Totally Tubular: The Tube Thread

kvetcha said:
I discovered the variable output runs at too low of a signal level for my SVS to pick up, so I wired the Jolida through the high level speaker inputs instead and spent a little while getting the crossover and gain sorted. I have bass again!
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That actually makes sense as the JoLida is essentially a power amp with a volume control and a selector switch.
 
Any of you lovely folks have any experience with tube corrosion? I've got what looks like some greenish buildup along the bases of a couple of my 6550 power tubes, near where the base meets the glass. Doesn't seem to be affecting anything at the moment, but these things are $40/pop so if there's anything I can do to fix it or prevent it from spreading, that would be great.
 
kvetcha said:
Any of you lovely folks have any experience with tube corrosion? I've got what looks like some greenish buildup along the bases of a couple of my 6550 power tubes, near where the base meets the glass. Doesn't seem to be affecting anything at the moment, but these things are $40/pop so if there's anything I can do to fix it or prevent it from spreading, that would be great.
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Interesting.. too much moisture in your listening space maybe?
 
HiFi Guy said:
A few things I look for:

As you said, lenient return policy.

When researching a piece of equipment, I look for the bad comments, if you can find them. They tend to be a bit more honest. There are a few pieces/brands that that have no bad comments that I can find- Sutherland phono stages are a good example.

Look at the context too. Someone who bought a Grado cartridge did complains that it hums? That's not a cartridge fault. That's someone that doesn't understand why this can happen or what turntables will be incompatible. Twenty years ago, this was excusable. Not now. The info is out there and easily located.

In some instances, you may find better value with brands that sell factory direct. Zu, Audio by Van Alstine (AVA) and Decware come immediately to mind.
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Decware makes beautiful sounding and excellent build quality gear IMO
 
I haven't run my amp in triode mode for a long time, so today I got a wild hair and decided to spend some time with it in triode. I forgot what a good impact it has on the top end and spatial cues. The trade off is still giving up some bass impact, but it's still pretty satisfying. I might run it like this for a few days and then switch back and see how I feel.
 
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Well, it's been over a week and now I think I happen to have time on Saturday to put some time in doing an A/B with the triode and pentode mode again.

I'm going to plan to put together 5-10 songs that I have on both vinyl and digital/streaming, with a preference to stuff I have on CD. Should be a fun day!
In the mean time, I've just been getting more and more curious about the Devore line of speaker. I still haven't been able to get ears on them yet :(
 
After a much shorter than expected triode/pentode shootout, it looks like I'll be focusing my speaker hunt on higher efficiency speakers. 90db will be my minimum, as that's where my JBLs sit with 6ohm load. Devore looks even more appealing on paper now, but you just never know until you get ears on things.
 
Random question. What do people do with their tubes when they reach the end of their lives?

It seems like they shouldn’t be something that goes for landfill/incineration as: 1. they have lots of recyclable component materials; and 2. they contain toxic material.

I struggle to find any info on recycling/safe disposal so am wondering if you knowledgeable lot can provide me with any illumination!
 
Joe Mac said:
Random question. What do people do with their tubes when they reach the end of their lives?

It seems like they shouldn’t be something that goes for landfill/incineration as: 1. they have lots of recyclable component materials; and 2. they contain toxic material.

I struggle to find any info on recycling/safe disposal so am wondering if you knowledgeable lot can provide me with any illumination!
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I put known bad tubes out with the garbage.
 
So here's an interesting update for those who have PrimaLuna amps or may be interested.

Last week after I went to bed, the amp dropped a channel. My wife was watching a movie so she turned the amp off and used TV sound. A bad tube indicator had illuminated. She forgot to tell me.

The next night when I came home, I turned on the amp and headed to the record room to select an album. I heard a horrible "brrzzaap" from the system and rushed out to see a bad tube light for the left channel.

I changed the tube. All of the tubes lit up on powering the amp again, but I had no output on the left channel. I verified it was an amp issue by checking with headphones as well.

It turns out that the tube suffered a catastrophic failure and blew the fuse on the left channel for Adaptive Auto Bias board.

After speaking with my wife she said that the bad tube light she experienced was for a different tube than the one that went out on me. So it looks like the Tung Sol 7581A doesn't have great longevity. They lasted 7 months under very heavy use. I expected a couple of years out of them.

To replace the fuse, I lugged to amp back to the bedroom with the tube cover on and laid it on the bed with the bottom of the amp facing upward. The Dialogue HP has two Adaptive Bias boards, one for each channel. After removing the bottom plate, the fuse holders are easily located. The boards are are on each side of the chassis. The left channel board is on the right (because you are viewing the amp from the bottom up.) I used a small flathead screwdriver (the same one I use for cartridge installation) to prise the top off of the fuse holder. I replaced the fuse and buttoned everything up. I saw no evidence of any other damage.

Then I pulled out the original set of Prima Luna EL34s that came with the amp and installed them. Everything works beautifully.

I'm not a fan of the factory tubes. I have an octet of Genelex Gold Lion KT88s on the way along with a pair of Gold Lion 12AU7 input tubes.

I am convinced that the Prima Luna Adaptive Auto Bias circuit is brilliant. I've personally seen catastrophic tube failures cause additional damage along with a blown fuse in other brands. Not so with PrimaLuna. A mild tube failure wouldn't have blown the fuse, which is what my wife experienced. No noise, just the light. A catastrophic failure will blow the fuse.

The difference between an HP with 8 tubes and a non HP with 4 besides power: the HP amps have two Adaptive Autobias boards- one for each channel. A non HP has only one board. So if a fuse blows on an HP, one channel will still work. A non HP won't put out sound at all if the fuse blows.

Fifteen months in, I'm still thrilled with my PrimaLuna amp.
 
Yesterday I spent about 5 hours with a system using the Musical Paradise MP-D2 MK3 Deluxe DAC. A tube DAC that comes in at $1000 or under $2000 when built to the maximum spec from the factory. The unit we used had the ESS dac chips, and upgraded aftermarket tubes, unsure on the models.

I have to say this DAC is just so smooth. It was constantly the last thing we were thinking about. If anyone is ever looking to mix some tubes with their digital chain, I simply cannot recommend these enough.
 
displayname said:
Yesterday I spent about 5 hours with a system using the Musical Paradise MP-D2 MK3 Deluxe DAC. A tube DAC that comes in at $1000 or under $2000 when built to the maximum spec from the factory. The unit we used had the ESS dac chips, and upgraded aftermarket tubes, unsure on the models.

I have to say this DAC is just so smooth. It was constantly the last thing we were thinking about. If anyone is ever looking to mix some tubes with their digital chain, I simply cannot recommend these enough.
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Looks like it is discontinued.

The Denafrips DACs look interesting, but not tubed. I may up my DAC game next year and actually fire up the Mac Mini.
 
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