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.
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!
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.
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.
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.
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.
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.