Little Dot MKIII Tube Rolling - Page 146

IMO, if you are going to spend $200 for power tubes you might as well buy a better amp like a Woo.

Got some Amperex Bugle Boy EF91's today.  I got them for a low price and I have to say I'm really impressed.  My other favorite tubes so far are Amperex EF92's.  I'm not sure yet which I like better.  I think both of these tube sets are made by Mullard for Amperex.

Tried a pair of Mullard EF91 tubes. Moving the jumpers made me plenty nervous, but I managed without dropping the little jumpers inside the unit.

At first I really enjoyed the added presence in the bass and the clarity of the soundstage, but protracted listening led me to believe that these tubes are too aggressive and in the face, and ultimately a little bit rough and tiring to listen to.

Then I got a pair of Russian 6Sh1P-EV tubes from 1975. These were cheap, and they look very sturdy - they survived shipping from Hungary to the US wrapped in two napkins and put in a small bubble wrap envelope!

Anyhow, managed to switch back the jumpers without incident. The Russian tubes sounded good right away, and have a smooth detailed sound across the entire spectrum, with great bass extension and sound stage. I like these better than the original GE5654 tubes because of better bass and detail across the range. And of course the satisfaction of getting a bargain!

Have used them around 35 hours by now, and they are getting better, and just sound right.

Looking for two Mullard M8100/CV4010 to see what David likes, but haven't found these tubes yet conforming to the $8 rule.....

Man, this tube rolling is fun!

I've been listening to the new tubes for a couple days now and I'm not finding any brightness with these EF91's.  Mordy, I'd be curious to know your headphones and other equipment.  You may be getting brightness from elsewhere. 

Hello . I've recently just purchase and also received my LDMKIII . I have a question in which i hope some of you could help .

1) I'm currently using Xonar Essence STX as my DAC . How do i connect the LDMKIII to it ? I tried with the supplied RCA cable feeding it into spdif out but there's no sound .

2) I read around people saying that some tubes required jumpers and jumpers are included in the package but how do they look like ? Are they those small squarish pins packed together with the RCA cable ?

Thanks . 

Quote:

Originally Posted by x3dnd3x 

Hello . I've recently just purchase and also received my LDMKIII . I have a question in which i hope some of you could help .

 

1) I'm currently using Xonar Essence STX as my DAC . How do i connect the LDMKIII to it ? I tried with the supplied RCA cable feeding it into spdif out but there's no sound .

 

2) I read around people saying that some tubes required jumpers and jumpers are included in the package but how do they look like ? Are they those small squarish pins packed together with the RCA cable ?

 

Thanks . 

I have no experience with LDMKIII, but usually jumpers are small squarish pins you described:

Hopefully this helps
 

Been a while since I sold my LD but if I recall correctly the jumpers are for use with different tubes, but I also thought that there were now switches instead of the little jumper caps, so they aren't really necessary.  What tubes are you using?  If you don't roll tubes you don't have to worry about them and then only if you roll EF91, EF92  tubes, if I remember correctly.

As for your DAC you can't take the SPDIF out and run it into your amp.  That's a digital signal and your amp needs an analog signal.  You need to send the analog output from your DAC into the amp.

If you read the manual for the Little Dot MkIII it will tell you where the jumpers are. Underneath the amp towards the front are two oval holes.

Looking inside (it is best to use good light or a flashlight) you can see three little pins sticking up, with the jumper covering two of the pins. On one side it says EF95 and on the other side EF92. The little jumper looks like the little blue thing in the picture two posts ago. For EF95 tubes it covers pins #1 and 2, and for EF92 it covers pins #2 and 3.

The unit comes factory set for EF95 tubes. If you want to try tubes from the EF92 family you have to move the position of the two jumpers. Take a thin needle nose pliers and grab the jumper at the ends (not in the middle, because not using the length of the oval opening will not allow you to open the pliers big enough) and pull out gently. Then carefully push the two jumpers (one for each channel) onto pins #2 and 3.

It is a little delicate, and you cannot use any force since the components are fragile. Also remember to disconnect the amp and let it sit for 10 minutes before attempting any changes (in order for the capacitors to discharge).

I was worried about dropping the jumper inside the unit, but everything went well. Anyhow, I did not like the EF91/92 tubes, and I switched back the jumpers.

As far as I am concerned the experience was a little like going to the dentist, so I will try to avoid it again if I can and stick with EF92 types of tubes.

However, it did occur to me that somebody could make an inexpensive little gizmo similar to an automotive fuse puller that locks the jumper in it's grip, and then you don't have to worry about dropping it or losing it.

My power tubes keep burning out after a few months. I've heard this may be an issue with AC voltage supply. Here in Australia we have 240V and the amp is designed for 220V. I've heard that with this amplifier there might be an issue with that little bit of extra voltage stressing the power tubes.

Is this the issue I am having?

If so how can I fix it?

Contact David at Little Dot.  Look up their forum address.

I just bought some EF95/6AK5 at the recommendation of a poster on this thread. Sound great! Smoothed the vocals, opened the mids, I really see the effect tubes can have on an already great amp

Part of the fun with the MarkIII is how easy it is to change tubes and do some tube rolling. I am experimenting with different tubes, all the while trying to keep to the $8.00 rule - no tube should cost more than that, and preferably two for that price.

The best combination I found so far is to stick with the stock power tubes and use Russian driver tubes called 6Sh1P-EV. These I bought on E-Bay . The price was right, and they sounded good right away, and even better after burn-in.

I do not have the Mullard EF95 tubes yet, but this Russian tube is really good. It adds a whole new dimension to the sound. The bass is much stronger and has much more energy, and the entire sound spectrum  becomes fleshed out with a full bodied smooth sound. (Another name for this tube is 6J1P-EV)

I have compared them to the stock GE5654, Mullard EF91 and Western Electric 403A, and these Russkies win hands down.

I was worried about mine as my house voltage is usually 127 volts (or more).

Purchased one of these....

http://www.apc.com/products/family/index.cfm?id=67
 

It has a switch on the back for outputting 110, 120, or 127 volt regardless of incoming voltage and was around $40 (US). Anything like this available in Australia?

Quote:

Originally Posted by karn1911 

My power tubes keep burning out after a few months. I've heard this may be an issue with AC voltage supply. Here in Australia we have 240V and the amp is designed for 220V. I've heard that with this amplifier there might be an issue with that little bit of extra voltage stressing the power tubes.

Is this the issue I am having?

If so how can I fix it?

hello,

I´m new to tubeamps (and this forum).

I wonder if it´s really SO important to turn off the amp when connecting anything?

I.e. changing the source ... or plug in/off the cans.

I guess switching off and on won´t be that good either?

Before the MKIII i had (and still have) a small BravoV2 (mini tubeamp).

I always change or connect source and phones during power on and it´s still working fine ...well, let´s say it works - compared to the mkIII ;)

How do I recognize a large/full shield M8161? Are there any on Ebay right now?