Grzegorz 'gsmok' Makarewicz

The mid-range tube amplifier. The traditional solution arrangement with nonconventional possibility to switch between triode and pentode mode. The information appearing in many places that it is an amplifier with autobias that doesn't require adjusting the quiescent current of output tubes  encouraged me to publish a short description and not as a short set of photographs of this device. This is not true that amplifier has autobiasing. I warn users of the amplifier before carefree approach to this important issue.

I'm breaking with the convention of placing the order of equipment photos. Usually the first picture shows a general view of the amplifier, and photos of the construction details appear later. This time as the first image a photograph on which the amplifier is in the middle of  adjusting quiescent currents after replacing the output tubes procedure is shown.

Now back to the beginning, or photos from the overview to the details of construction. Beautiful views. The amplifier is really well-made, it has a good design. I found it only one drawback - too short cables connecting the main board and the output transformers, which makes some maintenance work - but it's really nothing.

You can find several varieties of this amplifier model with different housing (the version with elements of wood - really nice) and equipment (gain control and input selector). Presented model is the "poorest" version. Technical specifications are common to all versions.

Technical specification

Tubes EL34×4, 12AX7×1, 6SN7GT×2
Output power 2×18W (Triode mode), 2×40W (Pentode mode)
THD 0.2%
Frequency bandwidth 10Hz - 70kHz
SNR 89dB
Input voltage 400mV
Input impedance 50K
Output impedance 4 i 8 omów
Power consumption <300W
Dimensions 356 (W) x 321 (L) x 197 (H) mm
Weight 18.5kg

Opracowanie: Grzegorz 'gsmok' Makarewicz