Fatman iTube 252

Fatman iTube 252 Tube Amplifier Repair & Service

Check out this classic Fatman iTube 252 integrated tube (valve) amplifier I repaired and serviced in another article to help with COVID-19 boredom.

Silly name aside, the Fatman iTube 252 is a decent, compact 25 Watt per channel tube-based integrated amplifier. The iTube 252 uses 4 x EL34 pentode output tubes and four dual-triode tubes. Perhaps the coolest visual feature though is the 6E2 tube, a display tube somewhat reminiscent of a VU meter.

It’s a reasonably solid, well-made unit, using average quality parts. It’s also a vacuum tube-based product, so it needs more regular maintenance than a solid-state amplifier. Tubes wear out over time and must be replaced. Add in an unhealthy dose of cheap Chinese capacitors and you have an amplifier that will definitely need attention after 10 or so years.

Fatman iTube 252
The finished cleaned, repaired and serviced iTube Fatman 252

These amplifiers were relatively popular 10 – 15 years ago and reasonably well thought of as this What HiFi review shows. They also weren’t cheap, costing $2100 AUD back in 2008.

Problems

This iTube 252 came to me in desperate need of repair. Her owner had, in desperation, sprayed WD-40 into every opening to try to cure various operational issues. Don’t EVER be tempted do this, it creates real issues, not the least of which is a greasy mess that must be removed. Greasy mess aside, this amp had several blown and broken tubes. All tubes were worn out and even the display tube needed replacement. No amount of WD-40 was going to fix that.

If you are wondering how you can tell your tubes need replacing, well you might see the tell-tale signs of gas leakage from the haziness of tubes in these images. Your amp or preamp will lose its sparkle, it might lose power, gain hum and noise and it will just generally sound tired.

This amp also had leaky capacitors and other issues. Let’s fix it!

Fatman iTube 252
Looking forlorn, I’ve removed some dead capacitors and left the dead and dying tubes here for all to see.
Fatman iTube 252
This amp can’t run like this, though the owner did try, unfortunately.
Fatman iTube 252
Dead EL34. The haze indicates the tube has lost its vacuum, ie that gas has entered the tube, rendering useless.
Fatman iTube 252
Very dead 6E3. For those who don’t know, vacuum tubes can only work if there is a vacuum inside the glass envelope. With a hole in the top, there’s no vacuum.
Fatman iTube 252
With the tubes and bottom removed, it’s time for a really good clean to remove all that WD-40 residue.
Fatman iTube 252
A better view of the insides. Parts quality isn’t great, especially the electrolytic capacitors and the four black ones you see lying across the middle of this image are totally dead, and leaking.
Fatman iTube 252
Here they are in close-up. Note this one has been damaged by the cable tie having crushed the capacitor body.
Fatman iTube 252
These have to go

Cleaning and Repair

First steps are always clean, clean and clean again. You can’t effectively work on things that are dirty, especially not electronics that are covered in WD-40.

Fatman iTube 252
Here, I’ve thoroughly cleaned the iTube 252 and installed a set of Panasonic capacitors to replace the awful dead ones.
Fatman iTube 252
Close-up of the new Panasonic FC low impedance capacitors and newly cleaned board.
Fatman iTube 252
Everything is clean and non-greasy now and these capacitors will last a lot longer than the original parts did.

New Tubes

A major part of this overhaul involved installation of a new set of matched tubes. Budget plays a big part in determining what tubes I use in overhauls like this. In this case, I asked my tube supplier for a set of four carefully matched, improved JJ EL34 II output tubes, two matched JJ 6SN7 tubes, two matched JJ 12AX7 tubes. I sourced a new 6E2 elsewhere.

This is a solid set of tubes, much better than ordering super cheap unmatched stuff and hoping for the best. The EL34 II is a modern update to the EL34 and by all accounts is a great way to go. Note that this is still a budget tube-set and one could spend a lot more. My experience with JJ tubes has been positive though. This is a good budget set and matching the tubes to one another and triodes withing each tube makes everything run smoother and sound better.

Fatman iTube 252
We are not far off bringing this thing back to life with this set of lovely new JJ tubes.
Fatman iTube 252
Evidence of matching on the JJ El34 II boxes, which is nice.

Fatman iTube 252

Fatman iTube 252

Fatman iTube 252
More evidence of matching, this time of the JJ 6SN7 tubes.

Of course, I also cleaned and serviced all the switches and controls and just tidied things up as I went. This is all part of the service.

Results

In short, this Fatman iTube 252 came up amazingly well after this clean, repair and service, like new in fact. With no more greasy controls and switches restored and with new capacitors and a full new set of tubes, this amp runs like a dream. She also sounds fantastic, really good for what is still a fairly modest design.

Sure, it’s a low-powered design and it will definitely not drive normal speakers to high levels, but it does sound warm, smooth and relaxed, three eminently desirable qualities in equipment designed to reproduce sound. These days, Fatman iTube 252s go for only a few hundred bucks and at that price, even once you’ve factored in a major service like this, it’s a great deal.

Fatman iTube 252
She looks good too, especially with slightly dimmed lighting!
Fatman iTube 252
I wish you could see the 6E3, pulsing with the music. It looks cool, no doubt.

Fatman iTube 252

Fatman iTube 252

Fatman iTube 252

Fatman iTube 252

Anyhow, I hope you’ve enjoyed this article and that you are staying safe and well. If you’d like me to give your valve/tube amplifier a little TLC, don’t hesitate to let me know.

Feel free to leave a comment!