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Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 336

post #5026 of 10566
Quote:
Originally Posted by gibosi View Post

 

If... I get a pair of these, I would like to remove the top metal cap, but is it possible to easily do so without disturbing the metal base?

 

It isn't. See http://www.head-fi.org/t/600110/2359glenn-studio/2475#post_9329427

post #5027 of 10566
Quote:
Originally Posted by gibosi View Post

 

The published curves for the C3g strapped as a triode were generated using one or the other of these strappings, so one would think that somewhere there is some fine print indicating precisely how this was done.

 

It's right there in plain sight: "g2 an a, g3 an k". In German, obviously.

 

post #5028 of 10566
Quote:
Originally Posted by Oskari View Post
 

It isn't. See http://www.head-fi.org/t/600110/2359glenn-studio/2475#post_9329427

 

Too much work for me! So if I get a pair of these, the metal caps will stay on. lol

 

Quote:
Originally Posted by Oskari View Post
 

It's right there in plain sight: "g2 an a, g3 an k". In German, obviously.

 

 

I see it now! Thanks! 
 
So the strapping that Hypnos1 is using is the one we want to use.

Edited by gibosi - 2/14/14 at 7:16am
post #5029 of 10566
Quote:
Originally Posted by Oskari View Post
 

 

It isn't. See http://www.head-fi.org/t/600110/2359glenn-studio/2475#post_9329427

 

Oskari - thanks for the post. Nice to see more coverage of the C3g...please also see below...

 

Quote:
Originally Posted by gibosi View Post
 

 

Too much work for me! So if I get a pair of these, the metal caps will stay on

 

gibosi - can understand your reticence, but IF you do try these beauties (and anyone else for that matter), can I just point out that the method shown (ie using a flat-blade implement) is asking for trouble, and cannot understand its recommendation. FAR better (and easier) is to use a SMALL pair of pliers and prise away the outer cover from the metal base, as it (the crimped cover bottom) is of very soft metal and comes away nice and neatly with minimal effort. And with a bit of 'jiggling' the tube plus metal base pops out unharmed.

The tubes unsheathed look SO much better than black canisters!

 

I shall be taking a good few pics of my next adapter construction this weekend, so will post them ASAP...

post #5030 of 10566

Thank you for the reply Gibosi

 

I was mistaken and thought the 6sn7 tubes didn't need external power. Looks like it was the 6SL7GT I need. Are there any 6SL7GT tubes that would outclass the Yugo 6hm5 tubes?

 

I'm going to have to give the whole idea a re-think as I really wanted to keep the price down as much as possible. I'll have a little dig around and see if I already have a power supply I could use.

 

Thanks again!


Edited by samtheman - 2/14/14 at 10:46am
post #5031 of 10566
Quote:
Originally Posted by gibosi View Post
 

 

Too much work for me! So if I get a pair of these, the metal caps will stay on. lol

 

 

 

Re the strapping, I must admit I just cannot see how any other configuration could bring anything else to the table - everything is so wonderfully integrated. So it may be some good time before I play around with the status quo! Will therefore be linking C3gS pins 2 & 7 inside the adapter tomorrow, for neatness sake...


Edited by hypnos1 - 2/14/14 at 11:32am
post #5032 of 10566

Hi samtheman,

 

I think that you will be happier with the 6SN7 tube than the 6SL7 tube. A voltage regulator is less than $5 and perhaps you have an old lap top PS sitting around - don't see any reason why you cant use one of those. The lap top PS is usually rated around 19V.

 

Good luck!

post #5033 of 10566

Thanks for the advice :) I suspect you are right re the 6sn7 tube. I have a spare AC adapter rated as 5v 2000mA output - would that do the job?

I'm also wondering if I could get away without the external power supply for a few hours to get a sense of the sound and then decide if it's worth getting the power supply and regulator?


Edited by samtheman - 2/14/14 at 1:56pm
post #5034 of 10566

I heard you were talking about using 6SN7 as powertube. This was my totally hum and noise free adapter for octals, made some months ago.

With 6SN7 you lose some maximum power to headphones, but otherwise they work like charm. Btw Ten 6SL7GT tube is not bad at all. Been burning it in for some time with my diy amps.

post #5035 of 10566
Quote:
Originally Posted by samtheman View Post

Thanks for the advice smily_headphones1.gif I suspect you are right re the 6sn7 tube. I have a spare AC adapter rated as 5v 2000mA output - would that do the job?
I'm also wondering if I could get away without the external power supply for a few hours to get a sense of the sound and then decide if it's worth getting the power supply and regulator?
5V will not do it..

As to the other question...
99flaming-snake-eyes-dice.jpg
Edited by TrollDragon - 2/14/14 at 3:05pm
post #5036 of 10566
Quote:
Originally Posted by samtheman View Post
 

Thanks for the advice :) I suspect you are right re the 6sn7 tube. I have a spare AC adapter rated as 5v 2000mA output - would that do the job?

I'm also wondering if I could get away without the external power supply for a few hours to get a sense of the sound and then decide if it's worth getting the power supply and regulator?

 

You need an AC adapter that puts out at least 10V at 400ma. I don't know that I have ever seen a 10V adapter, but 12V adapters are common.

 

Rolling 6SN7s in your LD without an external PS is like rolling dice....  Your amp might be fine for a short time. Or it might not. I am sorry, but I am not willing to encourage you.

 

And further, it may be that the Tung Sol you are looking at does not meet your fancy. But perhaps a Sylvania, RCA., Raytheon, Hitachi, or what have you, might be wonderful. I think you cannot judge an entire tube family from a sample size of one.

 

To be very frank, if you cannot afford to try 6SN7s without cutting corners and taking risks, then I think you are much better off staying with your 6HM5s until you can afford to do it right.

 

Cheers

post #5037 of 10566

Thank you all for the suggestions and very sensible warnings. I will heed them and if I decide to build the adapter I will do it properly with an external power supply.

 

Thanks again 

post #5038 of 10566

After some more digging around, I found an old hard drive power supply with these output ratings: 12Vdc -- 1.5A

 

Am I right in assuming this will do the job? I've already ordered the other parts so am committed to making this work - and to doing it safety  :)

 

Thanks

post #5039 of 10566
Quote:
Originally Posted by samtheman View Post
 

After some more digging around, I found an old hard drive power supply with these output ratings: 12Vdc -- 1.5A

 

Am I right in assuming this will do the job? I've already ordered the other parts so am committed to making this work - and to doing it safety  :)

 

Yes, that adapter is more than adequate. Have fun! :)

post #5040 of 10566

Guys, do you know if Voshkod 6ZH1P-EV = 6J1P-EV? I'm looking for the real 6ZH1P-EV for a Little Dot MkIII.

 

I found this matched pair on ebay at a very good price:

http://www.ebay.com/itm/6ZH1P-EV-6J1P-EV-EF95-5AK5-Matched-pair-Mil-Tubes-TOP-/141184491953?pt=DE_TV_Video_Audio_Elektronenr%C3%B6hren_Valves&hash=item20df4061b1

 

But the seller says "6ZH1P-EV / 6J1P-EV" and I read several post in these forums where people doubt if 6ZH1P-EV = 6J1P-EV, so I'm confused.

 

There is another, pricier auction wich says 6ZH1P-EV only:

http://www.ebay.com/itm/301050973465?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

 

I appreciate any information,

Raul

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