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The Little Dot Mk IV / SE Appreciation Thread - Page 4

post #46 of 420

My MK IV SE arrived Friday, but sadly it's been plagued with a problem I'm unable to pin-point. The first evening of firing it up I enjoyed a listening session of sonic bliss. Even straight-out-of-the box - with an also brand new HD 650 and source (the Little Dot DAC_I) - the sound was very impressive. It was more engaging, alive, detailed and realistic compared to anything I'd heard up until this point - this is the closest I've ever come to feeling like I'm listening to a live performance from audio equipment.

 

However, the next morning - eager to repeat the experience - I fired the amp up and left it playing to warm-up and continue the burn-in while I went about the morning's duties. Upon putting the phones on my head to settle down to another listening session, I could hear a very clear rustling/crackling/squeaking sound coming from the left channel. I could hear this noise with the volume set to 0 and the source turned off. I wasn't too worried initially, I'd read many accounts of tube pins becoming oxidised during transit, and so got to work cleaning all tube pins with isopropyl alcohol. This didn't solve the problem, so I decided to try swapping the tubes around (driver first, power second) so see if I had a dodgy tube. I also checked the gain switches and moved them back and forth several times. None of this made a difference either.

 

To cut a long story short, I repeated swapping tubes and moving the gain switches a good number of times to try to pin-point the issue. During this trouble-shooting, the issue moved to the right channel and then back to left, however I have never heard the noise from both channels during the same listening session. I have also been unable to identify a gain switch or tube as the cause, because while the issue did move back and forth channel, it does not move with the adjustment/re-positing of any of these components. I have followed literally every recommendation in the troubleshooting guide (swapped fuse, power plug, checked tube jumper position and turned off all electrical equipment in vicinity and moved the amp to a different location), I've also tried the HD 650 in a different amp and used a different source with the MK IV to be sure.

 

Today I purchased some electrical contact cleaner to clean the tube pins, sockets and gain switches as I understand this can be more effective at cleaning electrical components than isopropyl alcohol. I've been in touch with David who directed me to follow the trouble-shooting guide but hasn't offered any other suggestions so far. If the contact cleaner doesn't do the trick (I'm doubtful it will as the tube pins look clean to me), then I see no alternative than to send the amp back, and I'll be insisting Little Dot pay postage.

 

If anyone has any further ideas or tricks I'd be grateful to hear them. I'm loathed to send the amp back, as after hearing its potential, I'm really keen to start enjoying it.

post #47 of 420

jr, I suggest you clean the pins using wire wool.

To me it sounds like a tube problem.

You could have 2 bad tubes so when you swap them over the problem doesn't go.

Another option would be to buy a couple of cheap but tested drivers (Mullard M8100 as you're in UK) and see if that solves the problem.

Good Luck 

post #48 of 420

The contact cleaner hasn't worked. I'll try wire wool, thanks for the suggestion.

post #49 of 420

I tried wire wool, but that didn't make a difference (although it did clean the pins up noticeably). I then swapped the driver tubes into my Little Dot MK I+ (I really should have thought of that sooner!) and could hear no interference at all. As such I e-mailed David and he's supplied me with return details and offered to pay the shipping fee.

post #50 of 420

I'm sorry to hear about your situation - it's hard enough to wait for something like this in the first place. This is my third LD product and I've never had a problem (knock on wood) - but David seems to be a fair person who cares about his customers so I'm sure he'll make it right and I hope you are in business soon.

 

On another note - I'm currently running some GE 5-Stars is my MKIV and they really have what I would describe as a detailed SS - not as warm/tubey as the EF91/92s - but really powerful and tight in the lows which match well with my DT990s. Great tube - you need to shop around and find a reasonable price on eBay because many LD MKIII owners seem to favor these and they tend to be over-priced.  
 

Quote:
Originally Posted by jr41 View Post

I tried wire wool, but that didn't make a difference (although it did clean the pins up noticeably). I then swapped the driver tubes into my Little Dot MK I+ (I really should have thought of that sooner!) and could hear no interference at all. As such I e-mailed David and he's supplied me with return details and offered to pay the shipping fee.

post #51 of 420
Thread Starter 

My customised volume knob. Nice?

 

Mirror(polished) finished. Incredibly reflective. This knob is heavy as it is made of solid brass and plated in Gold. Feels solid! The weight gives a really good feel when turning the knob.

 

 

Mk-IVse-gold-knob.jpgmk-IV-goldknob-2.jpg


Edited by Tiramisu515 - 10/4/10 at 7:31pm
post #52 of 420

Very nice!

post #53 of 420

Nice indeed. I see you also changed the screws from black to silver on the Neutrik lock on plug

post #54 of 420
Thread Starter 
Quote:
Originally Posted by .Sup View Post

Nice indeed. I see you also changed the screws from black to silver on the Neutrik lock on plug


indeed, and also changed the screws of the MK IV face plate to silver. smily_headphones1.gif


 

post #55 of 420

Very classy!

post #56 of 420
Thread Starter 
Quote:
Originally Posted by jr41 View Post

I tried wire wool, but that didn't make a difference (although it did clean the pins up noticeably). I then swapped the driver tubes into my Little Dot MK I+ (I really should have thought of that sooner!) and could hear no interference at all. As such I e-mailed David and he's supplied me with return details and offered to pay the shipping fee.



Hi Jr41,

What is the status of your amp now. Have you send it back to David for a replacement?

 

Keep us updated smily_headphones1.gif

 

Tiramisu515

post #57 of 420


I shipped the amp back to Little Dot on Friday last week. It probably won't get to them until some time next week. David advised testing/repair/replacement could take up to three weeks, and then it's got to be shipped back of course. So I'm probably going to be without my amp for some time yet. I'm glad Little Dot agreed to pay return shipping as the cost was £65! I can't believe how much UK international shipping charges are.


I'm burning the HD 650 in on my Little Dot I+, but it's no way near the same (not to take anything away from the I+, it's a budget amp). Although my time with the MK IV SE was brief I'm missing it very much.


I may research and buy a few different, well regarded, driver tubes for the MK IV in the interim to keep me occupied. The I+ and IV SE are able to share a lot of the same tube types, which is a bonus.

Thanks for your interest and I'll keep you abreast of developments


Edited by jr41 - 10/7/10 at 12:32am
post #58 of 420

Hope it gets back asap, meantime enjoy your LDI+.

post #59 of 420
Well, I switched the internal jumpers today to the EF91/92 tube setting and rolled in my favorite Mullard EF91 Blue Glass tubes so I'm looking forward to enjoying these for a while. Not easy to get at the jumpers, a bit of a pain actually. I used tweezers, but I think a pair of hemostats may be the tool of choice.

I have been listening to my DT990s and they sound fantastic. I'm getting the itch maybe to get the DT880s, any comments on the Beyer DT880s paired with the MKIV from anyone?
post #60 of 420

I have used the DTE880/250Ohm and they are not that bad.

My preferred cans at the moment for the LD MKIVSE are the HD650.


Edited by rosgr63 - 10/10/10 at 10:38pm
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