Ted Weber WZ34 Copper Top Rectifiers ? ? ?

maw4neu

Are these available in the UK ???? . . . They sound like a "must" for AC30 and Bassman owners . . . 

ICBM

I'm not sure, but they would certainly be a very good idea in any modern valve-rectified amp which has the standby switch in the wrong place, so it stresses the rectifier - like the AC30CC, Orange AD30 etc. (Although in my opinion the Orange sounds better with a plain non-valve-emulating solid-state rectifier.) The Bassman does actually have a suppressor cap upstream of the standby switch so it isn't quite as bad, and original AC30s with no standby switch don't really benefit.

As far as I know Weber do ship directly to the UK.

Cirrus

I was particularly impressed when I tried to pull the one I had out the GZ34 socket and the copper casing came away, exposing the naked components inside and leaving them connected. But that would have been around 2010, I guess.

In the end, I thought it was ok. At lower volumes there was basically no difference between it and a valve rectifier in my AC30. At higher volumes, once the power section was being pushed into compression, I thought the copper cap was slightly stiffer, which equated to a little extra tightness, and a slightly brighter sound. I preferred the GZ34, so back in it went.

RiftAmps

From experience, the Weber ones always fall apart (as mentioned above).

The Sovtek one is much more bullet proof and when I AB'd them, the voltages were the same - http://www.hotroxuk.com/solid-state-rectifier-ssr.html

ICBM

RiftAmps said:

From experience, the Weber ones always fall apart (as mentioned above).

The Sovtek one is much more bullet proof and when I AB'd them, the voltages were the same - http://www.hotroxuk.com/solid-state-rectifier-ssr.html

The Sovtek one doesn't contain any resistance though, surely… it's a plain solid-state rectifier rather than a valve-emulating one.

I haven't seen a Weber one fall apart, but presumably it's due to the glue breaking down with heat over time, since they do get hot.

MartinB

Just a thought, but I'm a bit uneasy about the choice of an un-grounded copper casing for a device handling high AC and DC voltages that lives outside the chassis of an open-backed combo.  Would that comply with any sort of safety certification?  And if they're prone to falling apart, that makes them even less appealing. 

ICBM

It is worrying, yes. If they're built with the copper can isolated from the internals that's one thing, but if they fall apart it's quite another...

ecc83

But WHY Copper? Surely the rectifiers do not need heat sinking?  And yes would not have hurt to use high temp' epoxy!

Dave.

Cirrus

Kind of amusing that when you google image search for "Weber Copper Cap", the first three results show the naked innards.

jpfamps

ecc83 said:

But WHY Copper? Surely the rectifiers do not need heat sinking?  And yes would not have hurt to use high temp' epoxy!

Dave.

The SS rectifiers don't get hot, but the series resistors emulating the resistance of a valve rectifier certainly do.

Epoxy is an excellent thermal insulator, so not the best choice.....

DJH83004

MartinB said:

Just a thought, but I'm a bit uneasy about the choice of an un-grounded copper casing for a device handling high AC and DC voltages that lives outside the chassis of an open-backed combo.  Would that comply with any sort of safety certification?  And if they're prone to falling apart, that makes them even less appealing. 

That's a very valid point Martin any extraneous metal part on a class 1 piece of equipment (which the majority of guitar amps are) should be at earth potential, An internal fault or physical damage could render the outer casing live. 

ecc83

jpfamps said:

ecc83 said:

But WHY Copper? Surely the rectifiers do not need heat sinking?  And yes would not have hurt to use high temp' epoxy!

Dave.

The SS rectifiers don't get hot, but the series resistors emulating the resistance of a valve rectifier certainly do.

Epoxy is an excellent thermal insulator, so not the best choice.....

There are thermally conducting epoxies.

Dave.

ICBM

ecc83 said:

There are thermally conducting epoxies.

How electrically isolating are they? I thought they contained metal dust as the filler.

The problem is that thermal and electrical conductivity are often related!

RiftAmps

ICBM said:

RiftAmps said:

From experience, the Weber ones always fall apart (as mentioned above).

The Sovtek one is much more bullet proof and when I AB'd them, the voltages were the same - http://www.hotroxuk.com/solid-state-rectifier-ssr.html

The Sovtek one doesn't contain any resistance though, surely… it's a plain solid-state rectifier rather than a valve-emulating one.

I haven't seen a Weber one fall apart, but presumably it's due to the glue breaking down with heat over time, since they do get hot.

Correct, no resistance in the Sovtek/TAD one, just 6 x 1N4007 in a neat little sealed unit.

ecc83

ICBM said:

ecc83 said:

There are thermally conducting epoxies.

How electrically isolating are they? I thought they contained metal dust as the filler.

The problem is that thermal and electrical conductivity are often related!

Why worry about a thin smear of epoxy when there is a big lump of un earthed copper?

Diamond iirc is an excellent conductor of heat but is an electrical insulator. Some ceramics have similar properties.

Dave (just off to check me facts!)

ecc83

Yes, diamond has the highest thermal conductivity of any known substance. It is also and insulator. So, diamond dust in an epoxy matrix. Job's a good'un.

Dave.

ICBM

ecc83 said:

Why worry about a thin smear of epoxy when there is a big lump of un earthed copper?

Because if the epoxy is conductive and is in contact with any of the internal components, then the copper can will become live at +470V or so!

ecc83 said:

Yes, diamond has the highest thermal conductivity of any known substance. It is also and insulator. So, diamond dust in an epoxy matrix. Job's a good'un.

Problem solved .