While it looks nicely built, the fact that none of the power supply cabling has been twisted is somewhat surprising.

It's not an amplifier that would interest me, but it probably sounds very good. All the info is there for you to make a decision!

Description

Tube power amplifier DIY handmade.

Spare Tubes New available. Construction drawings and description available.
This amplifier was made by a hobby builder and technician first class.
I'm switching to monoblocks made by the same builder.

All info except about the technique via marketplace.
I only respond to serious interest.
Payment by bank transfer or cash.
Not a tap on apps and will not be sent for reasons you also know, weight and fragility.

EL130 Power Amplifier DIY Description:

The amplifier is equipped with 4 pieces of E130L power tubes that are parallel 2 by 2. These tubes are in class A at a supply voltage of approximately 170V. The power tubes are connected to a special stereo output transformer. This actually consists of 2 single ended transformers, but they are wound on the same core.

Each channel also has a single E80F as a steerer tube.
The steering tubes are controlled from a filter print.

The filter ensures that the low tones of both the left and right channels are combined and sent to both control tubes. The mid and high tones of each channel are sent only to the corresponding channel. For the low tones, however, the amplifier functions as a mono bass amplifier, with the transformer in fact acting as a balance transformer. For the middle and high tones as a stereo amplifier, with the transformer in fact as 2 single ended transformers.

The power supply consists of 2 toroidal transformers for the high voltage and 2 toroidal transformers for the filament voltage of the power tubes.
The filaments of the control tubes are supplied with direct current and form part of the cathode resistors of the power tubes.

The amplifier supplies a maximum of 20W per channel for the middle and high signal. For the bass, the amplifier delivers a maximum of 2x25W (50W mono).

The bandwidth (-3dB) runs from 20Hz to 50kHz. The distortion is <0.5% anywhere between 30Hz and 20kHz.

The outputs of the amplifier are switched on with a delay to block start-up sounds.

Clearly based on the E130L pentode. I think it's either a kit or a home build by somebody very knowledgeable and capable. I don't think I've ever seen a commercially made E130L amp. Likely the seller doesn't have a clue about it, maybe a deceased estate sale, who knows. If you take it on, you may have a whole lot of sorting to do. But I bet it could be a very worthwhile project for somebody.