|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
69.159.199.148
I needed new tubes for my SP-9, it takes a couple of 6922's for the phono stage only, so it's not a big deal to change them out. I normally get them from any Audio Research dealer but the one locally didn't respond to email and has an answering machine that I didn't leave a message with.I figured it was time to try a different supplier, and Tube Depot seems to have a great reputation for quality supply and service. In any event, I ordered a pair of NOS Amperex Holland ECC88/JDJ8 with a slight extra charge for matched and balanced triodes.
The tubes were absolutely awful. As soon as they were installed, with any amount of volume there's a very noticeable hissing sound from both speakers, even when the preamp isn't set to Phono. The sound seemed to be OK, but with the hissing business I yanked them right away.
I did eventually contact the local Audio Research dealer and bought a couple of the AR tubes. As you might expect, they work fine.
I guess the question is, did I miss something or should I have let the tubes burn-in for a while. I can't see how that would eliminate the hiss, and I sure didn't want to damage the preamp.
I didn't really feel like I could go back to Tube Depot, unless the hissing sound could be considered in some way defective. As an electrical designer, I concluded it was simply a mismatch that would never work.
In any event, if the tubes won't work, they're up for grabs for anyone who wants them. The only consideration is that you let this forum know they work out for you.
Follow Ups:
At the suggestion of fellow inmates, I sent the following email to Tube Depot:
Dear Tube Depot,
The tubes I purchased with order number XXXXX did not work with my preamp. See the message thread from Audio Asylum below.
http://www.audioasylum.com/audio/tubes/messages/191304.html
It was suggested that due to the very light use the tubes have had, that it might be possible to exchange or return them for something that would be more suitable for my Audio Research SP-9 preamp.
If there is anything that can be done, please let me know. If not, I'll chalk it up to experience and specify the need for more suitable tubes the next time.
Regards,
StephenIn about 1 minute later, I received a response from Tube Depot offering me an exchange on the tubes that I had purchased, with a bit of a restock charge, more than fair considering they are long past the warranty period. Thanks to all for the advice and support, and to Tube Depot for their support.
Your experience mirrors mine with Tube Depot. I've always been satisfied doing business with them.
...it takes a couple of 6922's for the phono stage only...That's not correct. The line stage, centrally located on the PCB, uses one tube and the phono section to the right uses the other. Both stages also use some JFETs.
As for your issue, did your old tubes hiss like that? I'm happy with a pair of Electro Harmonix EH-6922s that are dead quiet. Spend twenty bucks on some new tubes and see if the fault lies with the Amperex tubes or your unit. Then you may have some leverage to swap them back to Tube Depot.
The tubes I eventually bought from the local AR dealer worked perfectly "right out of the box." Thank you very much for explaining why the hiss was apparent on both channels even when Phono was not selected.
That would explain why he has hiss even when phono is not selected. I had no idea there was only the one tube in the phono. Not familiar with this unit and assumed it used one per channel in the phono. There must be several JFET's in the signal path.
StephenJK,I have several used Amperex white label and A-frame ECC88/6DJ8 and a couple were noisy upon receipt. It was odd- the sound was fantastic, rich and deep yet dynamic but against a background of prominent hiss. I could tell the sound was excellent "through" the noise. This is the same effect when kistening to recordings of Caruso- it's possible to hear the sound quality through the noise.
Tube Depot is as company I've never dealt with, but I'm sure they will at least listen to an argument for return and refund, or perhaps they would give you credit towards tubes tested for noise and selected for phono use.
As far as I know, the SP9 doesn't put a lot of stress on it's tubes and 6DJ8s should work fine (as opposed to having to use the higher rated 6922 or 7308), but they do need to be very quiet.
Cheers,
Phono tubes must be rigorously tested and specifically selected for low noise for best results. And this goes double or tripple if we're talking about MC phono sections. There is SO much amplification of the signal going on that even the slightest bit of tube noise can come out the other end sounding like a roaring ocean. If the Tube Depot did not specifically state that they were phono quality and you did not specify that they needed to be phono quality, then you very likely did not get phono quality. Do you have any other non-phono uses for them? If yes, chances are they'll sound okay in lower gain appliactions.
Good point, as I mentioned I was hesitant to go back to them. They still list that tube on their web site, and there's no mention of being suitable for a phono stage.The SP-9 is the only tube equipment I have, so the Amperex Holland tubes will likely never be used.
I note the Tube Depot does offer the type as ‘low noise and microphonics’ as well as ‘matched and balanced’. Have a word with the Tube Depot and see if they might exchange. After all, the tube is presented as used, and the use you have made surely is but negligible. Talk to them, you’ll never know what might be accommodated until you do.I have bought ECC88 and E88CC from them, for line stage amplification and transformer-coupled output stage of DAC, and found the examples offered, Tesla in both cases, as matched and balanced, excellent examples.
I should have mentioned that the Tesla ECC88s and E88CCs were NOS.
I'm glad you specified that your tubes were NOS Teslas and not JJ Teslas, because I bought a pair of JJ 6922's from Jim McShane, and when used in my preamp the JJ's are very hissy/noisy. I should mention that with normal listening through speakers the noise isn't a problem, but because of my living arrangments I've been forced to listen to my Quicksilver Mini-Mites through headphones, and it's under those conditions that the JJ's noise has become objectionable. I should also mention that when I run my Amperex 6922 PQ's or my Phillips JAN 6922's in my preamp very little noise comes through my headphones, so it's definitely the JJ's that are the source of the noise.
Thanks for the advice, I just may do that. The tubes had about 2 minutes of operational time. If I strike out, I'll throw them up for grabs....
I have purchased tubes from Tube Depot for my AI L2. I purchased
Sovtek matched pairs and specified low noise. They were very low noise. Worked great. In regards to JJ's---you need to specify
low noise for preamp. If not, you can get noisy tubes. If they
come noisy---send them back. But low noise must be specified.;
I learned after the fact that even low-noise JJ's are known to be noisy, so there's not much I can do about it. In spite of the noise the JJ's do sound pretty good though.
This post is made possible by the generous support of people like you and our sponsors: