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Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 200

post #2986 of 8739
Quote:
Originally Posted by mab1376 View Post
 

 

I bought those adapters and they didn't work

 

They work fine here i put my amp on EF 92 setting and my EF95 tubes in the sockets if i remember when he first made them they were not working but he sent me another pair with the right configuration that work fine i have been using them for a while now same for the 6AH6 and 6AU6 socket adaptor 


Edited by MIKELAP - 9/19/13 at 6:48am
post #2987 of 8739
Quote:
Originally Posted by MIKELAP View Post
 

 

Your not alone to like these tubes they are among my favorite tubes also. I have 10 sylvania JAN 6AU6WA on the way will be good for a while with these .Burnin in G.E. JAN 6136 at the moment you probably know that you can buy socket adaptors for those 6AH6and 6AU6 TUBES right. heres a picture and a link where you can buy these adaptors in China they are $38.00 shipped if your interested the way they are made your amp is on the EF95 setting you put the adaptors in the amp and your 6AH6 OR 6AU6 tubes in adaptors and your good to go .                                                 http://www.ebay.com/itm/2x-6AU6-6AK5-tube-adapter-socket-converter-free-shipping-/300960155101?pt=Vintage_Electronics_R2&hash=item46129f85dd                                                                                                                                                                                                                                                                                 

Processed By eBay with ImageMagick, R1.1.1.M2b 

 

These infact do look very useful for sure!

If I do gather a collection of 6AW6's which I am thinking would be a good idea, I'll get a pair of these to go along with. A lot easier than soldering to the pins of the tube.
 
These would be so easy to DIY but there are very few B7G parts that I can find, lots of sockets but the plug bit is the hard one to locate...

:beerchug: 

post #2988 of 8739
Quote:
Originally Posted by TrollDragon View Post
 

 

These infact do look very useful for sure!

If I do gather a collection of 6AW6's which I am thinking would be a good idea, I'll get a pair of these to go along with. A lot easier than soldering to the pins of the tube.
 
These would be so easy to DIY but there are very few B7G parts that I can find, lots of sockets but the plug bit is the hard one to locate...

:beerchug: 

 

When needed i use both pair of socket adaptors leaving EF92 setting on amp this is my famous REACH FOR THE SKY setup :basshead:

                                                                                                                                                         

 

 

 

post #2989 of 8739
Quote:
Originally Posted by MIKELAP View Post
 

 

When needed i use both pair of socket adaptors leaving EF92 setting on amp this is my famous REACH FOR THE SKY setup :basshead:

                                                                                                                                                         

 

I just Love it! :D

 

The cloud and sky are nice touch. It looks like some sort of Candu reactor type thing, or the smoke stacks from the Coal Fired power station down here in Dartmouth.

post #2990 of 8739
Quote:
Originally Posted by MIKELAP View Post
 

 

They work fine here i put my amp on EF 92 setting and my EF95 tubes in the sockets if i remember when he first made them they were not working but he sent me another pair with the right configuration that work fine i have been using them for a while now same for the 6AH6 and 6AU6 socket adaptor 

 

I used them in reverse lol, EF95 settings with the adapter and 6AV6 tubes.

post #2991 of 8739
Quote:
Originally Posted by mab1376 View Post
 

 

I used them in reverse lol, EF95 settings with the adapter and 6AV6 tubes.

When i got the second pair they were not working either because i told the guy i wanted the adaptors to plug in the amp at the EF95 setting but he made them to use the EF92 SETTING i found that out when i went to the guys website for the adaptors and went to the bottom of the page and he specifies what setting to use in the amp.

post #2992 of 8739

"And now for something completely different."

 

OK, so I tried to ramp up the difficulty level a bit lol. Don't try to reproduce the experiment I'm about to show you at home, unless you really know what you're doing -I hardly am!

 

So, I'd been looking for 7-pin socket adapters -versatile adapters, not one-shot adapters that make a tube type into an other and nothing else- for a while, and finally bumped into a website that sold quality NOS adapters for cheap. Shipping across the world was cheap too, so I bought three pairs of adapters. They finally got here today.

 

Now, I'd had -and still have- a number of ideas in my head of new tube types to try on our LD amps, most of which would require some thorough pin reworking, but there was this one experiment I wanted to try first; ironically it was the most challenging one. Using one of those ubiquitous double triodes that everybody loves on my LD amp! It's a good thing I had an old mil spec Mullard M8162 lying around (it came with a box of very random tubes months ago, back in the EF91 days). So, I started working on adapting that single 12AT7 tube on my two-separate-pentode LD!

 

Here's a picture of the adapter/tester/savers I got. Brand name is Vector, and they seem to have been a reference back in the tube days.

 

 

The tube I adapted: Mullard M8162 / CV4024, mil spec 12AT7, Mitcham-made; barely legible when I took the picture 8 months ago, and even less now that I manhandled it into submission...

 

Just your basic 12V, center-tappable, high-mu double triode. I just realized that this a $30 tube on ebay, actually, so maybe not that basic.

 

 

 

I'll cut to the chase and just illustrate what I did with a picture (how's my "reach out to the gods" setup Mikelap lol?), just so you can see just how unpractical this whole setup is -and how crazy an attempt to adapt a tube it is!

 

Basically, I chopped up some old computer cables and stripped them on one end. The other end I used with its metal hole to squeeze onto the tube pins as DIY air socket holes (R) (with great difficulty and little fate that the contacts will last long). The stripped end of the wires I attached to the socket adapters' tester tabs in a non-destructive way (the adapters can be unscrewed and opened -which I had been hoping for since it was what I needed- so I squeezed the bare wiring underneath the tester tabs and screwed the adapters closed again).

 

Made each of the nine wires (9 pin double triode) go to the appropriate pins on the tube, and socket holes on the amp; using the heater center tap to power the tube (so pins 4+5 to one of the heater pins on one of the sockets, and pin 9 to the other heater pin on the same socket), and rerouting each triode pins to the appropriate pins on each socket. The pieces of paper below the tube aren't to make it pretty; they're there because I was very scared that the wires would touch each other, and they would have otherwise!

 

Interestingly, it only took me two attempts to make this mod work (I was expecting it to fail; I didn't even know if the tube was good). First time I had messed up some wires on the right side, so the heaters -fortunately- didn't power on, and I was spared the awful PPSHhhh noise, just got silence.

 

 

On my second attempt -a bit more thorough than the hasty first one- everything worked perfectly!! Filaments lighting up, music in both channels: success! I did get a bit of noise in one channel for half a second, but I know that's because the tube is barely attached to the wires and kind of hanging from nowhere, so I wasn't surprised. It worked flawlessly for 15 minutes after that.

 

What is even better is that it sounded great, which is not an easy feat considering that everything was wrong with this mod: wrong number of tubes, wrong tube type, wrong number of grids, extra 50 years old adapters, 15cm of crappy wiring without shielding, dubious tube...  But still, it sounded as good as my current fav' 6DT6 tubes, so top-tier. Very natural and musical sound, detailed and realistic but still toe-tapping; I guess double triodes are cool too huh?

 

It does kind of look like the amp is holding up a tube as an offering to the gods though lol. I'd imagined it would have looked even more rigged, so this isn't even that bad for a quick test.

 

 

Like I said earlier, the adapters unscrew, and the whole top part comes off with the pins and tester tabs, so you can squeeze stuff in there and not destroy an adapter by soldering wires for every new pinout you want to try.

 

 

Anyway, interesting experiment. Unpractical for sure, but my goal was just to prove that it worked, not to leave it there. Not only did it work but it sounded great! So, I'll be investigating this a bit longer. If a 12V center tapped double triode can be made to work on this amp, you can sure bet a 6V double triode like the 6DJ8 would too! And these are supposed to be very very nice tubes.

 

Notice how such a setup would use less power than our typical tubes: a single 0.3A heater instead of often two in our pentodes. Then again, the "prettier" solution using double triodes here would probably be to just use one per channel with a clean 9 to 7 pin adapter, and only use one triode out of the two in each tube. More expensive and a bit silly, but it would be the only way to not have a tube floating in the sky on top of your amp between sockets...

 

I had to open up my amp a few days ago and took the opportunity to take -non-destructive- pictures as best I could. You can't see much but it gives you a pretty good idea of what is in a MK IV SE, seen from the front. Pics can be enlarged if you actually want to see something.

 

 

Edit: See that wooden thing on the picture above? That's my solution for changing jumpers easily. Glued a match stick to an elongated jumper so that the wooden part pokes out by maybe 2 mm outside the amp, meaning that I can grab and change the jumpers by hand.

 


Edited by Audiofanboy - 9/19/13 at 9:06am
post #2993 of 8739

Hi guys.

 

The RCA 6DT6As have finally arrived, and with 20+hrs on 'em I have to admit my beloved 'Siemens' EH90s (Blackburns) are being put slightly to shame...these are giving more in all departments (which I didn't think was really possible - should have known better!), especially -  as AFB has mentioned - in the mid-bass area. They are SERIOUSLY good tubes...well done the Masters who have found and championed these tubes. Particularly as they do not need any fancy mod - just 6-7 strap on my MK IVSE, and certainly nothing like Audiofanboy's amazing/scary last experiment. CRAZY man!!

 

I think I may have also been a little lucky in getting 2 of the 4 I received appearing absolutely identical - with smooth plates - while the other 2 have ribbed plates, and NOT looking so identical (shades of  'Siemens' tubes all over again...). These things are pairing with my 6N30P-DRs like a marriage in heaven - and that's with my humble HD650s (helped along by pure silver cable, though).

 

Can't wait to see what another 20 hrs burn-in brings - surely they can't get any better than this! Or can they?,,,

 

BTW - they are WAY louder than even the EH90s on 6-7...

post #2994 of 8739

Mike, re the super tubes:

From the pics they look not too bad however what some sellers will often do is use “stock real tube photos” instead of photos of the real tubes. Tricky yes! So I have asked for close up pics of the flaps both sides, bottom of the mica, getter, and  the tubes on piece of paper with my name and date in the pics. The response is usually an ok give me some time or a defensive no. if they pass the test on page 96 then i say go for it and definitely go with the ones from 1979

Hope this helps

Gary


Edited by mojorisin35 - 9/19/13 at 9:29am
post #2995 of 8739

A pair of Tung-Sol 6AV6 arrived today:

 

 

These have the "box" mounted on the top mica, GE-style diode plates with halo getters, and look very similar to the Multivox/Toshiba 6AV6. However, the Tung-Sols have black plates, and the mica and getter splash are different. Moreover, 6AV6 USA is etched in the glass, so it would appear that these were not manufactured in Japan by Toshiba. Next, will cut off some pins and begin to burn them in.

 

 

And the Toshiba 6AV6:

 

http://vintageaudiotube.blogspot.com/2011/10/toshiba-6av6.html

post #2996 of 8739

I guess AFB is the Dr. Mengele of LD amps.

 

 

...just kidding lol, looking forward to how the 12AT7 works out for you!

post #2997 of 8739
Quote:
Originally Posted by mab1376 View Post

I guess AFB is the Dr. Mengele of LD amps.




...just kidding lol, looking forward to how the 12AT7 works out for you!

I would do anything for science lol!

The next iteration will look less cruel; I ordered some 9 pin sockets to solder.

Don't worry though, I have a few other better looking ideas in the pipeline.

That picture does look half way between a tube getting sacrificed and just a technical aberration...
post #2998 of 8739

Someone can please explain to me  what is the meaning of O-getters or D-getters ?

 

What part of tube i must to look ? For example, i'm referring to my TS 6AH6WA, but i have no idea where and what to look.

 

Thank's


Edited by Iron58p - 9/19/13 at 12:28pm
post #2999 of 8739
Quote:
Originally Posted by Iron58p View Post
 

Someone can please explain to me  what is the meaning of O-getters or D-getters ?

 

See http://www.head-fi.org/t/563884/little-dot-tube-amps-vacuum-tube-rolling-guide/555#post_8951850

post #3000 of 8739

Ok, thank's again, now i know that my TS 6AH6WA 1964 are O-getters.

 

I think to be lucky :regular_smile :

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