Little Dot MKIII Tube Rolling - Page 12

Thank you sir! It did give me an idea though. If you took some really small diameter heat shrink, and covered the first 3-4mm of the pins as they come out of the glass of the tube, you could then set the tube in the socket, until the heat shrink hits the socket. This would protect your connections and give you the 3-4mm raise you wanted. Think it's worth trying?

Why are we pulling the tubes partially out of their sockets again?

Russian NOS 6Zh1P-EV EF95 Compatible Driver Tubes

I've been using these Russian NOS 6Zh1P-EV EF95 compatible driver tubes for about 150 hours now. I'll share what I know about them. All my impressions have been using the Little-Dot MKII tube amplifier:

First, they have a unique design. There are three molded indentations running down the length of the outside diameter of the tubes. This suggests they were "secured" tight in whatever original use they had. This also suggests they are extremely rugged for that same original use. I wouldn't be surprised if they were made for military aircraft use.

Second, they took less than 40 hours to mature. I'm not sure if this is due to their heavy duty construction, or close tolerances (higher quality) internally. My guess would be the higher quality.

Third, they have become my favorite EF95 tubes, for all types of music. They have no noise, excellent control over all frequencies, present an amazing amount of dynamics and a sound stage that is more than pleasing. Using the best sources I have, these tubes really show their stuff, while maintaining some of that "tube" warmth we all expect.

Forth, I would have to say these little wonders are directly competing with the better EF92 tubes. The frequency response is surprisingly flat, highs are extended and clear, and the lows are just fantastic! Plenty of clean punch, while showing the ability to reproduce those bass ranges where bass guitars and synthesizers like to play.

Fifth, the cost is so low for this kind of performance, everyone should get a set before demand raises the prices. I have no idea if these tubes are stock piled, but they are showing up more frequently on eBay. For the MKII, these little gems have become my new standard of performance for EF95 tubes. I hope everyone who has a MKII or MKIII, will acquire a set. They are just too nice to pass on.

[QUOTE=Dept_of_Alchemy;3775433]Why are pulling the tubes partially out of their sockets again?

The idea HeadCheck brought forth, was that the tube heat was directly being absorbed by the top plate. He had raised the tubes up, and thought for sure he could tell a difference in the temperature of the entire amp. So, I decided to bench check the idea, to see if heat transfer (directly) was truly adding to the housing of the amp. The temperatures suggest that while small amounts of heat (4-5 degrees) were not attributable to the overall heat of the unit, they did show up on the top plate and face plate. Not really anything to worry about, just nice to know facts.

Sorry DoA. I first raised this little experiment in the "joining the little dot family" thread, but sort of jumped track here too

Nice kitty

Man, that cat has the serious bug eyes!
It was a fun test though. It answered some questions I had in my mind as well, so it was worth it.

Now I want to know why there are so many different metals used for the pins. I understand the ruggedness side of the equation, like salt air, high altitude and anti-corrosive measures, but are there other considerations that were made on some older tubes?

Hello everyone. I got my LDM MkIII second hand with no jumpers. Are these the things I need if I decide to try tube rolling with the jumpers in?

Maplin > Jumper Pins

Thanks for any feedback

Jumpers are only needed for EF92, EF91, CV138, CV131 and similar

Stock 5654's and EF95 varieties do not need them. You can get jumpers at any computer supplies or electronics hobbyist store.

Thanks. Is the link I've given the jumpers that I need?

Yeah, but you won't need 50 of them

Cheers. They sell them with "handles" as well which might be less fiddly than using pliers/tweezers, if the handles are not too long.

Maplin > Jumper Pin with Handle

Those look cool, but if anything the handle extention may not be long enough to grab hold of below the chassis. The jumpers are tiny and the pins are recessed pretty deep. Anyway, enjoy your amp!

E

Well, I said I wasn't going to buy any more EF95 tubes...

Penchum

For those of you duking it out on the auction currently on ebay, this seller has'em in batches of 4 or 8 for less with buy-it-now:

6AK5W - 5654 - 6ZH1P-EV Tubes. Set of 8 - eBay (item 290203078573 end time Mar-01-08 12:23:14 PST)

I am correct in this r i not Penchum?

Yes sir! Those are the ones! If you look close at his pics, you'll see the indentations in the tube glass, running up and down, which makes them kinda unique.

Cool! I already bought some

I figure at the price it's a can't lose.