Bad Tubes – Bad Bad Tubes

Bad Tubes - Bad Bad Tubes

Well, I finally had some tubes go “bad” on me or “become microphonic”. When I purchased my Doge 8 one thing I didn’t like was that it used 4 12AT7 tubes for the line stage. I liked the idea of 12AT7 because they can really change the music. However, it is tough to get a quad of matched tubes. Originally I was going to get a quad of Bugle Boys from VTubeAudio but only 3 of the 4 matched. I passed on them and wish I hadn’t.

Amperex Bugle Boy 12AT7 / ECC81
Doge 8
Amperex Bugle Boy Halo Getter

After talking with www.VTubeAudio.com we decided the quad didn’t match and I passed on them and decided to try my luck on a cheap set to get me by from another company until VTubeAudio had something I really wanted that matched. 

Brimar 12AT7

Pay attention kids because here is the lesson in this post. Do not buy cheap tubes. I found a quad that was said to be a matched and NOS Brimar 12AT7 quad. The price was right and I purchased them.

I rolled them in and gave them some warm-up time before running some Sade on vinyl through them and seeing what they were made of. I was happy enough with them. After some time to burn in and settle they really had the same sound as when they were first rolled into the preamp. I was skeptical about them being true NOS tubes at this point though. Usually, true NOS tubes will adjust and change through the first 10 hours at least before they settle down, or that has been my experience with tubes. I purchased a pair of Mullard 12AT7 / CV4024 ( Rebranded BEARD M8162) tubes from VTubeAudio a while back and it was awesome listening to them change and finally settle in. Now they don’t leave the amplifier they are in.

Mullard CV4024

After 2 weeks with the Brimars, I noticed one afternoon that I could hear the volume being adjusted through the speakers. I don’t mean the music playing louder and softer I mean the actual volume pot being adjusted. It had a mechanical sound that took me off guard. Initially, I thought It must be the tubes adjusting and it would go away, but it continued to get worse. Word to the wise: shut your system down if you have anything sounding odd. I did have a bit of panic as this has been the first major problem I’ve had with my tube equipment. So I powered everything off and decided to start with the preamp. Logical starting point since I could hear the volume and nothing else had changed in the amplifier it was feeding. 

Removing the Doge 8 Cover

Immediately the problem was obvious. You could see the 3 tubes that had the white haze all over the plates. I removed the tubes and put the stock tubes back in to make sure that was the only problem in the chain. Luckily no damage had been done to the preamp by the tubes becoming microphonic.

First 3 tubes Microphonic
Triplett 3444 Testing Siemens ECC82

I feel like I really dodged a bullet. I haven’t had this happen yet and no components of the preamp were damaged so I feel very lucky. While tubes can go bad there are a few things to remember. Cheap tubes sometimes mean cheap tubes. You know the ole “you get what you pay for” saying. Buy from a dealer that is known for quality tubes, tests the tubes, and shows results for those tests.

Every set I’ve gotten from VTubeAudio has come with a sheet showing the results of the test for each tube. It’s seriously awesome to know what they read before you put them into your tube equipment. It’s peace of mind and will save frustration when you are listening to your music.

Test Results Sent With Tubes

I’ll be patient next time. I should have waited for the right quad of 12AT7 to come along. I feel like everyone has a story of an amp being affected by tubes going bad. I would love to hear your experiences with tubes that didn’t live up to your expectations, and then catch up on past posts by clicking below.

For Shure – The end of an era

For Shure – The end of an era

If you love tubes there is a good chance that you like vinyl as well. I fall into this category. I have been an Audio Technica cartridge fan since I first got into vinyl. I talk about getting into vinyl in my last post to the right.

Audio Technica AT95E

I like the sound of the Audio technical carts, one reason was because it was the first step up in cartridges that I purchased. It was the Audio Technica AT95E and was a HUGE leap from the cartridge that came with the turntable I had at the time.

Since then I have stayed with Audio Technica cartridges. Currently, I am using an AT440MLB and it is an amazing cartridge. It brings out detail that isn’t heard in some cartridges, but it doesn’t come that way out of the box.

Audio Technica AT440MLB

The cartridge right out of the box can be very bright sounding. The highs can be very forward. These carts are known to be tilted up in the highs. There is a solution though. It’s called cartridge loading and it can take a cartridge like the AT440MLB and completely flatten the frequency curve out. Then all of a sudden you have an unbelievable cartridge that tracks like a beast and zero inner groove distortion.

Lesbox MK3 Cartridge Loading
Loading Kit
Final Cartridge Load
Resistor and Male RCA Plug

On my second turntable, I use a Shure M97XE. I originally purchased it because I read it was a warmer cartridge that could hide flaws in vinyl and tracked pretty good. When I received the cartridge I wasn’t disappointed. Nice mid range, solid lows, and the highs were a bit more rolled off than I like normally.

Rolled highs are an okay trade-off for being able to play some of the vinyl in the discount bins at local shops. Currently, it is installed on my Technics SL-1700 MKII and they match perfectly!

Technics SL1700 MKII
Jico SAS N97XE

I’ve had plans of replacing it with the Jico SAS stylus that everyone raves about, but I just can’t bring myself to spend the money on it. I like the cartridge enough the way it is but I do think there are better cartridges out there, but not for around the $100 price tag that the M97XE was when I purchased it.

The Jico SAS stylus is supposed to make it a real giant killer in terms of cost vs performance. That is a good thing since Shure is no longer making phono cartridges and replacement N97XE stylus will be harder and harder to come by. I really hate to see a company stop making anything that is related to Vinyl. Shure never really seemed to evolve with the market though. They did not have a high-end cartridge that could really dig deep into a record and bring out details like some of the other big names. Shure just seemed fine making DJ cartridges and the M97XE. The M97XE was a good cartridge, but it doesn’t really get into the Hi-Fi realm of cartridges. For me saying goodbye to Shure as a phono cartridge maker isn’t really that big of a deal.

Catch up on past posts below