Amplifier PZT Type WR-75

Written by Grzegorz Makarewicz (gsmok), Warsaw, This email address is being protected from spambots. You need JavaScript enabled to view it..

The amplifier, which I would like to present was produced in 1962 in Warsaw, Poland. The physical evidence can be seen below in a form of the metal plate riveted to the housing.

Amongst my old tube amplifiers this one is characterized by a unique weight. It is so large and bulky that the Polish Post Office refused to send it to me in one package. Willy-nilly before shipment it had to be disassembled and placed in two packages. The choke was removed from the amplifier and along with the removable part of the metal casing was sent in a separate shipment. After this operation, some peaces of paper markers on electric wires remained in the amplifier interior- what is mentioned in the following description..

The amplifier interior is completely original (which can be compared with the description of the same amplifier with some slight adjustments).

So here is the amplifier's view in all it's glory.

A metal casing is painted of so called "hammer lacquer". On all knobs someone (read: vandal) painted lines, probably to help assess the location of the sliders of potentiometers. I tried to remove these "artistic extras" but I could not. After many years the paint is hard as steel - it does not take any solvent, and mechanical removal can cause damage to the knobs' surface - so I decided not to remowe them for the time being.

The amplifier's housing is in good condition. First of all, it is not bent or pressed in. Unfortunately it took some corrosion. Here and there appeared some paint chips. This is especially true in places where ornaments are attached. This can be seen in the photo below.

Manufacturer of the amplifier mounted two tasteful retractable handles. Their functionality is, however, problematic. Handles are very short and the enormous weight of the amplifier effectively prevents to use them.

On the back in addition to the wall outlet, input and output jacks there is a surprise - a set of sockets enabling measurements of  voltages and currents.

Here are fuses and sockets for connecting the speaker.

Old type mains socket and a set of test sockets.

Sockets for connecting a signal source.

This is the amplifier interior after removing the cover. The cover itself is made very reliably and most importantly, is well matched to the chassis. The assembly / disassembly is smooth (for me it was a very positive surprise, when I remembered disassembling the "MELOMAN" amplifier).

View of the amplifier with tubes procession - just wonderfull.

An additional shot slightly from above. The amplifier is all dusty. Photos were made in order to document its original state (okay, I admit that I could not resist and polished one of the rectifier tubes, what you can see on the following pictures).

Now a discrete shot from behind ...

...from one side...

...and the other.

At this point I had to stop the amplifier testification because the Important Technical Inspector had arrived.

My cat named DeeDee was particularly interested in the preamp tubes.

It's time to show some details. In several photographs, I tried to capture as many details that (hopefully) can be useful for anyone who is faced with the task of restoring the amplifier of the same type.


Now is the time to the tubes gallery. Dusty but beautiful.

A pair of AZ4 rectifier tubes. Supposedly the twins but they significantly vary. Look at the difference in size. The smaller was cleared by me - I wanted to see if it is really AZ4.

Before I turned the amplifier upside down, I did this photo of the beautiful transformer.

And this is how the amplifier looks from the bottom. Wiring is a bit chaotic. For those interested in the details, I put the entire set of photos.





This choke had to be removed before shipment of the amplifier.

[updated 31.07.2005r.]

(written by Grzegorz Makarewicz (gsmok), Warsaw, This email address is being protected from spambots. You need JavaScript enabled to view it.)