Some General Tube/Valve Amp Questions

TylerDurdenPSSC

TylerDurdenPSSC

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So I'm looking for an all-tube bass amp at the moment, but still have some questions that are probably basic knowledge to most.

1.) Can you run a 6550 in a 12ax7? Or a kt-88 in a 6550? Basically, can you re-tube with a different type of tube?

2.) How exactly do you bias a tube amp? I'm a mechanic, so I know my way around a multi-meter, but I have no idea how to actually do this. (The Eden intrigues me for this very reason. Doing it yourself saves you money, and I'm always wanting to learn a new trade.)

3.) Is there a way to actually tell how much life a tube has left? I ran across an ad for a Mesa 400+ on TB and the OP said he had it checked out top to bottom, the tech stating: "There's plenty of life left in the tubes."

4.) Are tubes similar to halogen lights in the essence that touching the glass will actually shorten there life? (The grease from your fingers affixes to the glass and cooks, hardening and ruining the glass.)

5.) I know there's a certain way to install tubes, but will they blow when installed reverse, or just not make any sound?

I apologize to all my brothers from the UK, I'm sure you were thinking "If this Guy says 'tube' one more time, I'm gonna stick one in his arse!" But that's how us Yanks are, we're able to piss you off with a smile. :d

Yes Greg, I just said 'arse' again. ;)

As always any input is welcomed/appreciated.
 
:d
Tubes me arse,they're valves mate.;)
I know ♣♣♣♣ all about working on them,I always paid someone else to do that.But I did learn it's best not to touch the tubes without clean cotton gloves on.I dont think you need to bias tubes,unless you're changing tube type,or it hasnt been done in a long time & the amp's not performing as it should.Usually,when tubes need attention,you'll usually hear it in no uncertain terms.
I think you should find a good tube amp tech,preferably he'll be at least middle aged & grew up on these things.I think TB has a list that might help.
The new Eden,or was it Markbass all tube head checks/biases all it's tubes & trouble shoots ever time ya switch it on.
The Mesa 400+ is an amazing head with gorgeous tone & loud as all ♣♣♣♣.
Good luck.Every bassist really should experience an all valve amp thru an 810 on stage at least once in their life.:)
 
TylerDurdenPSSC said:
So I'm looking for an all-tube bass amp at the moment, but still have some questions that are probably basic knowledge to most.

1.) Can you run a 6550 in a 12ax7? Or a kt-88 in a 6550? Basically, can you re-tube with a different type of tube?

2.) How exactly do you bias a tube amp? I'm a mechanic, so I know my way around a multi-meter, but I have no idea how to actually do this. (The Eden intrigues me for this very reason. Doing it yourself saves you money, and I'm always wanting to learn a new trade.)

3.) Is there a way to actually tell how much life a tube has left? I ran across an ad for a Mesa 400+ on TB and the OP said he had it checked out top to bottom, the tech stating: "There's plenty of life left in the tubes."

4.) Are tubes similar to halogen lights in the essence that touching the glass will actually shorten there life? (The grease from your fingers affixes to the glass and cooks, hardening and ruining the glass.)

5.) I know there's a certain way to install tubes, but will they blow when installed reverse, or just not make any sound?
...
Click to expand...

I'm no expert, but I know a little:
1) Some valves are completely interchangeable - I think some valves have different names in the US and the UK but are exactly the same apart from their name. But I'm sure some valves are not interchangeable - it'd be like plugging the wrong batteries in something - it might not work, it might explode, or it might be fine, but I wouldn't try it!

2) No idea, sorry.

3) I think the only answer to this is from Greg - an expert can tell the sound of a valve that's dying, and that tech reckoned those valves sounded fine.

4) Yes, I think so. They certainly get pretty hot in use!

5) I don't think you want to try this: these are electrical components and you're thinking about switching the wiring to them essentially at random? That's crazy! Again, I'd say it's like the battery thing: it might not work, it might explode, or it might be fine, but I wouldn't try it!

When you get your valve rig we'd love to hear some sound clips! Good luck with the hunt!
 
TylerDurdenPSSC said:
So I'm looking for an all-tube bass amp at the moment, but still have some questions that are probably basic knowledge to most.

1.) Can you run a 6550 in a 12ax7? Or a kt-88 in a 6550? Basically, can you re-tube with a different type of tube?

2.) How exactly do you bias a tube amp? I'm a mechanic, so I know my way around a multi-meter, but I have no idea how to actually do this. (The Eden intrigues me for this very reason. Doing it yourself saves you money, and I'm always wanting to learn a new trade.)

3.) Is there a way to actually tell how much life a tube has left? I ran across an ad for a Mesa 400+ on TB and the OP said he had it checked out top to bottom, the tech stating: "There's plenty of life left in the tubes."

4.) Are tubes similar to halogen lights in the essence that touching the glass will actually shorten there life? (The grease from your fingers affixes to the glass and cooks, hardening and ruining the glass.)

5.) I know there's a certain way to install tubes, but will they blow when installed reverse, or just not make any sound?
Click to expand...

12ax7 is a pre-amp tube
6550 and kt-88 are among the most popular power tube
and are interchangeable in a lot of amps, but not all

bias procedure differs from amp to amp, best refer to manual
the Markbass tube amp auto-bias every time it "boot-up"
the Eden E300 has the bias on the outside of the case for easy access

no idea how to tell remaining life of a power tube
perhaps those that advertise about the remaining life
just check that there are no deposit on the glass and
the fact that the tube does not glow a weird type of colour when power up ...

yes, similar to halogen lights

just follow the manual
 
Appreciate the input babebambi.

My main question was in regards to interchangeability. I've found that I'm not fond of tube amps with the 12ax7/12au7 combinations, but really like the 6550 and kt-88 setups. They just sound more "tubey" in my head.

I like the "auto-bias" feature of the markbass, but also really dig the Eden because it doesn't. (I'm a carburetor and points ignition kinda guy.)

Not to forget the Markbass and the VB-2 fall within my price range new, and a used Eden or Fender do as well... oh well, the soich continues!
 
I've found that I'm not fond of tube amps with the 12ax7/12au7 combinations, but really like the 6550 and kt-88 setups. They just sound more "tubey" in my head.
Click to expand...

I have yet to see amp that doesn't use some form of 12AX pre tube. Again, 6550's and KT88's are power tubes so are EL34's. Here's a link to buy tubes and accessories: thetubestore.com - Audio vacuum tubes for your amplifier.. I'm not sure where you are in Ohio...but this tube amp tech is in Indianapolis and comes very highly recommended. He will gladly answer most your questions over the phone: Uncle Alberts. Between the two links you should have all the info. you need to make good decisions. Hope I've helped.
 
Again, another helpful post. Methinks Ill give them a call tomorrow mornin while waiting for my Zon to arrive.
 
And thanks for the links again lilpbass, here I thought there were.many didferent types of preamp tubes, but after some quick research all I'm interested in do utilize the 12x tubes. I guess its just Ampeg amps just aren't my cup of tea all together.

New question:

1.) How do you guys feel about the kt-88 versus the 6550? I know I like the Ruby 88's in guitar amps, (The Eden as well) and the 6550's are slightly more common/affordable.

I'm tearing up that tubestore website, reading as many of these reviews as possible!
 
Ryan, I personally don't have a preference. My last tube amp used 6L6's and sounded really good. Tube amps are cool. They can be money pits...(start buying Duende Criatura tube rings) and if you have much rapped in this magical beast, you had might as well get the Bias King, to save time and money on servicing. Yeah, my OCD and bad back broke my tube addiction! It's fun and always a learning experience. I think everyone sound have one at some point, just for experience.
 
dude im really interested in this, maybe check it out? [video=youtube;Swwu2AGsgi0]https://www.youtube.com/watch?v=Swwu2AGsgi0[/video]
 
I actually have looked into that particular head, and there is actually one on TB for a primo price too. I just digure if I'm going to go with Orange, my personal only real option is the ADB. If I stick with solid state, Ill probably go with Line 6 (LowDown 750 is dowsn to $400.) and pick up an EBS ValveDrive.
 
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