Review of the Little-Dot MKIII Tube Headphone Amp/Pre-Amp

[ethebull]

The only thing I can think of to check is the outer shells of all four plugs in play. Many thread on and establish the location of the stop point for insertion (that sounds dirty)

Check that all your phono plug shells are nice and snug.

If they are, either experiment with another adapter, cut off and replace the mini-jack with a HQ 1/4", or fashion a washer spacer to slip over the jack so that it inserts to the right place every time.

[Penchum]

Originally Posted by batmanwcm

Hey ethebull,

I just came back from the store. OK, I have finally isolated the problem. I have MS1's and IM716's. I now have two 3.5mm-> 1/4 jack adaptors. If I plug either headphones all the way in, in either adaptor, there is only sound coming from the left channel. However, if I pull out the headphone jack a little bit, I get sound coming from both channels. This is weird. Anyone know what is going on?

It is possible there is corrosion on the contact tab in the jack. Usually, this will go away with repeated plugging and unplugging of the plug (power off). It's usually when the tip of the plug contacts the surface of the tab. Look at the plug's tip. Clean it if necessary and do some ins and outs.

[batmanwcm]

OK, I just bought a 3rd adapter. I plugged in either my MS1's or IM716 with all 3 different adapters to my Yamaha receiver and both channels work with all the adapters with no problem.

I'm starting to believe this is a jack issue with the MKIII. I'm going to keep trying.

[Penchum]

Originally Posted by batmanwcm

OK, I just bought a 3rd adapter. I plugged in either my MS1's or IM716 with all 3 different adapters to my Yamaha receiver and both channels work with all the adapters with no problem.

I'm starting to believe this is a jack issue with the MKIII. I'm going to keep trying.

Maybe you can look inside the jack with a flashlight and see if everything looks new and normal? The only times I've ever heard of this happening, was due to corrosion, or a bent jack tab that doesn't spring properly any more.

[batmanwcm]

After testing this thing all day, I'll explain what's going on. I drove over to my friend's house and borrowed his headphones. His cheapie Acoustic Research headphones have a 1/4 jack so it doesn't need a adapter. After the amp is cold, whenever I start the amp, the sound is extremely low (past 2 o'clock mark), even at the highest gain settings. However, after about 5-10 minutes of warm up, the sound will get extremely loud in the left channel and no sound will come from the right channel even though I did'nt touch the volume knob. Afterwards, I tried using the adapters and my MS1's and IM716's and duplicated the same problem. I'm really at my wits end here.

I've emailed Dave so hopefully he will take care of it.

[Mike_TNT]

Noob questions part 2:

a) Just to confirm, the LD suffers from a slight channel imbalance on extremely low volume setting right? I can hear music coming out from the right channel when the volume knob is at 0 but when I move it up a notch or two everything seems fine.

b) For the amp to burn in, do I need to have music playing through it or can I just leave it powered on without having any signal go through it? Also, do headphones need to be plugged in for the LD to burn in?

c) I got some Russian 6ZH1P-EV and Mullard M8161 on the way. For the the Mullard's I'll need to install 2 jumpers right. I just have to insert them in the back and that's it?

d) Is a power chord upgrade for the LD worthwhile?

Thanks all.


Maybe a LD mkIII FAQ would be in order.

[hendry]

i use DIY power cord and marigo power cord, both make sounds of my MKIII good, more punchy, more detail, more warm in mid

[Penchum]

Originally Posted by Mike_TNT

Noob questions part 2:

a) Just to confirm, the LD suffers from a slight channel imbalance on extremely low volume setting right? I can hear music coming out from the right channel when the volume knob is at 0 but when I move it up a notch or two everything seems fine.

b) For the amp to burn in, do I need to have music playing through it or can I just leave it powered on without having any signal go through it? Also, do headphones need to be plugged in for the LD to burn in?

c) I got some Russian 6ZH1P-EV and Mullard M8161 on the way. For the the Mullard's I'll need to install 2 jumpers right. I just have to insert them in the back and that's it?

d) Is a power chord upgrade for the LD worthwhile?

Thanks all.


Maybe a LD mkIII FAQ would be in order.

a). Usually only when new and not "matured" yet. The high gain setting plays on this too. Not to worry, just do the hours and everything will be good to go.

b). You need to supply a source and a load for the amp to drive, so yes, you need to play music (MP3 player on repeat would work nice) and drive the headphones too. Remember, no more than 8 hours a session, cool to room temp before starting the next 8 hour session.

c). Yes, do the jumpers when using EF92 family tubes. I use a pair of needle nose pliers to install them through the access holes in the bottom of the amp.

d). Back a ways in this thread, is a small review of a power cord that I like very much. It is only $10, and is very well built.

[Penchum]

Originally Posted by batmanwcm

After testing this thing all day, I'll explain what's going on. I drove over to my friend's house and borrowed his headphones. His cheapie Acoustic Research headphones have a 1/4 jack so it doesn't need a adapter. After the amp is cold, whenever I start the amp, the sound is extremely low (past 2 o'clock mark), even at the highest gain settings. However, after about 5-10 minutes of warm up, the sound will get extremely loud in the left channel and no sound will come from the right channel even though I did'nt touch the volume knob. Afterwards, I tried using the adapters and my MS1's and IM716's and duplicated the same problem. I'm really at my wits end here.

I've emailed Dave so hopefully he will take care of it.

I shouldn't try to guess on this, but this sounds very much like the first bad tube took out one of the resistors. I'm sure DavidZ will fix you right up. He's been so excellent in solving any issues and getting folks up and running fast, so hang in there and let us know what you do next.

[Mike_TNT]

Originally Posted by Penchum

a). Usually only when new and not "matured" yet. The high gain setting plays on this too. Not to worry, just do the hours and everything will be good to go.

b). You need to supply a source and a load for the amp to drive, so yes, you need to play music (MP3 player on repeat would work nice) and drive the headphones too. Remember, no more than 8 hours a session, cool to room temp before starting the next 8 hour session.

c). Yes, do the jumpers when using EF92 family tubes. I use a pair of needle nose pliers to install them through the access holes in the bottom of the amp.

d). Back a ways in this thread, is a small review of a power cord that I like very much. It is only $10, and is very well built.

Excellent! Thanks a lot P. It turns out that I have much less burn in time than I thought.

I have an "audiophile" power chord terminated with a Marinco plug and I did a stupid thing by plugging it into the LD without securing the weight. Now the plastic cover that's over the AC input and the on/off switch got a bit loose. Hope everything is alright inside.

[Penchum]

Originally Posted by Mike_TNT

Excellent! Thanks a lot P. It turns out that I have much less burn in time than I thought.

I have an "audiophile" power chord terminated with a Marinco plug and I did a stupid thing by plugging it into the LD without securing the weight. Now the plastic cover that's over the AC input and the on/off switch got a bit loose. Hope everything is alright inside.

Mine is a little bit loose too, I think it is a snap-in design (not sure) so it shouldn't fall out or anything like that.

[Mike_TNT]

Originally Posted by Penchum

Mine is a little bit loose too, I think it is a snap-in design (not sure) so it shouldn't fall out or anything like that.

Great! I worry too much about my baby.

[NikZ]

Hi , is this wonderful amplifier still available for buying? I notice "out of stock" message on the little-tube website. Does it come with rca cables or do I have to supply my own cable?

[batmanwcm]

Originally Posted by Penchum

I shouldn't try to guess on this, but this sounds very much like the first bad tube took out one of the resistors. I'm sure DavidZ will fix you right up. He's been so excellent in solving any issues and getting folks up and running fast, so hang in there and let us know what you do next.

I shipped the amp to Dave using a Ohio address. Hopefully they send my replacement out ASAP. So far, great customer service on their part. I'll update once I get my replacement.

[batmanwcm]

Originally Posted by NikZ

Hi , is this wonderful amplifier still available for buying? I notice "out of stock" message on the little-tube website. Does it come with rca cables or do I have to supply my own cable?

They should still have supply left since they have an ebay auction up.
eBay Link to MKIII

Just email Dave at little.tube@gmail.com to order directly.