Often when I buy or receive old tubes, pins on the tubes are oxidized. Big issue with oxidation is that it prevents pins making good contact with the socket. Because of that in the worst case, tube would appear to be completely dead or it will make strange noises during playback. Fixing this issue is quite simple. Just pray pins with DeoxIt D5, wipe in with a cloth and the problem will be solved in the majority of cases. If that don’t help, sometimes using a small screwdriver and cleaning pins one at a time to remove junk off the metal. They spray with Deoxit again to ensure that what ever is left is dissolved.
Category Archives: Guides
Deciphering European tube date codes
A lot of questions have been asked about when a tube is made, so here you go, a quick guide on how to decipher the date codes.
For the most European tubes made after 1955 date codes are located on the bottom of a sidewall of a tube (not always the case)
In this case, it’s B0D (this is for Mullard, Blackburn – 1960 – April)
Tubes with Black and Gray plates

The debate regarding black versus gray plate vacuum tubes is a recurring topic in the audiophile community. While some skeptics argue that the preference for black plates is a marketing myth designed to justify higher price points, many enthusiasts maintain that they offer superior performance in high-fidelity systems. To understand the merits of each, one must look at the underlying physics of tube operation.
Continue readingReissue vs. Vintage Power Tubes
Globe vs ST shape tubes
Fun article about Globe vs Shoulder type tubes with great tube pictures 🙂
Pre-amp tube matching
And here we go again – tube matching, this time preamp tubes – the topic will never end, but I hope to bring some clarity to it
Voltages and money – your guide to savings

In the world of high-end audio, we often ask: does “one size fit all”? While the answer is usually no, you can find absolute treasures in places where others aren’t looking.
Continue readingTo Match or Not to Match – Power Tubes
A few articles to help you figure out if matching is important for you.
The Sound of Rectifier

A common debate among audiophiles is whether the choice of rectifier tube significantly alters the sonic profile of an amplifier. To investigate this, I conducted a series of tests using a flexible amplifier circuit designed for a 5U4 rectifier, allowing for direct comparison with 5Y3, 5Z3, 5AR4, and solid-state alternatives.
Continue readingBuying tubes on Ebay
Buying tubes on Ebay could be a lot of fun, but at the same time is very complicated and very frustrating (based on the personal experience), because you never know if the tubes you are going to get are going to work or last beyond a week or a month.
There are steps that you can take to avoid fraud and enjoy the newly acquired treasures for a long time:
- This one goes without saying – check feedback!!! If you see that there are complains, the price is irrelevant – you will be toughing away your money.
- Make sure that the seller allows returns – a lot of sellers don’t take returns on tubes, which doesn’t make sense. All the risk is then on you. Ebay has an idiotic policy that it doesn’t evaluate “subjective” statements like “Strong” or “Weak”, so the seller can claim the tube to be strong, but you get a weak tube and good luck to you if there is not return policy. You are stuck with a fantastic and very expensive piece of junk.
- Buy from a reputable dealer – get your tubes from a reputable dealer that specializes in tubes. Yes the price is a bit higher, but the tubes that you buy would last 2-3x longer.
- Check test results!!! – no test results, no purchase. Don’t buy tubes that just state that they test good – that’s garbage. If seller tested a tube and states so, there must be test results listed. It gets very complicated here since different testers how different test results. Try to get tubes from a seller that has transcondactance tester – usually stated in millimho, micromho or gm. Emission tester is just no good – I have a lot of tubes that test 95% on emission and are practically dead. Look for names like Hickok, B&K, TV, Western Electric.
Have fun!!!






