Little Dot Tube Amps: Vacuum Tube Rolling Guide
Mar 5, 2015 at 9:03 PM Post #9,257 of 12,832

gibosi

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  Hmmmm... That sounds very similar to something I said a long while ago...

 
Yes, I remember... :)
 
However, the fact remains that even an average double triode sounds better than any 6AK5 in our LDs. Using crude pin-adapters and external power supplies, we have taken our LDs to heights beyond our wildest dreams.
 
And in my case, I have been adapting and trialing all these tubes with the understanding that they were an investment. I wasn't sure exactly what amp I would get, but I knew that eventually I would purchase an amp that would do these wonderful tubes justice. And it finally happened.
 
So it seems to me that one can adapt their LDs to use double triodes, C3gs and even 6AS7s. And the end result is indeed very good. And it just might be good enough. But if not, there are other amps than can reveal the true potential of these tubes.
 
Speaking of tubes, I have a couple of ECC808s coming, one a Valvo manufactured in Hamburg, and the other a Telefunken. These are closer to a 12AX7 than a 6SN7, so I will be trialing these in the my LD.  The LD 1+ lives on...  :)
 
Mar 6, 2015 at 8:31 AM Post #9,258 of 12,832

SonicTrance

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  As some might remember, I have been thinking for over a year about moving beyond my LD 1+ to a 6AS7G-based OTL. Of particular importance to me was being able to use all my favorite tubes in my new amp. Today, I took delivery of a Glenn OTL. Of particular note, this amp can use either a pair of G3gs or any SN7 (6SN7, 12SN7 or 25SN7). I am not aware of any other 6AS7-based OTL that is designed from the ground up to use a pair of C3gs as drivers as well as SN7s.
 
Pictured, with a 3DG4 rectifier, Ken-Rad 1633 (25SN7) and two Chatham 6AS7s. And yes, it sounds much better than my LD 1+!
 

 
In fairness, we need to remember that our LDs were designed to use triode-strapped 6AK5s, not 6SN7s or any other double-triode, and certainly not a pair of C3gs. For sure, these tubes sound great in our LDs, much better than any 6AK5, but since the biasing is not optimal for these tubes, they cannot sound as good as they do in an amp that has been carefully and deliberately designed to use these tubes.
 
And now please excuse me as I return to the music. :)

Congrats on the new amp! Looks great and I bet it sounds great as well
L3000.gif
 
 
  Hi Mister X,
 
If you have a voltmeter you could just touch the pins 4&5 and measure the voltage at the tube. Should be possible if the pins on the adapter are long enough. Just be careful to touch the right pins.
 
(Jag vaxte up i Sverige och talar fortfarande svenska efter 47 ar i Amerika.)

That would be a real hassle cause I've cut of pin 4 and 5 on the adapters and soldered the psu cables to the cut of pins.
Here's what it looks like:
 

 

 
I've only had the chance to listen to these 6H5C's for a couple of hours but I do notice a big difference compared to the the 6SN7's. Bass is punchier and deeper and no background noise. No need for any impedance adapter with low Z cans with these power tubes. This makes me want to upgrade to an MK9, lol. But then I couldn't use the lovely C3Gs...   
 
Mar 6, 2015 at 10:25 AM Post #9,259 of 12,832

mordy

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Hi Mister X,
 
Your setup looks really nice - enjoy!  I use the C3gS as drivers, and a pair of 1960's Sylvania 6080 tubes as power tubes with great sound. Although I tried several other power tubes, including RCA 6AS7, Chatham 6AS7, and GE, RCA, Phillips and Sylvania Gold 6080s, I prefer the 1960 Sylvanias. Have yet to find somebody who corroborates my preference.....
 
Mar 6, 2015 at 10:32 AM Post #9,260 of 12,832

Peter_S

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Hi guys. I'm seeking some advice. My amplifier is making crackling and static sounds. I read the manual, and will clean all the contacts for the tubes. Other any other steps I should do to identify and address the source of this problem, I have different output tubes but I don't have a different power tube. I may have to get one to try to identify the issue.

I am using it as a preamp for a Trends audio 10.2 amplifier. I will also check to see if the crackling sound occurs with headphones.
 
Mar 6, 2015 at 10:46 AM Post #9,261 of 12,832

buldogge

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Which amplifier?

Is the sound from a single channel, or both?

Does the noise move channels when you swap tubes?
 
I just went thru this with my MK III...ended up having to switch out the volume pot.
 
BTW...The output, both HP jack and pre-outs goes thru the pot...FWIW.
 
-Mark in St. Louis
 
Quote:
Hi guys. I'm seeking some advice. My amplifier is making crackling and static sounds. I read the manual, and will clean all the contacts for the tubes. Other any other steps I should do to identify and address the source of this problem, I have different output tubes but I don't have a different power tube. I may have to get one to try to identify the issue.

I am using it as a preamp for a Trends audio 10.2 amplifier. I will also check to see if the crackling sound occurs with headphones.

 
Mar 6, 2015 at 1:04 PM Post #9,262 of 12,832

SonicTrance

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  Hi Mister X,
 
Your setup looks really nice - enjoy!  I use the C3gS as drivers, and a pair of 1960's Sylvania 6080 tubes as power tubes with great sound. Although I tried several other power tubes, including RCA 6AS7, Chatham 6AS7, and GE, RCA, Phillips and Sylvania Gold 6080s, I prefer the 1960 Sylvanias. Have yet to find somebody who corroborates my preference.....

Hi Mordy,
 
I'm enjoying it alright
L3000.gif
 I have a pair of those chinese Shuguang 6N13P-T on the way for me to try next. I've looked at 6080's but they're mostly available from the states and that means extra custom/import charges. None of that from China.
 
Mar 6, 2015 at 4:32 PM Post #9,263 of 12,832

Jolfr

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So I received my ei 6hm5's today, and I wanted to check before I power anything on. Do I need to switch the jumpers from where they were for the stock tubes?
So if I'm looking at the jumpers from the bottom of the amp with the headphone jack pointed towards me, should the jumpers be to the right or to the left?
Thanks once again!
 
Mar 6, 2015 at 4:40 PM Post #9,264 of 12,832

SonicTrance

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  So I received my ei 6hm5's today, and I wanted to check before I power anything on. Do I need to switch the jumpers from where they were for the stock tubes?
So if I'm looking at the jumpers from the bottom of the amp with the headphone jack pointed towards me, should the jumpers be to the right or to the left?
Thanks once again!

The jumper needs to cover pin 1 & 2 for EF95 type tubes. Don't have the mk3 myself but i guess the pins are numbered? 
 
Mar 6, 2015 at 4:41 PM Post #9,265 of 12,832

buldogge

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  So I received my ei 6hm5's today, and I wanted to check before I power anything on. Do I need to switch the jumpers from where they were for the stock tubes?
So if I'm looking at the jumpers from the bottom of the amp with the headphone jack pointed towards me, should the jumpers be to the right or to the left?
Thanks once again!


EF95 setting...
 
MK III?  Jumpers on the left when looking at the board/bottom.
 
MK II?  No jumpers/jumpers removed.
 
-Mark in St. Louis
 
Mar 6, 2015 at 7:00 PM Post #9,267 of 12,832

MIKELAP

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  So I received my ei 6hm5's today, and I wanted to check before I power anything on. Do I need to switch the jumpers from where they were for the stock tubes?
So if I'm looking at the jumpers from the bottom of the amp with the headphone jack pointed towards me, should the jumpers be to the right or to the left?
Thanks once again!

Looking under the MK3 amp arrow pointing to front                                                                                                                                                                                                                                                                                                                  
 
Mar 6, 2015 at 10:50 PM Post #9,269 of 12,832

Rayzilla

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You could read through the thread and look at the table page 585. However, in short the answer is: Ignore ebay infos and for direct replacement, get a pair of 6N6P-IR as power tubes and Yugoslavian Ei tall bottle 6HM5 driver tubes. After that, there are more options via adapters. You could also buy a pair of adapters as indicated in the table and get yourself a pair of 6SN7 as power tubes. Those would probably surpass the 6n6P-IRs.


Thanks for this information. I will try to Take a look at it in more detail when I get the chance and after I confirm on the issue raised by TrollDragon.
What tubes are in the old LD II now? If it is one of the first ones, then most of the tubes we use will not work at all. You might have trouble finding replacements for the ones you have.

I bought it used so I do not know how old or whether it is one of the first ones or not. Is there any particular way to confirm? This sounds discouraging. :frowning2:
 
Mar 6, 2015 at 11:32 PM Post #9,270 of 12,832

TrollDragon

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I bought it used so I do not know how old or whether it is one of the first ones or not. Is there any particular way to confirm? This sounds discouraging.
frown.gif

What are the numbers on the tubes you have in the amp now?
We can tell you what should work and what wont if we know what those are.
 

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