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MUST .... NOT .... ORDER
http://maplifiers.net/forum/viewtopic.php?f=7&t=2336		 Page 2 of 3
Author:  Devtron [ Tue Feb 21, 2012 9:00 pm ]
Post subject:  Re: MUST .... NOT .... ORDER
I might grab one of those Copper Caps. They seem pretty cool.
Author:  chris_d [ Tue Feb 21, 2012 9:15 pm ]
Post subject:  Re: MUST .... NOT .... ORDER
When i first got into maps, it was over at 18w.com, and the folks over there had a huge bitchfight with Ted Weber, so they would always talk smack about the copper caps, and how they should be avoided, but now that i know a bit more, i don't see any particularly good reason to avoid them.

If anything, they are actually a bit safer for an amp than my current solution which is just SS diodes mounted to a tube base. The Weber thing has two things going for it over that technique: 1. It is designed to provide a similar voltage drop to the tube that each specific one is meant to replace. and 2. It has inrush protection so that it operates similar to a tube recto, in that, it doesn't just let 100% of the B+ voltage blast into the power tubes on power-on, but rather holds the blast and more slowly ramps up to full operating voltage. This is technically best practices for protecting the longevity of the power tubes.
Author:  Devtron [ Tue Feb 21, 2012 9:19 pm ]
Post subject:  Re: MUST .... NOT .... ORDER
chris_d wrote:
When i first got into maps, it was over at 18w.com, and the folks over there had a huge bitchfight with Ted Weber, so they would always talk smack about the copper caps, and how they should be avoided, but now that i know a bit more, i don't see any particularly good reason to avoid them.

If anything, they are actually a bit safer for an amp than my current solution which is just SS diodes mounted to a tube base. The Weber thing has two things going for it over that technique: 1. It is designed to provide a similar voltage drop to the tube that each specific one is meant to replace. and 2. It has inrush protection so that it operates similar to a tube recto, in that, it doesn't just let 100% of the B+ voltage blast into the power tubes on power-on, but rather holds the blast and more slowly ramps up to full operating voltage. This is technically best practices for protecting the longevity of the power tubes.



I read the first run of the copper caps fukt some amps up which may have something to do with the 18w.com thing, but he has redesigned them and I have read a lot of positive stuff.

I got basically the same impression from them, a SS recto that emulates tube sag. Also, less maintenance and no tube swapping, and they are cheap.
Author:  chris_d [ Tue Feb 21, 2012 9:20 pm ]
Post subject:  Re: MUST .... NOT .... ORDER
It is worth noting though, that they are still solid state rectifiers. I personally do not find GZ34s to be very tube rectifier-y anyhow, and i don't generally prefer tubes there anyhow, so i personally would go SS any day(and indeed, that is what my amp has in it now).

If it was an amp with a super saggy recto like a 5U4 or something, it wouldn't be a great choice maybe.

That said, at lower volumes, you are not likely to get much recto sag from most amps anyhow, and beyond that, a GZ34 doesn't sag much compared top other tube types anyhow. :idk:
Author:  knope [ Tue Feb 21, 2012 9:43 pm ]
Post subject:  Re: MUST .... NOT .... ORDER
Wasn't the problem with the CC's that the Standby switch was designed poorly? Something about the tube rec not particularly liking having its heater voltage without its B+?

IIRC, I check how the standby switch was on the kitty just to make sure it wasn't like the CC's

PS: If what I remember is correct, then if you just leave the standby switch all the time you should have no problem with the tube rec.
Author:  Snaxocaster [ Tue Feb 21, 2012 11:07 pm ]
Post subject:  Re: MUST .... NOT .... ORDER
chris_d wrote:
Holyshit, the pricing on those fucking things looks to have gone a bit sideways. :red:

In light of that, i would say, maybe something like this instead: http://thetubestore.com/5ar4.html

Just be prepared for it to shit the bed at some point. I think the last one i had went about five or six months? That was at four or five hours full tilt minimum a day, four or five days a week, though.


I've had a JJ in mine for a good two years plus now. It hasn't taken near the level of abuse Chris was giving his though as I'm not slamming the amp to within an inch of its life at all times.
Author:  Unstrung [ Wed Feb 22, 2012 9:06 am ]
Post subject:  Re: MUST .... NOT .... ORDER
I dreamt that a fictional room mate had a suspicious relationship with a fictional science teacher, and they'd have keyboard and guitar into Vox jams in the garage.

They frowned upon my presence, and wished for me and my strat to gtfo.
Author:  Zozobra [ Thu Feb 23, 2012 9:06 am ]
Post subject:  Re: MUST .... NOT .... ORDER
Snaxocaster wrote:
The reliability issue with the CCs was, IIRC, 'cause of the shitty Sovtek rectifier tube. Replace immediately with a real GZ34- IIRC the Sovteks are a Russian tube that's vaguely similar-but-not-quite, and they don't take what the AC-series dishes out.


The problem was that it has a standby switch and standby switches and tube rectos do not got on as tube rectos really dont like inrush current. By letting the heaters warm before switching into play you allow the recto to supply full voltage and current. The problem is that the power tubes are also warm and will pull a huge inrush current as the caps charge when set to play. By not using standby the voltage rises gradually as the recto gets up to temperature and also the power tubes pull little current too as an unheated tube effectively is out of the circuit and presents no load so everything has a nice happy time.
Author:  Devtron [ Thu Feb 23, 2012 10:44 am ]
Post subject:  Re: MUST .... NOT .... ORDER
Zozobra wrote:
Snaxocaster wrote:
The reliability issue with the CCs was, IIRC, 'cause of the shitty Sovtek rectifier tube. Replace immediately with a real GZ34- IIRC the Sovteks are a Russian tube that's vaguely similar-but-not-quite, and they don't take what the AC-series dishes out.


The problem was that it has a standby switch and standby switches and tube rectos do not got on as tube rectos really dont like inrush current. By letting the heaters warm before switching into play you allow the recto to supply full voltage and current. The problem is that the power tubes are also warm and will pull a huge inrush current as the caps charge when set to play. By not using standby the voltage rises gradually as the recto gets up to temperature and also the power tubes pull little current too as an unheated tube effectively is out of the circuit and presents no load so everything has a nice happy time.



So, avoid the standby and switch to a SS recto tube?
Author:  Zozobra [ Thu Feb 23, 2012 12:40 pm ]
Post subject:  Re: MUST .... NOT .... ORDER
Keep the tube recto by all means but dont use the standby switch. The old vox amps never had them after all.
Author:  Devtron [ Thu Feb 23, 2012 2:02 pm ]
Post subject:  Re: MUST .... NOT .... ORDER
Zozobra wrote:
Keep the tube recto by all means but dont use the standby switch. The old vox amps never had them after all.



Eh, I might switch to a SS recto after the tube one shits out, maybe one of the Weber C-Caps which emulate the very little sag GZ34s have anywho. But good to know about the standby switch. Shit I barely let my amps warm up that much anyway ... (I are terrible mapper).
Author:  chris_d [ Thu Feb 23, 2012 2:29 pm ]
Post subject:  Re: MUST .... NOT .... ORDER
I generally don't let my amp warm up either. I just turn it on. When it is ready, it will make noise. And my amp is just straight up ss recto, and with very little inrush current limiting at all. I can afford to be lax though, if it breaks, i will just fix or rebuild. :lol:

There is definitely a bit of a gap between "what is likely to happen", and "what could possibly happen".

For instance, running a Sovtek not-really-a-GZ34 tube rectifier, is LIKELY to destroy your power tubes more quickly if it is providing more voltage than the circuit is designed for. Just a matter of time, more or less.

But, turning on an SS recto tube amp with no inrush protection will POSSIBLY result in a catastrophic over current situation. Not guaranteed, just possible.

It is also worth noting that my amp is just a pair of 6V6s. The situation gets a little trickier with four EL34s or KT88s or something, as the potential current pull increases quite a bit, and the price of the components involved also goes up enough to make cheap inrush insurance much more of a good idea.
Author:  Devtron [ Thu Feb 23, 2012 3:26 pm ]
Post subject:  Re: MUST .... NOT .... ORDER
So basically .... this amp is going to explode at some point in time.
Author:  chris_d [ Thu Feb 23, 2012 3:27 pm ]
Post subject:  Re: MUST .... NOT .... ORDER
All amps will.


If you are doing it right.
Author:  chris_d [ Thu Feb 23, 2012 3:33 pm ]
Post subject:  Re: MUST .... NOT .... ORDER
But in seriousity, if you go with a tube recto, go with a proper GZ34 like the Shuguang one i poasted. And don't use the Vox's standby.

If you go SS recto, get something like the GZ34 version copper cap, it has an inrush limiter in it(so essentially is behaves like a tube for that), and also has resistors and shit innit to provide a GZ34-like voltage drop for the right operating voltages in a GZ34 circuit. And don't use the standby on the Vox.
Author:  Devtron [ Thu Feb 23, 2012 3:43 pm ]
Post subject:  Re: MUST .... NOT .... ORDER
chris_d wrote:
All amps will.


If you are doing it right.



:lol:


chris_d wrote:
But in seriousity, if you go with a tube recto, go with a proper GZ34 like the Shuguang one i poasted. And don't use the Vox's standby.

If you go SS recto, get something like the GZ34 version copper cap, it has an inrush limiter in it(so essentially is behaves like a tube for that), and also has resistors and shit innit to provide a GZ34-like voltage drop for the right operating voltages in a GZ34 circuit. And don't use the standby on the Vox.



So fuck the standby, and use real GZ34s or the C-Cap for its inrush limiter.

I think I can handle that.
Author:  Broseidon [ Thu Feb 23, 2012 3:47 pm ]
Post subject:  Re: MUST .... NOT .... ORDER
Don't get them wet, don't feed them after midnight and

DON'T

USE

THE

FUCKING

STANDBY
Author:  Devtron [ Thu Feb 23, 2012 5:22 pm ]
Post subject:  Re: MUST .... NOT .... ORDER
Image
Author:  Snaxocaster [ Thu Feb 23, 2012 6:22 pm ]
Post subject:  Re: MUST .... NOT .... ORDER
I don't use the standby on mine ('90s RI) either.

When we did the shows with The Lost Patrol, their guitarist- who's something of a big-deal tech in NYC and occasionally winds up in TapeOp- looked at me in, if not abject horror, at least confusion re: my not using the standby. It's a Vox thing, I said, and something to the effect of using it actually shortens tube life 'cause it's a poorly implemented design and really shouldn't be there.
Author:  Devtron [ Thu Feb 23, 2012 6:53 pm ]
Post subject:  Re: MUST .... NOT .... ORDER
Snaxocaster wrote:
I don't use the standby on mine ('90s RI) either.

When we did the shows with The Lost Patrol, their guitarist- who's something of a big-deal tech in NYC and occasionally winds up in TapeOp- looked at me in, if not abject horror, at least confusion re: my not using the standby. It's a Vox thing, I said, and something to the effect of using it actually shortens tube life 'cause it's a poorly implemented design and really shouldn't be there.


I feel like if I didn't post on maps, I would have ended up having that Vox explode in my living room.
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