Tube Rolling w/Crack

[attmci]

3.5 A. So yes, a 6080 (2.5A) with ECC31 (0.95A) will work.

With the 5998 you're safe.

The PT-3 power transformer can handle 3.5 amps of AC heating.

Not sure about the PT-10.

[attmci]

Another safe bet is the 6H13C Svetlana's sold on Ebay.
Does look the better and sounds great.

Buying tubes is mostly like a box of cookies.

I am not a fan of that tube. And no way it can beat a TS 6080wb carbon plates.

[attmci]

The postage is going to cost more than the tube itself.
Not sure if they sell 6080wb

Give them a call. They may still sell 5998 tube too at reasonable price.

[ianp]

I finished the stock build in a couple of evenings and have been listening to the stock crack for 5 days now and it was time for some tube swapping.

I had a couple of 12AU7A (Electro-Harmonix and a CONN clear top) tubes in the cupboard and they sound a little better than the stock on my 650s. Listening to the CONN now. It seems add a bit more clarity, a nice sense of airiness to the top end and seems to dig a little deeper for some of the details, but this may be at a little cost to the bass. Ahh, the joys of tube rolling, what you gain on the swings you sometimes lose on the roundabouts 

VALABS pot goes in next and then I'll have to buy a speedball and then look some more into tube rolling.

[Lawrence Ho]

Give them a call. They may still sell 5998 tube too at reasonable price.

They don't have any 5998 for over a year.
And it is unlikely they will in short time.

[Lawrence Ho]

guys, I won a WE421a auction on ebay lately.
The seller provided a photo of the testing result. I think it is about 70% strong but in terms of hours, how many do I have before replacement is needed?
Any input would be appreciated!

http://www.ebay.com/itm/421A-Western-Electric-Domino-Plate-Side-to-Side-Balance-5998-7236-6080-6AS7-/182545442144?nma=true&si=KgsMuS5i2jzuPaOLr4d69ar2XUk%253D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557

PIC: http://imgur.com/a/ZD3QX

[Lawrence Ho]

I finished the stock build in a couple of evenings and have been listening to the stock crack for 5 days now and it was time for some tube swapping.

I had a couple of 12AU7A (Electro-Harmonix and a CONN clear top) tubes in the cupboard and they sound a little better than the stock on my 650s. Listening to the CONN now. It seems add a bit more clarity, a nice sense of airiness to the top end and seems to dig a little deeper for some of the details, but this may be at a little cost to the bass. Ahh, the joys of tube rolling, what you gain on the swings you sometimes lose on the roundabouts 

VALABS pot goes in next and then I'll have to buy a speedball and then look some more into tube rolling.

Conn 12au7 happens to be my stock tube came with the crack.
After rolling in cv4003 and mullard ecc32 over months, i still keep going back to CONN becasue of its airness and extension to the top. I do agree the comprosmise to the bass. But i am afriad there is no all round solution.

[Paul Birkeland]

guys, I won a WE421a auction on ebay lately.
The seller provided a photo of the testing result. I think it is about 70% strong but in terms of hours, how many do I have before replacement is needed?
Any input would be appreciated!

It's absolutely impossible to say.  That tube could've produced those measurements the day it was manufactured for all we know.

[Lawrence Ho]

It's absolutely impossible to say.  That tube could've produced those measurements the day it was manufactured for all we know.

The seller told me the same thing. He also said the tube is 90% strong where 4000 to 9000  hours continuous use should be fine.
I am just hoping it is true.

[Doc B.]

You pays your money and you takes your chance. That's a part of DIY. IME tube vendors can't really have any idea how long a tube will last. Particularly a used one. They can only tell you how it tests and you can try to guess what that might translate to with respect to lifetime.

[Lawrence Ho]

You pays your money and you takes your chance. That's a part of DIY. IME tube vendors can't really have any idea how long a tube will last. Particularly a used one. They can only tell you how it tests and you can try to guess what that might translate to with respect to lifetime.

Apparently i have mistaken the readings as a reliable indicator of tubes’ health..

[Doc B.]

It's a measurement which, depending upon the type of tester, might give you an indication of a tube's transconductance or heater emission. If it measures below spec it's most likely not going to perform correctly. If it measures well it will probably perform well assuming there are no noise issues. But you don't necessarily have a measurement that relates directly to how long it will perform to spec. Lifespan specifications for tubes are generally in the thousands of hours, so a tube that measures well and sounds good is probably worth investing in if it is what you desire.

[Lawrence Ho]

It's a measurement which, depending upon the type of tester, might give you an indication of a tube's transconductance or heater emission. If it measures below spec it's most likely not going to perform correctly. If it measures well it will probably perform well assuming there are no noise issues. But you don't necessarily have a measurement that relates directly to how long it will perform to spec. Lifespan specifications for tubes are generally in the thousands of hours, so a tube that measures well and sounds good is probably worth investing in if it is what you desire.

Thanks for the explanation, doc.

My apologies being off-topic a bit, do you have plan to make the speedball upgrade switchable? Meaning that one can switch back and forth between speedball’ed and stock crack by pushing, a botton maybe?

I will get the speedball regardless. Just that i think i will miss the sound from the current crack from time to time..

[Doc B.]

We have no plan to do that.

[attmci]

They don't have any 5998 for over a year.
And it is unlikely they will in short time.

Good to know.

They were selling 5998 for $85 a couple of years ago.