Recommendation for replacement tubes?

fishbones · July 2010

Hey guys,
First time poster here. Been lurking for a few weeks and have learned a ton on this forum already - and I haven't even asked a question yet (well, til now). There is alot of knowledge on here so I thought you guys would be the ones to ask. Just getting back into this obsessive and expensive hobby after a long hiatus. Had to feed other expensive hobbies first (saltwater fishing), and the wife can only take one at a time...understandably.

I have a Cary SLP-30 preamp. It is making some excessive and intermittent tube noises (crackling/sizzling through the speakers more than normal) and feel they probably need replacing? I know nothing about tubes, except that this unit is pretty nice sounding. It has 3 tubes: (1) 6CA4 rectifier, (2) 12AU7 line stage. I bought it new about 15 years ago and have never replaced them. I didn't know if replacing the same type (if they still make them) was the best idea, or if there is something better within a reasonable price? Nor, where to purchase them? Thoughts and/or experiences???

Thanks for the help...

inspiredsports · July 2010

Has the preamp been used heavily over the 15 year time period you mention. If so, it is probably time for new tubes. If not thre could be other components causing problems.

Before you replace, you might find this helpful: I like the write-ups about various tube families at audiotubes.com (no afilliation) and his AU7 page is at http://www.audiotubes.com/12au7.htm.

I was recently shopping 12AU7's by accident (I thought an amp I ordered needed them, but it actually uses 12AT7's). They seem to be in high demand, and I'm not sure what your budget is, but triple mica black plates in one of the quality brands are worth shooting for.

RCA "cleartops" also seem to have a good reputation and there were some available on eBay if you search there for "rca 12au7 cleartop".

F1nut · July 2010

You need new tubes. What brands are in the preamp now?

zingo · July 2010

http://thetubestore.com/goldlionecc82.html

http://thetubestore.com/ehx6ca4.html

inspiredsports · July 2010

One of the links I saw lead to EH tube as a low-cost suggestion. When I received it my pre had (new) matched Electro-Harmonix tubes installed, and they are a great low cost choice if the cost is your single criterion, but I think they have a harsh sounding edge to them. Replacing them with better quality NOS tubes made a dramatic difference in my pre.

I think your pre (and ears) would appreciate better grade tubes.:)

decal · July 2010

15 years on the same tubes?You don't listen to a lot of music do you?Give Paul Lindemann a shout at chowbeardog@sbcglobal.net.He will steer you in the right direction for some NOS tubes.No relation to me,I'm just a very satisfied customer.

fishbones · July 2010

Thanks for the great responses already!

Here is some answers:
Tube of 6CA4 says: NATIONAL GOLD
Tubes of 12AU7 is RCA (HG underneath)

Other answers...I am resurrecting some of my 2-channel system. Got into HT/Music combo system for some years due to the family friendliness, but was never very pleased with the sound. The Cary has been boxed up for about 10 years (whew time flies by). First 5 years was under hard use, and was making these noises in the 4th year. I just switched the left/right channel tubes (12AU7) to see if the sound switches sides (Cary tech suggestion). It's intermittent...so I'm waiting.

Price range I guess depends on how much sonic improvement there is. $100 would be acceptable, unless of course the seas parted for ones that were $150-$200, the of course, being who I am, I would have to have it!

fishbones · July 2010

Okay, so last night after posting my question, a new sound started in my right speaker (the original post was about the left channel). Now in the right channel, a different sound - a gurgling/spitting sound like forcing music through a blown driver (actually cuts the music out while its spitting, whereas the original sound didn't cut any of the music out) It's not a blown driver on the speaker - it does it through all the drivers on the speaker. It goes away if I switch the Cary unit on-off, but comes back whenever it wants.
I switched inputs to make sure it wasn't with that - it did the same thing. After switching the tubes left/right channels it stayed in the right channel - didn't move. The original sound "tube noise" in the left channel hasn't come up again yet, so don't know if the switch will move that to the other channel yet or not?

I also have a set of White Audio Lab Q75 double-chassis monoblocks that one side is fried on. This happened way back when, and I just let it be cause I was switching to HT rig - still not sure what to do with these? I thought this HiFi (or MidFi) stuff would last in quality, but both were problematic after 4-5 yrs? Oh well, we have a ton (I mean A TON) of lightning here in SW Florida (We're either ranked 1st or 2nd highest lightning strikes in the country), so it might have gotten some surges - though I was pretty religeous about unplugging - I can't say I was perfect.

F1nut · July 2010

You need to try some new tubes. I would stop playing it until you do.

There's a lot of tube sellers, here's a few.

http://www.audiotubes.com/audtube.htm

http://www.tubedepot.com/

http://thetubestore.com/

https://www.tubeworld.com/index_high.htm

http://www.kcanostubes.com/

fishbones · July 2010

After some closer looking, my RCA tubes are actually 12AU7-A (owners manual says 12AU7). Can I get 12AU7, or do I need to stick with 12AU7-A?
Here is a pic of what I have:

doctor r · July 2010

Any of the 12AU7 designated tubes are all fine with or without the "-A".
Since you do not seem interested in "tube rolling" based on the duration that this set of tubes has served you I would go to one of the above listed tube sellers for a quality well tested set as apposed to an uknown source or the one I like to deal with Andy at Vintage Tube Services

http://vintagetubeservices.com

Best to actually call him (he likes to discuss your situation and is ultra slow on e-mail), tell him the equipment you have and he will do you well. Might cost a couple of dollars more but you will forget about any tube changes for many more years. Navigate through the website it is interesting.
Hope this helps
Rick

Recommendation for replacement tubes?

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