I do appreciate the advice,...

Tube DIY Asylum

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Posted by Lew (A) on May 12, 2020 at 16:17:05

In Reply to: RE: I'm somewhat encouraged that the panels are OK posted by 6bq5 on May 12, 2020 at 14:21:36:

but bear in mind that I have owned the gear for several years, and in the first one or two of those years, the amplifiers were resurrected from front to back. No selenium rectifiers any longer, for example. Steve O has been a great help (and now AJ) in this lengthy process and so has Bill Thalmann of Music Technologies. By now, I cannot think of a single part in the amplifiers that has not been replaced with modern equivalents, including the tube sockets, except for the high voltage film capacitors that have a coupling function. I have some Russian made substitutes for them, should the originals need to be replaced. For the past 2-3 years, I have enjoyed trouble-free operation, until this incident with the fuse blowing. The aggravation now and then is well worth it, because the SQ is fantastic. I am pleased to learn that you also apparently have a high level of expertise with the Beveridge speaker panels, in particular. For me, that's a black box I have not yet had to open.

I don't use the built in woofer amplifier in the 2SW or even the low pass filter in the crossover. For woofers, I use KEF B139s in transmission line cabinets that I built myself, 40 years ago. I drive them with a Threshold amp via the low pass output of a Dahlquist X-over.

You mention the possible effect of arcing or the spider web on the rectifiers. I'm using modern ones rated at 7.5KV (one pair) and 10KV (the other pair). Today they test as "OL" on my Fluke 87 meter, in both directions. I consulted with Bill Thalmann on this result, earlier today. He says that is normal for the particular rectifiers I've got, meaning they can be regarded as OK.

Now you've got me worrying about running the amplifiers without a load on my work bench. Should I be? I've been doing it that way for the entire time I've owned the amplifiers.

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Follow Ups Full Thread

Topic - Can a spider web do this? - Lew 14:43:53 05/8/20 (14)

Sad to say there is something else going on. - Lew 10:38:54 05/10/20 (8)

RE: Sad to say there is something else going on. - AJ 13:57:17 05/10/20 (7)

RE: Sad to say there is something else going on. - Lew 10:18:29 05/11/20 (6)

RE: Sad to say there is something else going on. - AJ 17:28:14 05/11/20 (5)

I'm somewhat encouraged that the panels are OK - Lew 12:33:21 05/12/20 (2)

RE: I'm somewhat encouraged that the panels are OK - 6bq5 14:21:36 05/12/20 (1)

I do appreciate the advice,... - Lew 05/12/2016:17:05 05/12/20 (0)

AJ, thanks for the useful information - Lew 07:53:09 05/12/20 (1)

RE: AJ, thanks for the useful information - AJ 13:23:34 05/12/20 (0)

RE: Can a spider web do this? - AJ 07:45:37 05/10/20 (2)

RE: Can a spider web do this? - Lew 08:24:18 05/10/20 (1)

RE: Can a spider web do this? - AJ 16:12:32 05/10/20 (0)

3000 volts can do very strange thing, Yes, they can jump along a web - Chip647 14:53:23 05/8/20 (1)

You've got one too. - Lew 15:01:09 05/8/20 (0)

Follow Ups

I do appreciate the advice,... - Lew 05/12/2016:17:05 05/12/20 (0)

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