djoliverm
New Head-Fier
- Joined
- Jul 26, 2016
- Posts
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Hey guys! So I bought this guy on Amazon and I immediately wanted to replace those stock Chinese "6J9" tubes. What I could find online was that the 12AX7 tubes would fit and work for this particular hybrid tube headphone amp, so I went ahead and ordered a set of Tung-Sol Gold 12AX7's, and when I got them and put theme in, immediately you get a high pitched squeal, which has nothing to do with the volume that he amp is set at (i.e., at "zero" it's just as loud as at any other volume"). I used an FFT on my phone and the it seems that the peak of this sound was around 1800Hz, and also tapered off at other higher frequencies. Here is a screenshot of that.
Thinking that they were defective, and not finding anything online about this particular problem, I returned them for a refund, and ordered a pair of JJ 12AX7's, which are the number one seller on Amazon. Tried these just now and the same exact thing happened. I've tried swapping their positions, and putting them in individually on each of the two sockets, same deal. The stock Chinese tubes however work fine.
Now, I know the 12AX7 are the highest gain of their family, so is there something to them just not really working for headphone amps, and should only really be used for guitar amps? I've read reviews for all of these tubes where people use them in other headphone amps, so it appeared to me that at least in some headphone applications they do indeed work.
I'm just wondering if anybody else has had success with swapping out better tubes on this particular amp. I would greatly appreciate any help, thank you!
Thinking that they were defective, and not finding anything online about this particular problem, I returned them for a refund, and ordered a pair of JJ 12AX7's, which are the number one seller on Amazon. Tried these just now and the same exact thing happened. I've tried swapping their positions, and putting them in individually on each of the two sockets, same deal. The stock Chinese tubes however work fine.
Now, I know the 12AX7 are the highest gain of their family, so is there something to them just not really working for headphone amps, and should only really be used for guitar amps? I've read reviews for all of these tubes where people use them in other headphone amps, so it appeared to me that at least in some headphone applications they do indeed work.
I'm just wondering if anybody else has had success with swapping out better tubes on this particular amp. I would greatly appreciate any help, thank you!