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1963 Hohner Concertophon III tube amp: 15W EL84 pushpull crunch!



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A 1963 incarnation of the Concertophon, with three triodes for preamp and tremolo, one for the phase inverter, pushpull EL84s and EZ81 rectifier. 2 x 10" speakers... not the best. The first step was basically a repair, fixing some dead solder joints on the cathode of V2.
#tubeamprepair #hohner

00:00 Intro
00:23 Hohner?
01:47 Controls & inputs
04:01 Inside the amp - firing up
05:03 Problem Desert Storm
06:10 Checking the controls
07:15 Plugging in & spanking amp
08:04 Power section
09:10 Telefunken tubes
10:58 Dating the tubes
12:38 Tracking down the problem
13:54 Replacing input jacks
14:40 Tone Sucker circuit found!
15:05 Preamp circuit analysis
15:58 Preamp layout
17:15 Removing the tone sucker
18:37 Parts in a baggie
19:03 New bypass caps
19:53 Test with 12" Eminence Swamp Thang
22:05 Fixing the tremolo
22:45 Tremolo test with 1 x 12"
24:30 Installing 3 prong power cord
25:13 Output transformer configuration
26:10 Test with stock 2 x 10" speakers
32:03 Summing up
Category
Audio
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