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R&R tubes in Transcendent T8-LN

68.104.110.35
Posted on November 30, 2019 at 17:34:59
LtMandella
 I needed to replace one of the EL-509 power tubes in my Transcendent OTL (no complaints I bought the unit in 2001) and since I have a collection of 30-40 "NOS" (LOL) tubes I started to replace them all.

However I am finding that the plate cap rubber/plastic sleeves that grip the cap onto the tube anode are crumbling/rotting and will no longer grip.

So I ordered batch of 16 1/4" ceramic replacement caps from AES.

I can solder the replacement caps onto their respective connecting wires no problem, but anyone have additional advice for tube replacement effort?

thanks,
LT

 

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RE: R&R tubes in Transcendent T8-LN, posted on December 3, 2019 at 06:13:58
rogerh113
Audiophile

Posts: 506
Location: San Francisco South Bay
Joined: October 20, 2014
 There were some posts on cleaning and tightening the tube sockets. If you are in there, it might be a useful thing to do.

You will need to do a search to find the posts.

 

RE: R&R tubes in Transcendent T8-LN, posted on December 3, 2019 at 08:45:01
Lew
Audiophile

Posts: 10911
Location: Bethesda, Maryland
Joined: December 11, 2000
 I share Roger's concern for the tube sockets. If you've been using the amplifier regularly since 2001, and if the anode caps are obviously degraded, then I would be concerned that the sockets could be degraded as well, from the high heat. Probably worthwhile to check them and clean them and also make sure the solder joints to the pins are still solid.

 

RE: R&R tubes in Transcendent T8-LN, posted on December 3, 2019 at 10:11:52
LtMandella
 Thanks guys

I will at least deoxit and pipe cleaner the sockets.

And I will try and get a look at the sockets and solder joint - depending on how much disassembly of the chassis may be required.

There are a couple techs in Vegas where I live that work with tube amps.
But I expect it would end up being 5 hours at $100 per hour to R&R the tubes, replace the anode caps, and rebias. Which if I was working I would gladly pay - the amp is worth it that's for sure. But I am not working so it's all on me.

 

RE: R&R tubes in Transcendent T8-LN, posted on December 4, 2019 at 06:09:22
rogerh113
Audiophile

Posts: 506
Location: San Francisco South Bay
Joined: October 20, 2014
 Do you have any soldering skills? Replacing the ceramic caps is pretty easy stuff.

I think these amps were also sold as kits, so instructions should be around. The only important thing is to make sure the electrolytic caps are fully discharged before you go in there - not a hard thing but important.

 

RE: R&R tubes in Transcendent T8-LN, posted on December 4, 2019 at 06:40:34
LtMandella
 yes I should have no problem with the soldering (famous last words :).

And actually I bought the amp new, "Factory" assembled directly from Transcendent Sound.

I did post on the Transcendent forum but haven't heard anything from there. I expect that group really expects a 20 year old amp to need some maintenance and the owner to be able to do it...

 

RE: R&R tubes in Transcendent T8-LN, posted on January 1, 2020 at 07:35:09
LtMandella
 All fixed! Amp sounds great again.

I replaced the anode caps with ceramic versions.

Replaced 8 EL-509 power tubes with tubes from my "NOS" cache.

Then I decided to take a look on the component side of the board and found 4 leaky 1 mfd 630v caps, so replaced those.

After all above replacements, still not much improvement. Sound was thin and distorted in the lower frequencies.

As a last resort, I decided to check the fuses. The T8-LN has a 1.5 amp fuse for each channel, and a 6 amp power fuse.

Since I always had sound from both channels I never thought to check for an open fuse.

But one of the channel fuses was open. After replacing that fuse, all is good!

 

There's obviously nothing wrong with you,..., posted on January 20, 2020 at 13:03:22
Lew
Audiophile

Posts: 10911
Location: Bethesda, Maryland
Joined: December 11, 2000
 because you DID have something wrong.

Any idea why a blown fuse didn't cause profound problems, apparently since you only found it by checking fuses?

 

RE: There's obviously nothing wrong with you,..., posted on January 20, 2020 at 14:25:53
LtMandella
 Well kind of depends on your definition of "profound".

There was basically no bass, and even the mids were distorted.

I don't understand electronic theory well enough to know the function of the circuit that was fused. I would have expected one channel to be completely dead.

But it was not.

The amp is a factory built T8-LN from Transcendent Sound. I have the schematic...

 

RE: There's obviously nothing wrong with you,..., posted on January 20, 2020 at 14:51:15
LtMandella
 also it might be worth noting: visually there was little indication the fuse was blown - it is one of 3 for the amp. No glass discoloration or burn mark. But continuity test showed it was open.

 

RE: R&R tubes in Transcendent T8-LN, posted on January 20, 2020 at 15:21:15
LtMandella
 I gave them a pipe cleaner cleaning but did not try anything more.

I was concerned I might do more harm than good...

 

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