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OLDER DECWARE GEAR SUPPORT >> SE84A, SE84B, SE84C, SE84C+,SE84CKC >> troubling arc in rectifier tube???
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Message started by ski bum on 09/24/09 at 23:45:53

Title: troubling arc in rectifier tube???
Post by ski bum on 09/24/09 at 23:45:53

I'm currently using the stubby Russian 5Y3GT rectifiers in my zens, and I've noticed an arc or flash coming from them during warmup (ususally within 2-3 mins of turning the unit on, not immediately). Should they be doing this? Are they about to fail? Do I need to worry about this? Everything seems to be working properly. Anyone have feedback?

Also, I have a pair of the taller, Chinese made 5U4G's on standby if needed. Anyone have a guess on if/how these would affect performance? (SE84C+ w/ CCE mod, fyi)

Title: Re: troubling arc in rectifier tube???
Post by ski bum on 10/01/09 at 17:20:25

No news is good news?

Since I am not experiencing and performance deficits, I guess I won't worry about the mysterious arcing.

Now back to the music.

Title: Re: troubling arc in rectifier tube???
Post by Rivieraranch on 10/03/09 at 03:31:53

Why are you using Russian and Chinese rectifiers? An old American brand, even a used one would cost only a few dollars and would sound a helluvalot better than the Sino/Russian makes. An RCA 5Y3GT or a Sylvania 5U4GB would be fine. If you wanted to go all out you could score a Bendix 6106, or a GE 6087, both indirectly heated, which is easier on the tubes at startup and very good on the sound.

Title: Re: troubling arc in rectifier tube???
Post by ski bum on 10/05/09 at 20:46:32

Hola Riv-

"Why are you using Russian and Chinese rectifiers?" Only because that is what Steve had for sale; the Sovtek 5Y3GT's were the stock tubes, the other just to have as a backup. Since I have two zens, I just swapped the rectifier in one to see if I can hear a difference between the ones I currently have...

Would you care to qualify that "very good on the sound" comment? Admitted tube-noob here, just curious how rectifiers would affect things since all they're doing is rectification. I can't imagine anything but very subtle differences which may not be discernable on my hodge-podge system, but I haven't actually experimented (aside from right now, that is).

Based on recent experience with mega-buck setups this weekend at RMAF, my system with ruskie/red rectifiers is not lacking for performance by any means (a very pleasant realization, considering how inexpensive my system is).

Title: Re: troubling arc in rectifier tube???
Post by ski bum on 10/05/09 at 21:39:59

Hmm. Seat of the pants, completely subjective impression here...after just a few minutes of listening, I think I like the Chinese 5U4G better than the Russian 5Y3GT. Music from that amp just seems less restrained, more real. Wonder why this is. Am I imagining things? Is my subconsious playing tricks with me?

I gotta say, tube amps are just way too fun!

Title: Re: troubling arc in rectifier tube???
Post by Rivieraranch on 10/06/09 at 02:56:56

Each rectifier type will make the amp sound different. Steve has written as much in the manuals. Don't believe me as to the change in sound by experimenting with different brands and constructions of rectifier. There are lots of threads in here and elsewhere as to the sometimes profound difference in sound from switching a rectifier tube.

Title: Re: troubling arc in rectifier tube???
Post by ski bum on 12/20/09 at 19:17:56

Riv or anyone still listening-

What's the benefit of buying NOS? Is the vintage stuff really worth the asking price? I can find brand new rectifiers for mere fractions of the cost of the old RCA's, for example.

Also, on a related note, feedback from a more experienced tube jockey:
5Y3GT: probably not the best for hi-fi, good for guitar amp, lacks the headroom of 5U4/5AR4 types
5U4G/GB: directly heated, best for SETs; higher B+ than 5Y3GT thus sounds louder; airy, transparent, dynamic
5AR4: indirectly heated, more warm/veiled/colored/fatter bass, better for pp amps

Is this guy on the money or are these generalizations incorrect? Also, it seems that differences in class of tubes is more relevant than when the tube was manufactured, unless standards have plummeted. Please advise, oh wise interwebs!

Title: Re: troubling arc in rectifier tube???
Post by Rivieraranch on 12/20/09 at 21:54:28

He is spot on. You don't have to buy new rectifiers. You can buy used. You should really consider contacting Jim McShane, a reputable tube dealer or one of the other folks who is recognized as being in that category.

I have a few NOS 5U4GB's laying around here. They have all been tested.

By the way, I have gone to 5U4GB's from 5Y3's in all my DECWARE gear.