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Little Dot MKIII Tube Rolling - Page 118

post #1756 of 3153
All I can say, Lars, is that while you are enjoying listening to your amp, read the previous 116 pages of this thread. It will answer all of your current questions and more.
post #1757 of 3153
Hi LarsP. Welcome to Head-Fi. Sorry about your wallet!

I don't know of any guide with images or video but there is a tube FAQ on this site.


Despite a few broken links it is chock full of useful information.

In general, handle tubes with care. They are glass after all and will break if they are dropped or mishandled. Also, sudden movements can sometimes damage the internal circuits. I would say however that tubes, at least the driver tubes for the LD MKIII are not particularly fragile. Handle them with reasonable care and you will be fine. Of course there are some tubes out there that cost hundreds of dollars and those should be handled appropriately. Fortunately, there are a lot of tubes available for the LD MKIII that aren't super expensive especially if you aren't overly concerned with original boxes and having matched pairs. Although peoeple put a lot of emphasis on tube matching, I've put two brands in my amp at the same time and didn't hear any problems. Keep in mind we're sometimes trying to squeeze out the last 1% of sound quality. Whether or not matching tubes is important to you is a personal decision and only experience will let you know if it matters to you. That being said, I just paid $50 for a matched pair of Mullard 8100s. Hey, you've got to have a least one set of expenisve tubes, right?

Also, clean any deposits on the glass as they will heat and cool at different rates than the tube itself stressing the glass. Eventually the tube could crack. This means avoid touching the glass envelope as much as possible and consider using cotton gloves or a cloth when handling tubes, especially your more expensive ones.

In terms of inserting and removing tubes, use a gentle rocking or rotating motion (hence the term "tube rolling") to ease the tubes in and out of their sockets. Never push down or pull up directly, as this could cause the pins to bend or tube to break.

As far as actual tube recommendations this thread, although now getting somewhat huge and difficult to manage, is filled with recommendations. I personally have a variety of tubes but am still learning their nuances. From what I've heard so far, I would recommend either the Mullard 8161 or the Western Electric 403B although I don't have the HD650 so take it with a grain of salt. The 8161 is an EF92 variant so you will have to switch the jumpers on the bottom of your amp if you get them.
post #1758 of 3153
I agree.
post #1759 of 3153
Hey everyone, i have some EF91s I got (mullard 6aw6's if i'm not mistaken) and I'm having trouble finding this switch that the manual of the MK3 refers to. I see jumpers, but I bought this thing used and it didn't come with any sort of jumper. Does that mean I'm SOL? Can anyone post a picture of their jumper or their mk3 with one in it? Thanks!
post #1760 of 3153
You either have switches or jumpers. The switches should be obvious - just like the switches for setting the gain.

If they are jumpers then if you didn't get the little metal jumpers with your amp, you can find them at a electronic supply store or computer repair store.
post #1761 of 3153
Thanks Max_F
post #1762 of 3153
Actually, if you still have the bag that contains the RCA cable that came with the amp - I think it has the jumpers in it. I never checked mine since I already had a cable and my amp came with switches.
post #1763 of 3153
hmm how do you remove the EF92 jumpers on the LD MKIII? I tried tweezers but i can't reach in. Do i need to open the casing? I have some Ef95 tubes i want to try out.

edit: turns out my LD has NO jumpers this whole time and I was using EF92 tubes? How did it not break something? :P Weird...
post #1764 of 3153
Originally Posted by PascalT View Post
hmm how do you remove the EF92 jumpers on the LD MKIII? I tried tweezers but i can't reach in. Do i need to open the casing? I have some Ef95 tubes i want to try out.

Long skinny needle nose pliers work ok or if you know someone in the medical field an old pair of hemostats work great.Dentists use them alot and you may be able to talk them into giving you an old pair.....You can also pick up the hemostats in the fishing dept of Walmart too I believe.....Try to get the longest ones you can find.....If you think the LD MKIII is difficult, the LD MKIV is harder still
post #1765 of 3153
Mine has switches (thank goodness!).
post #1766 of 3153
edit: I fixed the problem. Turns out the stock LD tubes are Ef95.. I thought this whole time I was using/buying EF92 tubes...

I'm really loving these WE403b tubes. The boxes say they were made in April 1974.

After trying 3-4 different sets of tubes and not being too happy, I think I'll stick with these for a while. They opened up the sound a lot, it sounds clearer and the sound stage is wider, the tubes also tightened up the bass which is exactly what I was looking for.

There's more on ebay if anyone is interested: http://cgi.ebay.ca/ws/eBayISAPI.dll?...m=350169775886 You gotta ask them to match the tubes if you want.
post #1767 of 3153
Update on the Mullard "Valve Electronic CV4010 KQDD/K"

The tubes definitely tightened up! These are some sweet tubes. In my top 3.

One thing that I've noticed with tube burnin is that the bass is what changes the most. Usually it gets stronger and tighter. You can tell alot about the sound of the tube from the get go as far as the soundstage, mids and highs are concerned. The bass tends to come in later. Just and personal observation.
post #1768 of 3153
Originally Posted by Max F View Post
Update on the Mullard "Valve Electronic CV4010 KQDD/K"

The tubes definitely tightened up! These are some sweet tubes. In my top 3.

One of my favorites also. It just does everything right.

I got some new tubes from Tube World today. I thought I would splurge one last time and get some matched pairs.

I picked up a pair of Raytheon JRP-6AK5W "anchor" tubes 1952 and a pair of Mullard Whyteleafe plant M8100 1958.

Since I have a couple of other Mullard tubes, the first thing I wanted to try were the Raytheons. Listening now for a few minutes the highs are very rolled off. The music has warmth but lacks sparkle and detail. The sound is very "soft" for lack of a better term. Maybe smooth would be a better term. I hope these open up a bit over time.
post #1769 of 3153
I just put a list of my tubes together. Geez, the numbers start to creep up on you.

I now have 17 pairs of tubes. A lot of them are just odd tubes that I picked up on eBay. So I only have a few matched pairs.

GE 5654 - These are the ones that came with the amp. I assume they're matched but they might not be.

Mullard CV4010/M8100 1980 black plates
Mullard EF95 Whyteleafe Plant
Mullard M8161/EF92/CV4015
(OK I think I have that brand covered)

RaytheonJRP-6AK5W 1952 black plates, D getter, Navy anchor symbol
Voshod 6J1P-EV 1981 black plates, ribbed glass, halo getter, military rocket symbol
Tung Sol 6AK5W 1957 grey plates, square getter (dealer said it was a matched pair but markings on tubes are not completely identical.)

I've got a few unmatched pairs as well:
Amalgamated Wireless 6AK5W - 4 pairs
Western Electric 403B - 3 pairs
Amperex 5654

Then I have some odd GE, Motorola and RCA tubes.

34 in all.
post #1770 of 3153
I just got a used LD III with stock Russian power tube and Mullard 8100. I have been told that the power tube had more than 1000 hours and drive tube about 600 hours.

comparing it with V-DAC > Arietta >DT880, I found LD had softer and easier higher mid. However Arietta sounds much cleaner, better clarity, and revealing of multiple layers of sound stage. LD sounds like multiple sound sources are squeezed into a "wall" (Is it what people called wall of sound?)

So I would appreciate your experience to see if those tubes need to be changed and your recommendation to get better spatial resolution. After reading many pages, I wasn't able to get any conclusion yet.

Many thanks!!
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