[sgbwill2]

Anyone care to comment on whether their 6SN7 tubes also distort at high volumes? and possible solutions? so far not very impressed with these tubes as mids + highs may have improved however there is still bass distortion even at lower volumes. Still yet to try the C3G's as I am waiting for the 7 pin miniature extenders. Hopefully I have better results with the C3G's than the 6sn7's.

 

[kvtaco17]

  Anyone care to comment on whether their 6SN7 tubes also distort at high volumes? and possible solutions? so far not very impressed with these tubes as mids + highs may have improved however there is still bass distortion even at lower volumes. Still yet to try the C3G's as I am waiting for the 7 pin miniature extenders. Hopefully I have better results with the C3G's than the 6sn7's.

I never had that issue... at all volume levels my 6SN7's were silent. This was with the LD MK1+.

 

[sgbwill2]

Thanks for the reply. I must have a problem somewhere then whether its the adapters or the extenders. Doubt its the tubes as I have tried 4 different pairs and all are distorting =/

 

[kvtaco17]

  Thanks for the reply. I must have a problem somewhere then whether its the adapters or the extenders. Doubt its the tubes as I have tried 4 different pairs and all are distorting =/

Agreed! I would check your grounds... also the DC output of your voltage regulator with an actual voltmeter... the one's with the display like to lie...

 

[sgbwill2]

Well the stock tubes don't distort at all so that leads me to believe it must be the adaptor or 9 pin extenders for the 6sn7's

 

[kvtaco17]

I ran an external dc regulator for my 6sn7's... So that may be the difference...

 

[gibosi]

Are you using an external DC heater power supply? If not, you are likely exceeding the LD's internal heater power supply capacity. Probably not safe.... 
 
And if you are using an external heater power supply, have you tied the negative out to a chassis screw on the amp?
 
Also....  are you using 6SN7's as drivers? Or as power tubes?

 

[sgbwill2]

Been running the 6sn7's now for a few more hours and the distortion has all but disappeared. Strange; seems like whatever was causing the problem has sorted itself out. Still some when playing the amp on full though its only minor and i doubt i'll ever be listening to it at those levels. more than happy now

 

[sgbwill2]

I am not using a external DC heater power supply. amp is cooler than with the stock tubes for some reason. which is good. im using the 6sn7's as power tubes

 

[tjw321]

  Been running the 6sn7's now for a few more hours and the distortion has all but disappeared. Strange; seems like whatever was causing the problem has sorted itself out. Still some when playing the amp on full though its only minor and i doubt i'll ever be listening to it at those levels. more than happy now

Sounds very similar to a problem I had with another amp. Reseating the tube nearly fixed it for me. Cleaning the contacts and reseating the tube completely fixed it. Maybe one of your connections is a little dodgy?
 
Incidentally my Little Dot Mk III arrived a few days ago. I haven't done any rolling yet, but I have a pair of Voskhod 6ZH1P-EVs and a pair of Mullard M8100s on the way. Thanks to everyone for all the info in this thread.

 

[gibosi]

  I am not using a external DC heater power supply. amp is cooler than with the stock tubes for some reason. which is good. im using the 6sn7's as power tubes

 
Used as power tubes, you do not need an external DC heater power supply. The 6SN7 heaters draw only .6 amps whereas the stock power tubes draw around .85 amps, so they do run cooler. However, if you ever decide to run 6SN7's as drivers, you will need an external heater.
 
And I never give up on a noisy tube until it has burned in for at least 20 hours. Nearly always, they quiet down.

 

[Rossliew]

No such distortion but i listen at fairly low levels around 9 o clock. I do note that the 6sn7/6hm5 combo does produce some distortion with some of my bass heavy music. Could be the tune's mastering but i doubt it as it sounded fine with other tube configs. Btw, am using the Mk3 with HD800.

 

[hypnos1]

 
 
Well folks, the Chatham 6AS7Gs have been in situ now for some time and they definitely give more than the RCAs...methinks I have pushed my poor IV SE to its limits...don't think I can ask any more from her (luckily still no signs of objection - what a machine lol!). Certainly shall not be needing to look at the Darkvoice ( NOR the Glenn!) for a VERY long time...sigh from wallet..

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So it looks like it's finally bon voyage, and my (patient) other half; garden; Koi and camera can get a bit more attention at last...but boy, am I gonna miss this exciting journey, not to mention some great guys - past and present. I never thought getting into valves (vacuum tubes!) would be such fun or so fascinating...main amp next, perhaps?...sorry missus!!
 
I would like to thank - once again - all who have helped me along the way this past year, and I wish you all HAPPY CONTINUED ROLLING!!
 
Shall certainly be keeping an eye on what's cookin' though...

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Cheers everyone.

 

[mordy]

Hi hypnos 1,
 
Glad to see that you have found the ultimate level in modding the LD amp! I am working on using 6080/6AS7 tubes as power tubes as well. Can't see any wires from the extender sockets, but I assume that they are there, going to a voltage regulator and an external power supply. You probably wrote about it before, but could you describe what you are using to power the Chathams?
 
My idea is to use two independent 5A voltage regulators. Would one 20V 2.5A PS suffice for a pair of 6080 tubes? I think that at 6.3V this PS translates into 8A. (The tubes draw 2.5A)

 

[hypnos1]

  Hi hypnos 1,
 
Glad to see that you have found the ultimate level in modding the LD amp! I am working on using 6080/6AS7 tubes as power tubes as well. Can't see any wires from the extender sockets, but I assume that they are there, going to a voltage regulator and an external power supply. You probably wrote about it before, but could you describe what you are using to power the Chathams?
 
My idea is to use two independent 5A voltage regulators. Would one 20V 2.5A PS suffice for a pair of 6080 tubes? I think that at 6.3V this PS translates into 8A. (The tubes draw 2.5A)

 
Hi mordy.
 
I look forward to hearing your findings when you complete your mod, and do hope you get the same thrilling results as myself, lol!
 
Ah, I'm glad I've managed to minimise the 'intrusive' look re the mod - another advantage of making my own adapters!...the wires exit the back and almost disappear. Helped, of course, by the fact that (luckily!) the MKIV doesn't need the extenders.
 
I was using my old laptop power supply/charger at first, but as I wanted it back(!) I opted for a cheap 12V 6A power supply off Amazon - looks like the laptop kind, but meant for those strings of led lights ( £10, on UK site). I'm afraid I'm no expert on electricity, so cannot say for sure if your assumption is correct re higher amps at lower voltage within the same unit being OK...sounds OK, but hopefully others with greater knowledge can confirm?...
 
I wish you the very best of luck, mordy...and that you have more fruitful results with the MKIII than ilm2 had 

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