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Pabluetick
Junior Member
Username: Pabluetick

Post Number: 12
Registered: 3-2005
Posted on Tuesday, November 14, 2006 - 10:46 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

I recently got an Amp Supply La 1000 NT.. It uses 6mj6 or 6lq6 tubes. It needs re-tubed.. Where can a guy find these tubes without needing a loan to afford them ?? I remember buying 6lq6's for 6 bucks each back in the 70's.. I'm sure not gonna pay more for the tubes than the amp is worth...
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Kid_vicious
Senior Member
Username: Kid_vicious

Post Number: 2266
Registered: 9-2004
Posted on Tuesday, November 14, 2006 - 9:21 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

the following is a quote from *ham product reviews:
"I want to make one more important point. A lot of amateurs who own old Swan and similar sweep-tubed-finals gear often substitute these tubes as if they were the same tube. They are not. One will not necessarily operate in place of the other. When I say operate, I mean satisfactorily.

Replacing a 6KD6, with a 6MJ6 will work, but the IMD goes through the roof. Since most folks who do this, don't have the proper equipment to check for spurious emissions, they assume everything is working correctly. It isn't.

Some folks take great delight in rebuilding old tube gear, and that's good. But replacing an old electrolytic with a more modern constructed unit is one thing, but finals are a different animal altogether."

as for the tubes, you're not going to find them much cheaper than you see on ebay.
they are out of production and going up in price every day.
these days a sweep tube amp is worth as much as the tubes that are in it.
you may be able to re wire it to accept EL509's which are the tubes being used in the KLV amps.
they are about 25.00 each these days.

this is the reason my sweep tube amp just sits and collects dust.
one day i hope to salvage the chassis and the transformer, and build my own amp using transmitter tubes.

good luck with your amp.
BTW, the 6MJ6 is a heavier duty replacement for the 6LQ6. 6JE6 can be used but is the lightest duty of the bunch.
matt
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Copake12516
New member
Username: Copake12516

Post Number: 9
Registered: 6-2006
Posted on Wednesday, November 22, 2006 - 10:04 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

The 6MJ6/6LQ6 beam power pentode/sweep tube
uses a 9QL configured base. It is directly replacable with the following tubes:
6JE6C, 6ME6, 6LZ6, 6JE6A, 6JE6B, 6JE6
6JF6, 6JU6, 6KM6.
I have been in the tube radio/tv repair biz for years and have used these as replacements in radios, tv's, linear amplifiers and transmitters without any problems at all. Most folks who have these sub tubes don't realize that these will sub and they even look exactly the same to boot. So you can get them at very cheap prices if you look around for them. As stated above, I have yet to have any problems subbing out these tubes in many different applications as long as they are 9QL based tubes.
If anyone else has any information that doesn't agree with mine, please let me know as I would like to see what you have done and why.
Thanks,
Copake12516
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Onelasttime
New member
Username: Onelasttime

Post Number: 6
Registered: 8-2011
Posted on Sunday, August 07, 2011 - 4:53 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

I have been looking at these alternatives myself because of prices and such. What I wondering though is how it affects power output. Many of these sub's vary from 17,20,24 watt's dissipation but the 6MJ6 and 6LQ6 where 30watt rated.

Am I correct in thinking that if a tube has 1/2 the dissipation rating then another tube it will like wise put out 1/2 as much output power given the same input power?

I have also looked into EL509 but to be honest they are just as expensive now. I am sure at one point they where cheap before all the middle men realized how much the older alternatives cost. A single 6LQ6/6MJ6 euns about $69 each and about $149 for a matched pair. The Svetlana EL 509 NOVAR base model is $75 each and $160 for a matched pair so the EL509 assuming you get the correct one and not the JJ509 or other's that are not Novar base are not much of a saving today.

The only real advantage wouldbe that it would be easy to stock up on them in NEW condition instead of NOS or used. At some point maybe we will all need to make the switch but at this point I do not see where it is any type of savings? Is their some place that sells Svetlana EL 509 tubes at a cheaper price then the $75-$77 price I have seen online?

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