Petrus tube amplifier

Details: Written by: Grzegorz Makarewicz; Category: Tube equipment; Last Updated: 15 December 2025; Hits: 1002

Grzegorz "gsmok" Makarewicz, This email address is being protected from spambots. You need JavaScript enabled to view it.

The tube amplifier called "Petrus" is manufactured by a small factory in Ukraine. I do not know the number of units produced - it is certainly small - but this did not prevent at least a few units of this amplifier from functioning in the environment of our domestic fans of tube sound. They enjoy quite a good reputation. The amplifier is based on 6S33S tubes (so-called "devils") operating in class A and allowing to achieve an output power of about 15W per channel.

The amplifier is placed in two independent housings. The upper one houses the amplifier's actual circuit, while the lower one houses the power supply. Both amplifier blocks are connected to each other using four solid cables. Let's start with a few shots of the "complete" device, i.e. connected into one whole.

The amplifier looks very solid. How solid - I was convinced of how solid - when I tried to put it in the right place to take a photo. It turned out that lifting it is basically impossible for a person who does not train to lift weights. I performed all the activities related to moving the amplifier by separating the power supply and moving both blocks separately. The amplifier itself is not too heavy - all the transformers are located in the power supply housing. Yes, yes, that's not a mistake - there are also speaker transformers there. Unlike the "bare" amplifier block, the power supply box (plus speaker transformers) put my spine to a hard test. I think it weighs over 30kg!!!

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Time for a gradual vivisection of the amplifier. Here it is on the workbench - a view from the back - still with the cables connecting the amplifier to the power supply...

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