Little Dot Tube Amps: Vacuum Tube Rolling Guide
Jan 26, 2017 at 10:40 PM Post #10,591 of 12,971

ScottieB

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So I do have Sonotone EF91's but the ones I was enjoying all this week were actually Ediswan CV138's, which I believe are an EF91 equivalent. I could be wrong. I've now got the M8161's in there, and they sound much better than I recall on my MKIII. (I'm using my HD600s for all of this by the way). The Mullards (M8161) are a bit more controlled, while the Ediswans were more 'fun' especially with rock music. They really brought out the lower end like the EF95's usually didn't, though they sacrifice some detail. So, it could be that the MKIV se is better with these tubes, or maybe my ears have simply evolved lol.
 
Can someone tell me the basic differences between the EF92/91 and EF95's? Is it true the EF92/91 require more current? I thought I read that somewhere. That's what I'm basing the assumption that the MKIV works better with them on... it certainly has more oomph that the MKIII did.
 
There's not a ton of info out there on these tube, and what there is isn't the most easily approachable, so I appreciate any info!
 
edit: according to this the CV138 is the military version of the EF91: http://www.mullardmagic.co.uk/cv138-military-variant-of-the-ef91-6am6-z77-valve-for-little-dot-amp
 
Jan 27, 2017 at 4:25 AM Post #10,592 of 12,971

LugBug1

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Can someone tell me the basic differences between the EF92/91 and EF95's? Is it true the EF92/91 require more current? I thought I read that somewhere. That's what I'm basing the assumption that the MKIV works better with them on... it certainly has more oomph that the MKIII did.
 
 

IME, EF95 are fun sounding, big warm bass with slight edge in treble. EF92 (8161) more neutral and balanced - bass is especially more controlled - treble has a more rounded sound -less edge very quiet tube. EF91 is a less refined EF92 with more bass and treble. (kind of the best of both worlds but not as good as either... If that makes sense.)
 
The EF92 require more power than the EF95 and the EF91 require more power than both. The EF92/91 require a short circuit with jumpers in place (not the woolly kind you wear on a cold day :D sorry little joke there...) And the EF95 require an open circuit with no jumper. The more power the tube requires, the hotter your machine will get. With higher end Little dots this should not be an issue. 
 
On paper I would be looking to use the more powerful tube with the highest impedance headphones. EF95 are great with Grado etc. But I prefer EF92/91 with Sennheiser.
 
This is just my experience with these tubes... :) 
 
Jan 27, 2017 at 10:25 AM Post #10,593 of 12,971

ScottieB

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Of course, one man's 'fun' is another's 'boring' but yeah I think we are mostly on the same page. The synergy with the music and the headphones (and maybe even the source?) can affect all of these things as well but to me that just makes it more fun to talk about and try different combos. Tubes are so fun!
 
It totally makes sense, then, too that the 92/91 style tubes would sound better on my MKIV than I remember on the MKIII (though admittedly it was a while ago). I was quite surprised at how much bigger the MKIV is! And it doesn't get nearly as warm. Lol also the bigger EF92/91 tubes are much easier to roll in the MKIV - those tube guards (or whatever you call them) make the EF95's kind of a bitch to remove! 
 
Can you tell me more about what is actually happening when I move the jumper for the EF92/91? Is it bypassing something? Or adding something to the signal path? 
 
Jan 27, 2017 at 1:21 PM Post #10,594 of 12,971

OctavianH

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Rockin' my pair of EF92 Mullard 8161 ordered from Langrex. Very good service and fast delivery. So I recommend them to anyone.
 
Here are sitting near my previous Voskhod EF95 6J1P-EV.
 

 
And here "on the job":
 

 
Honestly I like them, and I do not feel them dull. I think it depends on the type on music and the rest of the setup.
 
In my case, with NFB11 as a DAC and HD600 as the headphones sound really nice, very clear but somehow "mellow".
 
The music is a kind of 70-80s prog rock, so a lot of guitar, cymbals and sometime piano and complex instrumental work.
 
Works really well in this setup with this kind of music.
 
Jan 29, 2017 at 1:40 AM Post #10,595 of 12,971

TontoGoldstein

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Hello, new to the site. Today I received an MK2 and I've already ordered JAN 5654W tubes to replace the stock. Did I order replacements for the little ones in the front or the big ones in the back? Question 2: I'm using this as a PreAmp, not a headphone amp, do I need to replace the power tubes? Would that make any difference? 
 
Jan 29, 2017 at 2:58 AM Post #10,596 of 12,971

LugBug1

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  Hello, new to the site. Today I received an MK2 and I've already ordered JAN 5654W tubes to replace the stock. Did I order replacements for the little ones in the front or the big ones in the back? Question 2: I'm using this as a PreAmp, not a headphone amp, do I need to replace the power tubes? Would that make any difference? 

The Jan tubes are driver ones and are the little ones at the front. You don't need to replace power ones if you are happy with them. If you do then you can't go wrong with Russian 6n6p these are popular and fairly cheap.
 
Just make sure your power amp is not DC coupled when using the LD as a pre, as the results can be disastrous. Its mentioned in the manual. Enjoy :) 
 
Jan 29, 2017 at 11:45 AM Post #10,597 of 12,971

Share2Care

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Good Afternoon Ladies & Gents.

As tube rolling is starting to infiltrate my mind, I jad a Little Red Dot MK1. Picked up a few different tubes as I am looking forward to see the amount of differences with of course keeping burn and quality of music being played. What a terrible day having to listen to tunes all day and warm up my hands on the tubes (not touching of course lol!)

Need some advice please. Looking to purchase two matched pairs of this tube RCA 5654 (Black Plate) Good for a range but lows and bass seem to be mentioned. Are any of these tubes Russian or were Russian made at any point as I have someone who is so kind to match and send it over.

So thanks for the advice. It is appreciated :)
 
Jan 29, 2017 at 11:52 AM Post #10,598 of 12,971

Whelkie D

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Yes Mordy, I've just swapped the stock Chinese power tubes on the LD MK2 for some Soviet 6N6P ones. There is a huge difference to the bass - sounds much fuller. I wasn't expecting such a huge difference as people had said that the power tubes don't really alter sound quality. Would recommend upgrading them as well as the driver tubes.
 
Jan 30, 2017 at 6:26 AM Post #10,599 of 12,971

NotSoTastyPi

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Hey guys, any tips on power tube replacements? I am already rockin' M8100 on my mk2 + Hd600's and i love it. Thought about adding some 6N6P ECC99 because ive heard the lows and mids are the best, anyone had any experience with those?
 
Jan 30, 2017 at 7:41 PM Post #10,600 of 12,971

dobigstuff

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  Regarding the Electro Harmonix 6H30PI, they make my mkiii run pretty hot, does anybody know of any possible effects/lifespan on the mkiii?.

Scutey:
 
I use my HD 700's with a Little Dot MK III with these tubes:  
 
Electro-Harmonix 6H30Pi for the Power Tubes.
Telefunken 5654 for the Driver Tubes.  
 
Sounds Awesome.  Tight Bass.    
(I also use an MIT Magnum Power Cord and MIT Matrix 6 Interconnects)
 
Thx
 
Jan 30, 2017 at 7:46 PM Post #10,601 of 12,971

ScottieB

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Does the MKIII need a mod for the 6h30-PI tubes? Or did they maybe change it? I'm pretty sure back in the day at least (like 2008/2009) it needed a mod, and trying to run those tubes in my MKIII is what killed it (though it worked for a couple weeks). Sorry - don't want to add any confusion I'm legit curious!
 
Jan 31, 2017 at 4:06 AM Post #10,602 of 12,971

OctavianH

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Would be very nice if someone can update the main post with new info, there are a lot of tubes missing which are described here, for example Telefunken and Siemens and so on..
 
In the meantime I plan to buy some Beyers T1.2 600Ohm. Let's hope I will not regret this decision.
 
Jan 31, 2017 at 6:50 AM Post #10,603 of 12,971

dobigstuff

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  Does the MKIII need a mod for the 6h30-PI tubes? Or did they maybe change it? I'm pretty sure back in the day at least (like 2008/2009) it needed a mod, and trying to run those tubes in my MKIII is what killed it (though it worked for a couple weeks). Sorry - don't want to add any confusion I'm legit curious!

ScottieB:
 
I did not have to adjust settings nor did the Little Dot III need any Mod.  Sorry I don't know the year of manufacture.
 
Jan 31, 2017 at 12:02 PM Post #10,604 of 12,971

Share2Care

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Good Afternoon Ladies & Gents.

Need some advice please. Looking to purchase two matched pairs of this tube RCA 5654 (Black Plate) Good for a range but lows and bass seem to be mentioned. Are any of these tubes Russian or were Russian made at any point as I have someone who is so kind to match and send it over.

So thanks for the advice. It is appreciated :)


Any help please?
 
Jan 31, 2017 at 12:13 PM Post #10,605 of 12,971

MIKELAP

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Good Afternoon Ladies & Gents.

Need some advice please. Looking to purchase two matched pairs of this tube RCA 5654 (Black Plate) Good for a range but lows and bass seem to be mentioned. Are any of these tubes Russian or were Russian made at any point as I have someone who is so kind to match and send it over.

So thanks for the advice. It is appreciated
smily_headphones1.gif


Any help please?

Its a well known  fact that you do not need matched pairs in these amps 
 

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