Russian Tubes you can use in Guitar Amplifiers
When most people use the term "Russian Tubes" they usually think of Electro-Harmonix, Sovtek, Tungsol, all those familiar brand names that have been floating around the tube/valve amp guitar scene for years. Another name some people may not have heard of is Reflektor. Sovtek tubes are produced in the Reflektor factory, but there are still millions of tubes around with the Reflecktor logo on them. In this post I am going to cover some of the Russian tubes that I have bought over the last three or four years and use in guitar amplifiers.
Is it a Tube or a Valve?
Well that depends on where you live. in the United Kingdom, we have always called them Valves. In the States they are vacuum tubes, or tubes. In the Eastern Block they call them Bulbs. Tube is a more accurate name so I will refer to them as tubes.
Most of the tubes I have bought over the last few years are not well known to the average musician, but if set up properly they can work just as well as the more popular tubes used in most guitar amplifiers over the last 60 years.
Buying Russian Tubes
Just a note. Someone on a Facebook post left a comment saying Russian tubes suck. This comment was based on his political stance of the Government in Russia. I replied to the comment asking for his facts on why Russian tubes suck has he put it. He replied saying, why buy tubes from a Communist state. and he also asked me if I had ever lived under Communist rule. That statement had nothing to do with the quality of the tubes. I pointed out to him that when you buy Russian tubes you are buying them from the people, small businesses. This puts bread on their table. I have bought most of my Russian tubes from a Guy in the Ukraine. Putting bread on that Guy's table made me feel much better than buying tubes from rich companies in the Uk and United States. Russian tubes are good. I have used them for several years. Why can't we all just stop fighting and get on with each other?
Let us check out some Russian Tubes
I have made a list below of some of the tubes I have in my stash. The photos have been taken in low light. I did this because I found that the logo on the tube shows up much better. If you look at the tube name, you can see that it is in Russian. It can a bit tricky at first translating to English.
6F5P Triode Pentode Tube
6F5P is a Triode and a Pentode in one bottle. I bought these recently, but I have not had the chance to try them in a guitar amplifer project. The Pentode has a dissipation of 9 watts. g2 has a dissipation of 2 watts. The triode has a mu of 70, which is the same as a 12AT7 (ECC81). The plate voltage is rated at 300 volts. Grid 2 is rated at 250 volts. The date on these tubes is 04/1974.
The 6F5P is often touted as being identical to an ECL85 tube. However, this tube is not identical, although the pin out is the same. The ECL85 has a dissipation of 7 watts and g2 is 1.5 watts. This tube be would okay as an equivalent if it were biased at 7 watts to match the effective load resistance for the output transformer.
6P15P Pentode Tube
6P15P is an output Pentode tube. It has a dissipation of 12 Watts. g2 dissipation is 1,5 watts. The maximum plate voltage is 300 volts. The maximum g2 voltage is 200 volts. I have done a fair bit of testing with this tube. If you put much more than 200 volts on g2 it will begin to run away. The logo on these is not clear. I bought these as slightly used. You could use this tube as a substitute or an EL84 in low voltage applications and providing you can set the g2 voltage to 200 volts. The pinout is almost the same. You must wire pin 6 (g3) to pin 3 (cathode). Pin 6 and pin 3 are wired together inside an EL84 tube. 6P15P is not the same as an EL84.
6P15P is seen online as an equivalent to the EL83 tube. These two tubes are not the same. The pin out is different for a start. The EL83 has a dissipation of 9 watts. There is a Chinese version of 6P15P called SV83. Could this be the Russian version re-badged?
6P6S Pentode Tube
6P6S is a 6V6 equivalent. It works well and is cheap to buy compared to most 6V6 brands. I have used 6P6S extensively. I pushed over 300 volts into the plate and g2 with no problems. The plates are rated at 350 volts and g2 is rated at 33 volts. On the datasheet they claim 13.2 watts dissipation. You can see the Reflektor tube box in the picture. I love these old boxes. The tube pictured has a date of 11/1974.
6P18P Pentode Tube
6P18P is touted as being an equivalent to EL82. It has a dissipation of 12 watts. EL82 has a dissipation of 9 watts. g2 on both tubes has a dissipation of 2.5watts. If you are wiring these cathode bias and you are looking for 100% dissipation, then these tubes are not the same. 6P18P will substitute for EL82 but not the other way round. I have pushed the plate voltage to 300 volts with no problems. It is best to keep g2 voltage at 250 volts or below. I balanced up a pair of these in a Wem Dominator MK3 guitar amplifier and they worked fine. These tubes are super cheap to buy.
6P1PEV Pentode Tube
6P1PEV is really good tube. i is listed on the internet as an equivalent of the 6AQ5 tube (EL90). This is not the case in my opinion. Why? Well for a start, 6AQ5 is a 7 pin tube; we have a 9 pin tube here. They both have similar specs but I don't see how you can call a tube equivalent if it fits in to a different tube base.
I have pushed 6P1PEV up to 300 volts plate with no problems. Best to keep the g2 voltage at 250 volts.
You could use in place of an EL84 but you would have to rewire the tube base and possibly increase the dropping resistor to g2 to lower it's voltage to 250 volts. You would also have to re-bias the amp, even if the amp is Cathode Biased.
6P43PE Pentode Tube
Now here we have the lesser spotted 6P43P. The first thing you notice about this tube when you fire it up is that there is a distinct drop in volume compared to other tubes in it's class. This is because it has a lower mu. Some might quickly jump to say that the lack of volume as not much use, think again. Years ago everybody wanted loud guitar amps. But in the now that is not the case. If you are doing small pub gigs and you want to crank the volume up on your amp to get that sound, then you need a low wattage amp. Or an output tube that you can crank with a bit less gain. This tube could prove to a hidden gem.
I have done some testing with this tube, but I need to to some further tests. I will post the results here when I have done so. 300 volts on the plate but don't exceed the 250 volts on g2.
6P3S Pentode Tube
6P3S looks like a 6V6 but is far from it. It's closer to a 5881 tube. The dissipation of a 6V6GC is 30 watts. A 5881 is 23 watts. Our Russian counterpart is only 20.5 watts. The plate and g2 voltage is 250 volts, but people have pushed limits much further than that. Biased correctly these will will substitute for 5881, though you will loose a bit of volume. But they are fairly cheap tubes. They won't replace a 6V6GC, and although they look the same, they are not the same.
6J8 Pentode Tube
6J8 is a HF Pentode. It is a 6SJ7 equivalent. I bought a few of these but I have not managed to find the time to test them and I have not used them in any projects. If you are working on late 40s and early 50 guitar amplifiers this tube is well worth checking out. A lot of early guitar amp designs used the 6SL7. Some of the cinema projector amplifiers from the 50s had the 6SL7. Many of these amps have been converted in to guitar amps.
Conclusions and Summary
These are probably the best pick from the Relektor factory tubes to use in guitar amps. The advantages are, they are cheap compared to the more common tubes used in guitar amps. These tubes are great as long as you get the voltages right on the plate and g2.
I have put a couple links below to some videos on my YouTube channels These Wem Dominators have been fitted with Reflektor factory tubes. I go through process of making these tubes work. Some of the plate voltages have been pushed a bit and time will tell if it shortens the life of the tubes. That said if you only get a couple of years out of them, they are cheap to replace. There must have been a time when someone pondered on how long an EL84 would last putting an extra 100 volts on the plates. We now know they last a good few years despite extra voltage added to them.
Wem Dominator Mk3 Restoration Master Volume Channel Mod and Experiment with 6P51P and 6P43P Tubes