12BH7A Question

[skidave]

I asked my wife to buy me some 12BH7's for Christmas and she came through (I supplied a few websites that sell them and she picked one). So I replaced my JJ ECC82 with a matched pair of 12BH7. Yuck, they are noisy and have a lot of microphonics. They are a pair of Ei tubes and I think I want my money back. I called to ask if this amount of microphonics is normal and the guy said I can return them and pay an additional $8 to have a matched pair with 'low' microphonics sent to me.

My ECC82 are dead quite and have no microphonics that I can hear. I was excited to try the 12BH7s because of the positive comments about them being a great preamp tube.

Anyone have any input...

Thanks,

Dave

[zippy1540]

i've replaced the 12au7 in my diyst35 and there seems to be a world of diference, cleaner sounding with a deeper image, pared with a 5751 the image is leaps and bounds above the 12au7/12ax7 combo
sounds like it might be the circut design

[erichayes]

Hi All,

My experiences with EI tubes leads me to believe that the Yugoslavian equivalent of "Product Uniformity" doesn't exist in their language. Some of the best, and some of the worst sounding tubes I've heard have been EIs, and you never know which way they're going to go. For a while, EI was the only source for new production 12BH7s and 6CG7s. When Universal Audio reissued their LA-2A compressor/expander, their production supervisor told me they were having a Hell of a time getting 12BH7s that were consistantly worth a damn.

A little over a year ago, New Sensor came out with their 12BH7 EH. I got a few and was pleasantly surprised. Their curves aren't quite the same as NOS RCAs, but sample to sample uniformity looks quite good and microphony doesn't seem to be a problem.

They're available with steel or gold plated pins (those of you who are familiar with my opinions and foibles know how I feel about gold clad anything in audio) from www.newsensor.com with the steel pin version going for around $20.00.

No, I'm not employed by Mike Matthews.

[WA4SWJ]

Gang,

I've been using NOS RCA's with no problem. Got them from that auction Web site. You may also be able to find them at local hamfests relatively inexpensively. I've also using ElectroHarmonix 12BH7's that seem to work fine. I'm listening to a couple of those right now.

Regards,

[Blackburn Audio]

I have used the 12BH7's with good success and no problems with microphonics but I have always used NOS. Just popped one in a DIY35 with a blackplate 5751 combo and it sounded great although I think I prefer the 5965 for the PI. I just got this thing built over the weekend so I'll have to do some more swapping and see what I like best. If you do need some good quality 12BH7's shoot me an email and I'll make sure you get some that sound good without microphonic problems.


-Matt at Triodeelectronics.com