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Home WS1 Copper Cap
Item Code: WS1
WS1 Copper Cap Item Code: WS1

WS1 Copper Cap

  • 8-pin Copper Cap. Diodes and Limiter only, No Sag. Vdrop: 1V max @ Imax: 1000ma

* Required Fields

Replaces any rectifier tube with solid-state rectifiers for no sag. OK to for use with HIFI tube amps, tube radios, etc. Diodes and Limiter only, No Sag. Voltage drop: 1V max at Maximum Current: 1000ma.

The WS1 is best for use in radios and stereos, since there are no resistors to create unwanted sag and unnecessary heat. As it is, it's just diodes. We can build it with a thermistor to give you a few seconds of warm-up, which some amps without a standby switch could benefit from. If you want the special WS1, just choose it in the drop-down menu.

Technical Details


To install the Copper Cap rectifier, simply remove the existing rectifier and replace it with the Copper Cap. Make sure the tube rectifier is cooled down before you remove it.


The WS1 is a solid state rectifier that fits into a standard octal rectifier tube socket. They are built with diodes for rectification and have no sag. This model also has no inrush current limiting. The envelopes are solid hard-drawn copper with a high thermal capacitance that allows a 100% continuous overload condition.

Why use a Copper Cap?
The Copper Cap emulates a tube rectifier, but it does not require filament power. In the case of a 5U4, for instance, this is a savings of 15 watts. The power transformer will run cooler and last longer. While the filament and coating on the cathode of a tube rectifier are destined to eventual failure, a Copper Cap will last the lifetime of the amp when used properly. Additionally, close tolerance parts are used in all Copper Cap models; no hand sorting is necessary.

How does the Copper Cap work?
It is a combination of diodes, power resistors, and other circuitry that emulate the warm-up and operating curve of the tube type rectifier it replaces.

Are the Copper Caps drop-in replacements or do I need to make changes in the wiring?
All octal-based Copper Caps are drop-in replacements. Because they don't require filament power, the 5 volt filament source may be either left connected as is or disconnected and used for some other purpose.

Can I use this WS1 Copper Cap in an amp that doesn't have a standby switch?
No, there is no inrush current limiter on the WS1.

What about the peak currents that occur when the filters are in the charging cycle?
The combination of the conservative power rating of the Copper Cap and the high thermal capacity of the copper envelope prevent any stress problems from transient power pulses, etc. Plus, all Copper Cap models are rated for 100% overload.

Do I have to do anything special to use a Copper Caps?
The octal-based Copper Caps are about twice as heavy as a standard glass-envelope vacuum tube, so you should ensure the tensioning on the rectifier socket in your amp is correct, particularly in the case of Fender amps where the tube hangs upside down. No other precautions need be taken other than to make sure you give it plenty of time to cool down as you would a tube before removing it.

What are the PIV ratings of a Copper Cap?
The WS1 rated at 2,000 PIV.

Customer Reviews of WS1 Copper Cap

4 hi-fi use


January 06,2018
4 hi-fi use

It is small, but I followed the recommendation on the site. Is in a tube stereo amp, 60 watts per channel. Seems to work fine, no issues. Took a little extra effort to seat in the socket than the 5ar4 did.