off the bat I suspect a bad voltage regulator  :lmao: