1967 120W Geloso G.1/1110 Tube Amp

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There are fuses taped all over this +100W beast…. looks like professional artists: Animations & Spectacles. Here’s the story on the original owners of the amp.

I cut out the two yellow death capacitors: img_5816

The power chord was cut and should be replaced by a modern 3 prong cord.img_5815

New 3-prong grounded power cord installed. After removing the death capacitors, the grounding point is free to connect the common wire from the three prong cord.

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1969 Geloso G.1/1040 40W EL34 Tube Amp

Here’s another nice vintage Geloso tube amp, though already dating from 1969.  With two EL34 tubes, it sports a nice 40W of output power.

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Unfortunately, it’s not working, and the reason is clear from these voltages: there’s only coming 245-260V off the solid state rectifier.

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With the tubes removed, the voltages are up to scratch: 360V

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1966 Geloso 3215 Tube Amp

It may be due to Flanders irrevocable ties to the Holy See or just because of the numerous musical Italian immigrants, but there are a lot of Italian Geloso amps for sale in the low countries.

Giovanni (John) Geloso (1901 – 1969) was an Argentinian immigrant who established one of the most important electronics factories in pre and postwar Italy.  More information on the Geloso company can be found here.

This is a 17W 1967 Geloso G3215:

img_5308An 1967 handwired, all tube 17W amp running a set of tubes very familiar to the guitar player and hence affordable!  ECC83 or 12AX7 for the preamp, EL84 power tubes and a EZ81 rectifier. In fact, this is the exact tube complement of an earlier incarnation of the Vox AC15.

Filaments of the preamp tubes are run off negative DC, which assures absolutely noiseless operation. And there is the extra filter coil often omitted in guitar amps.

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This amp still had all the original Geloso branded tubes:

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The amp was sold to me in working condition. In the context of tube celexa 20 mg technology, this often means, the tubes glow up.  So it was in this case, tubes glowed, but no sound.  Things only changed when I changed the mains power switch from 240V to 220V – then this little Italian beast came to live.  It is loud, noiseless and has absolutely cheap buy generic nexium online without rx acceptable guitar tone.  I decided to install an input jack and keep the amp stock for now.  The big yellow capacitors are not Geloso, but Sprague, date coded 1966, 26th week.

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Input jacks are shielded from the rest of the circuit.  The wiring is to a very high standard as are the components, who are holding up perfectly, even after half a century.

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An additional advantage of these Geloso amps is that they allow you to drive any speaker from 1.5 ohms up to a 1000 ohms.

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For now, I installed speaker jack in such a way that you can switch the ends to different poles on the output transformer.

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Cleaned up, input jack and chicken heads installed:

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Tube Radio Guitar Amp: Part 3 Making Plans – Vox Pacemaker 1965

Yes, there is a very nice and decent guitar amp hidden inside this scruffy old Philips radio, all the components except a suitable output transformer and speaker are present to solder up this nice gem:

Huh? Why? How?

Power rectifier EZ81 — If you are in Europe and hunting for tube radio with any value in the guitar amp field, check for this rectifier tube. If you see it, buy the radio!  This tube is used is the early Vox amp, up to the AC15 as power rectifier.  Most vintage American amp you will be looking at require at least 3 different voltage from the transformers: a high voltage, 6.3V for the tube filaments and 5V for the rectifier. The EZ81 does not require the special 5V, just feeds off the high voltage.

phillipspowersectionIn this way, it is just like a Vox Pacemaker — although below schematic is from a Cambridge Reverb (the same amp + reverb):cambridgereverbpower

Or an AC-15, also using an EZ81:

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And all of these are unlike any 50’s Fender amp, which require three voltages on the transformer 6.3V, HV and 5V especially for the rectifier:

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Transformer and rectifier tube in a Fender 5E3 Tweed Deluxe amplifier.

2 Power tubes EL84 & 1 Preamp tube ECC83 — if the transformer can power this in our radio, we need only one extra ECC83 tube to make a Vox Pacemaker. It uses 2 x EL84, 2 x ECC83 and an EZ81.  The Philips radio powers and additional 5 tubes for RF purposes, so it is certain that this transformer from a piece of €10 junk can function as the heart of a Vox Pacemaker, Vox AC-15 or Marshall 18W…. value: $75. My calculation seems to indicate this transformer could pull 5.4A on the high voltage.  I don’t believe you could find one that would feed anything more than a 25W amp.

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The only thing that is missing, is the output transformer, which will cost around €50. Chassis, resistors (after measuring), 6.3V pilot light and mounting screw can all be salvage from the zombie corpse.

I really think you could use a lot of the power transformers in old radios, but the output transformers from household radio sets will never be strong enough.