Thank you, I wanted to learn about how it works. I have output adapters that work with 12A?7 that I have used for the excellent E80CC and sweet 12BH7's. I have about 80 used "junk box" 12A?7 that I am in no rush to sort through for cosmetic pairs due to more intriguing output tube listening...

I'd like to learn more about converting 12 volt to 6 volt tubes such as the 12AU7 and 12A_7 tubes whose pins 9 are hct, heater center 6 volt conversion taps. The 12AU7 etc have the same pinout as a stock Little Dot MK III 6N6P output ("power") tubes except pin 9 in the 6N6P is an internal...

I have been experimenting successfully with dissimilar double triodes as output ("power") tubes in my Little Dot MKIII. Many of them sound very good. I have tried 6 types and believe that many other types should work well also. Many of these tubes were designed for American televisions. An...

While listening to RCA Made in Great Britain 6HM5, I looked up this list of single triodes (and a few nuvistors) and queried them on all posts on this forum. This post was the first time approximately 85% of them were mentioned. In the past people tried and posted impressions of some triodes...

April 2024: currently alternating 6SN7 and co-listed 6EM7/6EA7/6GL7 as output tubes in a Little Dot MKIII with Siemens C3G drivers. My 6SN7 are old stock and are the mid to lower-priced ones. After listening to a handful of them I have a Westinghouse 6SN7 favorite that all around sounds good...

(When installing or removing jumpers, the amp should have been off and cooled down which makes it possible the electricity harboring capacitors have discharged. IF you shut off the amp with music playing, it will continue playing music while the capacitors are discharging.) It seems you are...

Put em in the freezer for a few minutes, grab em by the pins with hemostats, and shine an led flaslight on the condensation from a side angle while rotating the tube. Sometimes the tube id quickly appears and disappears. Also try freezing longer 6 mintues or so 10 minutes or so and even longer...

Because of their ic internal connection pins? I glanced at an EL41 datasheet on frank.pocnet.net and it had data for triode connections and triodes in push-pull. I have 6AM5 tubes that a datasheet specified had an ic pin 6: do not connect anything to it. When I looked closely at the tube I...

While it may take quite awhile, because this is a hobby, I'm planning to do some reading from the library, hopefully in a book that has some practice problems, hoping to cultivate better understanding of electricity in general and tubes. Then I plan to get back in touch with a friend of my...

In case you don't know, there is a Little Dot MKVI forum on headfi.

I'm curious to know why they wouldn't work without an output transformer and how one figures that out. Is it a comment specifically about those two tubes specifically or about many tubes in general? Or is it a comment based on the idea they would need a better output transformer than stock in...

I've been rotating various brands of dissimilar double triode co-listed 6EA7/6EM7/6GL7 vs 6SN7's in my MKIII. The various brands I have auditioned of the dissimilar triodes seem to sound about the same while the 6SN7 have had more variation. The 6EA7 etc, in my opinion, YMMV, tend to beat the...

Not glowing, blown heater. If not that, replace some and see if it works again. If neither works, shucks it will cost more: call the house call tube repairman or take the equipment to his office. I color-coded connections for a 1970's solid state receiver for my parents. I also labelled the...

I've sometimes wondered if some tubes were painted colors to make replacement easy for people who did not know what all the numbers and codes on tubes mean. I've encountered sellers on facebook marketplace, Craigslist, eBay that do not know how to provide the identity of the tubes they are selling.

Months ago I negotiated the purchase of a variety pack of cosmetic pairs of $2-$3 per tube 6J2P, and -ev from Ukraine. Some had painted tips, some had various numbers of painted-on red or white dots, some were tall bottle, some short, some Svetlana and some Vinniza. The paint barely adheres to...

For the MKIII, which might be similar, I unplug the tubes, turn it upside down and can see them through holes in the housing with a flashlight.

It's a US television tube that's inexpensive in the US but perhaps not so abundant in Europe. If one looks around online, one can probably buy cosmetic pairs of 6EA7 or 6EM7 or 6GL7 for 10 to 17 pounds here including shipping. I don't know about vendors willingness here to ship to you. After...

All of the following tubes are plug and play in 6SN7 adapters. The 6EM7 draws .925Ah. The 6EA7 and 6GL7 seem to have been substitutes for televisions but draw 1.05Amps. My MKIII transformer is rated for 1.25Amps (v2 and later; the first version is probably lower). I regard 1.05 amps as...

Works well with the diodes floating/unconnected even though they are heated?

Yes was a joke. Interesting that 10 minutes or so in the freezer tended to usually work better than longer time and repeating it sometimes helped also. Perhaps one needs just the right amount of condensation. The codes tend to appear briefly while the tubes warm up and the condensation is...

I don't believe in cryo. It was a joke, risky business for postings.

Yes

Formerly a skeptic, I now firmly believe in Cryo treated tubes. I recently got a free junk box of tubes, and some are missing their alphanumeric identity. I put some in the freezer for awhile. When I take them out, I shine a flashlight on the condensation and can sometimes see their identity...

As an experiment about 45 minutes ago I powered up my MKIII with 6EM7 output (power) tubes on 6SN7 adapters. 6EM7 have two dissimilar triodes under the same glass, one low mu and the other higher, and it draws .925 Ah. It didn't explode, hasn't overheated and sounds good and has ample power...