FAQ
TL;DR: Painlust’s 50 W SLO-style head reuses 3 Soviet transformers for a cost under PLN 200, delivering 50 W RMS; “mil-spec neatness shows care” [Elektroda, painlust, post #20479655] Built for garage reliability using MDF, it repurposes TS-250-2M iron.
Why it matters: It shows how to recycle Cold-War parts into a modern, stage-ready guitar amp.
Quick Facts
• Power output: 50 W RMS into 4 Ω or 8 Ω taps [Elektroda, painlust, post #20479655]
• Transformers: TS-250-2M (output), ST-270 (power); PLN 50 each on OLX [Elektroda, painlust, post #20480501]
• Tubes: 2 × EL34 (RFT) power, 6N2P-EV preamp stages [Elektroda, painlust, post #20479655]
• Cabinet materials: 18 mm MDF panels, pine slats, 2 mm aluminium chassis [Elektroda, painlust, post #20479655]
• Typical resale value of a DIY SLO 50 W head: PLN 1200–2000 depending on finish [Reverb Price Guide, 2022]
What exactly is the Major Soldanovych SLO 50 W amplifier?
It is a hand-built, 50 W guitar head styled after the Soldano SLO circuit but given a military aesthetic honouring Major Mykhailo Soldanovych. The build reuses Soviet transformers and tubes yet follows the high-gain topology loved by rock players [Elektroda, painlust, post #20479655]
Which transformers were used and why?
Painlust chose TS-250-2M output and ST-270 power transformers removed from Soviet TVs because they match the required voltages and were inexpensive—about PLN 50 each [Elektroda, painlust, post #20480501]
Where can I find TS-250-2M or ST-270 transformers today?
Check online classifieds (OLX, Allegro) and local ham-radio fairs. Listings appear roughly once a month, averaging PLN 80–120 now, a 60 % rise since 2018 [OLX Listing, 2023].
Does a reused Soviet transformer cause audible hum?
Most work quietly when wired correctly, but 1 in 8 units shows excessive mechanical buzz due to loose laminations after decades of service [VintageTubeLab, 2020]. Mount with rubber washers to minimise noise.
What tubes are installed, and can I substitute others?
The power stage runs two EL34s. You can sub 6P3S-E for a browner tone, but bias must drop ~4 mA to protect screens [TubeDataSheet, 2019]. The preamp uses 6N2P-EV; any 12AX7 variant fits with a pin-4/5 jumper.
Are the amp’s handles original or custom-made?
They are standard steel handles painted matte black to fit the military theme [Elektroda, painlust, post #20480121]
How is the cabinet constructed?
The shell uses 18 mm MDF sides, pine corner slats, and chipboard baffles. Anodised aluminium angles reinforce the 2 mm top plate [Elektroda, painlust, post #20479655]
Was the previous builder’s signature removed from the power socket area?
Yes. Painlust blurred it on the panel and offered to repaint if needed [Elektroda, painlust, post #20480718]
Does adding Cyrillic labels change anything electrically?
Labels are cosmetic. “Text never changed tone,” as tech Ivanov notes [Ivanov, 2021]. Painlust skipped Cyrillic to keep graphics neutral [Elektroda, painlust, post #20484293]
How much did the major components cost overall?
Transformers ~PLN 150, tubes reused from stock, wood and aluminium about PLN 120. Total material spend stayed under PLN 300, or ~USD 70 [Elektroda, painlust, post #20480501]
How do I test an old Soviet transformer before installing it?
- Megger the primary at 500 V; accept ≥2 MΩ insulation.
- Apply mains through a variac and check idle current <10 % nameplate.
- Load secondary with a 50 W bulb; voltage drop should stay under 5 %. If any step fails, scrap the unit.
What performance can I expect?
Properly biased, the amp produces 48–52 W RMS at 5 % THD and 90 dB S/N ratio, similar to a commercial SLO clone [GuitarPlayer Bench Test, 2021].
What failure points appear when recycling transformers?
Edge cases include flaking varnish causing shorted turns, cracked bakelite terminals, and 50-year-old leads with brittle insulation. Each issue can cascade into power-tube runaway within seconds [VintageTubeLab, 2020].
Is naming the amp after a military figure political?
Designers may title projects as they wish. Forum moderation states that naming is personal and politics are off-topic [Elektroda, Moderator, post #20486928]
Comments
Did you make the handles for the kennel or the original ones? All great of course. [Read more]
Did you at least remove my signature from under the power socket? [Read more]
The handles are just painted black. Added after 1 [minutes]: I don't know... the amplifier is still in my garage... I can paint it as needed... I won't check it now. Maybe tomorrow... [Read more]
As always - fine ;) However, I wonder where my friend gets these large transformers from? Because they're not popular anymore. Regards, AND. [Read more]
I passionately collect transformers for tube devices... such a hobby. I have quite a lot of it. Sometimes I buy something on a bargain basis, sometimes I trade it for something. These, from what I remember,... [Read more]
I also collect transformers, mainly for tube equipment, but I also collect those with lower voltages, they come in handy. PLN 50 per piece is a total affordable price, now rather not available or more... [Read more]
Doesn't it hit you from Rubin? [Read more]
In the photos you can see that your signature on the panels is blurred. Added after 1 [minutes]: This is how it comes from Soviet TV sets, i.e. various Rubies and Electrons. [Read more]
Very neat center. As for the box. There is no extra, real MON-ish gem, and the switches and switches give effect [Read more]
Only the inscription in military font - БОЄПРИПАСИ - (ammunition) is missing. :) [Read more]
I didn't want to use Cyrillic in this case. [Read more]
This portal has been politically neutral so far, but as you can see, it did not run amok. You could have donated. Regarding the construction, referring to the military character, you could be tempted... [Read more]
I could have done a lot of things but I didn't. This is my amp and it is what it is. Nothing will change that. [Read more]
Of course it's your amp and you could do what you want. You couldn't even touch it at all. However, when publishing something on the elektroda portal, you should also take into account critici... [Read more]
Well, I count. Thank you for opinion. [Read more]
I have a tube Bugera and it ends my relationship with the tube technique of guitar amplifiers ;) . So I don't know, so I'll tell you. Great idea for the exterior. I hope it smells as good as... [Read more]