I have had my P20 for a few weeks now and am currently trying out these russian sub-miniature tubes. These are 6N18B which have broadly similar characteristics to the 6N3P. These are almost identical to the more widely available 6N16B. So far I am liking the sound of them, bass is all there and...

I have the cloth pads on now and probably about 4 hours total usage. The bass is now definitely better, tightened up and allowing the mid-range to come through more. I think, as has been said previously, more burn-in will help but they are not bad at this stage, no glaring faults.

Yes, I totally agree with that. The bass is overly soft and highs lacking sparkle.

I have just used them for a couple of hours movie watching. Think the bass is getting better or maybe I am getting used to them. Comfort is great, didn't feel the weight at all. I think the soundstage is getting better too. Tomorrow I will try them with the cloth pads. I have been using a...

Yes, early days yet, but the bass bothers me the most. If you play a track with not much bass they sound very good, mid-range is clear and detailed but I would like a bit more sparkle in the highs. But anything with bass in it and it seems to overwhelm the whole sound and sounds fuzzy. I do like...

Received mine today. Just brief sound impressions as I haven't had enough time to get used to them. They sound overly warm. The bass is indistinct and the upper bass shadows the mid-range. The highs are there but not prominent so you certainly can't call these bright. Fairly detailed but...

I got the same message. The photos she sent of the HI 3050 look identical to the HF 580 and the specs are similar but not identical. Maybe some minor changes but I accepted the HI 3050 too.

Just received mine and they are as good as has been said many times before. Got them on Aliexpress from Music HuHu Store ( how do they come up with these names ?) for just over $60 after coupons and that included the carry case. Has to be the best deal at the moment.

Thanks pvico for the schematic. I measured the B+ and it was 185v not 210v. Also, the heater voltage was 11.9v so I don't know if that affects your calculation of the bias current.

Looks like you got an early one with decent components. Lots of Wimas there which aren't bad for a cheap capacitor. Can't tell what you have for the power supply bypass though.   The soldering on the tube sockets looks okay so if you are still getting noise on one channel that goes away when...

Yes, they are the ones but those in the picture are 630v. You only need 250v and they are much smaller so will fit.

If you are going to move the transformer then the case is of little use ( and you would have to lengthen all the wires ). You would be better off getting a tube amp kit off ebay. They cost very little and you can mod them any way you like and then fit a case to suit.   The input caps are there...

This amp isn't really suited to modding because of the cramped case but if you have one and want to mod it then there are benefits in changing the caps and maybe some of the resistors. This is my modded board :     I have changed the output bypass caps to 1uf Mundorf Mcaps, the coupling...

I too have some 6N23P but I don't like them that much. I find the whole 6DJ8 family too analytical and cold. This 6N16G-VIR has a similar sound to the 6N16B but more of the "magic". I don't notice raspy vocals but I am using a ( now quite modified ) LD 3 so that may be the difference. Others I...

Firstly I would like to apologise to Mordy for not replying to his PM he sent months ago. I have not been checking this forum for over a year. You may remember that I was keen on the russian sub-miniature tubes and recently I ordered some 6N16B-VR to add to my collection. When I received the...

  What you are seeing here is the effect of an unregulated power supply. The 6N6P powertubes put out about 20 ma and the 6CG7 probably less than half that so the lower current draw increases the B+ . You have it exactly right in saying the 6SN7 is a better choice than the 6SL7. I noticed on...

  This is my collection of 6CG7/6FQ7. From the left we have 2 Super Radiotron 6CG7 made in Australia, then what I think is an RCA with side getter, labelled 6CG7/6FQ7, and lastly, and probably the best, an Amperex labelled 6CG7/6FG7 , made in USA with what looks like the GE pattern of dots. I...

I have made up some 9 pin adapters so that I can run the power tubes out of their sockets and can take some measurements. So in the LD Mk111 with stock 6N6P power tubes and some Mullard EF95 driver tubes this is what I recorded.   LEFT   Heater    6.43v   Plate      105.8v   208.0v  ...

  I have been using the external power supply with a 6SN7 for a few days now. I wasn't entirely happy as there was some hum and random interference too. A bit of reading lead me to the solution. You need to tie the negative heater lead to ground. This is because when using a wall adapter there...

  The answer to all your questions is ... Yes.   The wall adapter and voltage regulator are used instead of the LD transformer. So connect the heater wires directly to the output of the voltage regulator. This way, the suspected power limitations of the LD transformer are avoided and you can...

  For 12.6 volt tubes a 9v 500ma adapter would not be sufficient. There are 'step-up' voltage regulators similar to the one I have, that will output a higher voltage than the input but with reduced current. Remember Watts = Amps x Volts so as volts increase, current decreases and vice-versa. So...

  I have made up an external power supply for the heater filaments. Just an old wall adapter I had lying around and a little voltage regulator board. These little boards can be bought on ebay for less than $5. The output voltage can be adjusted with the trimpot which is the blue block with the...

  This is something I am currently working on. I am thinking of using a wall adapter and a simple/cheap voltage regulator to bring it down to the required DC voltage. I can't see it making much difference to the sound but will get around the possible limitations of the LD transformer. Should be...

  I would simply try another tube and see what you get for the heater voltage. That will give you something to compare with as it may be this one tube has much higher current demands than expected. The other voltages look pretty good for a 6DJ8 type.

  The instructions I gave were for the pins of a socket 7 tube. The principle is the same for any tube you just have to identify what each pin is connected to. The best place to take measurements is the most convenient to your setup so the breadboard connections would probably be best.