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Little Dot MK VI / Little Dot MK VIII SE Owners Unite - Page 4

post #46 of 673
1/5/11 at 4:01pm

I received my MKVI+. Using it with RCA 6AS7G and RCA 5691 (red base). After only 10 hours I'm REALLY impressed !! By the far the best amp I have heard with the T1 (vs Phoenix , MAD Ear+HD, Goldpoint, Yamamoto HA-02, Burson, etc). It's the first time I can fully appreciate the T1 potential. 

 

Only problem is the buzz coming from one of the transfo ... 

 

I can't wait to hear how it will improve in the next 50-100 hours !

 

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post #47 of 673
1/5/11 at 5:09pm
Thread Starter 


Interesting, didn't try the red base RCAs yet, I have some Full Music 6SN7 (Sophia Electric) on the way though. And yeah, this amp really makes the T1 shine.

Quote:
Originally Posted by rattesp View Post

I received my MKVI+. Using it with RCA 6AS7G and RCA 5691 (red base). After only 10 hours I'm REALLY impressed !! By the far the best amp I have heard with the T1 (vs Phoenix , MAD Ear+HD, Goldpoint, Yamamoto HA-02, Burson, etc). It's the first time I can fully appreciate the T1 potential. 

 

Only problem is the buzz coming from one of the transfo ... 

 

I can't wait to hear how it will improve in the next 50-100 hours !

 

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post #48 of 673
1/5/11 at 8:36pm

frown.gif  Seems like no one is selling these used, but I wanna join the fun

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post #49 of 673
1/8/11 at 10:15am
Just ordered MK VI+ last week. How long it took to get your amp after order?
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post #50 of 673
1/8/11 at 12:01pm

It took three weeks to build and 6 days to be delivered (DHL Canada was closed for 2 days after Christmas so it would have taken 4 days I guess).

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post #51 of 673
1/9/11 at 11:52am
Quote:
Originally Posted by rattesp View Post

It took three weeks to build and 6 days to be delivered (DHL Canada was closed for 2 days after Christmas so it would have taken 4 days I guess).



That's really fast!  I may just have to bit the bullet and buy this guy brand new. Was hoping to pick one up used

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post #52 of 673
1/17/11 at 9:11am

As much as I like the amp, I might send it back for a refund. Too much problems for a brand new amp. First, the loud buzzing sound coming from the transfo, then the loud "rattling" noise coming from the fan (it's not a normal "fan sound"), now the auto-bias problem ... I've tried 3 different quads of power tubes, 3 pairs of driver tubes, it doesn't change anything : the right DC meter is always over 60 (between 65 and 70). I asked David if there is a way to manually adjust the bias and he said no. He didn't offer any explanation about the problem. I'm not really satisfied with the way David handles the problems. When I send an email, i ask 3-4 questions and he only answers to 1 or 2 questions !?!?! I have to ask a question twice before he replies. 

 

It's a great sounding amp but I think a got a lemon ???

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post #53 of 673
1/17/11 at 10:29am
Thread Starter 

You can replace the fans with silent ones, the previous owner of my amp did this for me. As for the tranformer, my right one buzzes a bit but it's hardly noticeable and it got better once I installed a AC filter. It's not wrong if one VU meter is off by around -5/+5 points from the initial value (6AS7G run on 60mA, 5998 on 40mA). My left meter exactly says 60mA while the right one is on 63mA. You won't hear the difference anyway and it also greatly depends on how well the quad is matched. Auto biasing seems fine here.

 

Do you hear the buzzing from your cans or from the outside? Only hearing it if I have my ears near it.
 

Quote:
Originally Posted by rattesp View Post

As much as I like the amp, I might send it back for a refund. Too much problems for a brand new amp. First, the loud buzzing sound coming from the transfo, then the loud "rattling" noise coming from the fan (it's not a normal "fan sound"), now the auto-bias problem ... I've tried 3 different quads of power tubes, 3 pairs of driver tubes, it doesn't change anything : the right DC meter is always over 60 (between 65 and 70). I asked David if there is a way to manually adjust the bias and he said no. He didn't offer any explanation about the problem. I'm not really satisfied with the way David handles the problems. When I send an email, i ask 3-4 questions and he only answers to 1 or 2 questions !?!?! I have to ask a question twice before he replies. 

 

It's a great sounding amp but I think a got a lemon ???

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post #54 of 673
1/17/11 at 10:41am

When I listen at low volume, I can hear the buzz from outside. The problem is that I use my headphones exclusively in bed and my girlfriend doesn't like to hear this loud buzz !!! lol !!

 

I've ordered new fans, hope it will help. David said it's ok to use it without fan if room temperature is below 27 C but even at 21C the amp gets REALLY hot.

 

As for the bias, thanks for the info. Hope it's normal and everything is ok. The meter is a mixed blessing since most auto-biased amp don't have them so you never know if the bias is slighlty wrong !!

 

I've ordered this power supply filter outlet from Audio-GD (http://www.audio-gd.com/Pro/amp/Power%20filter/PowerEN.htm ). I hope the DC filter output will help.

 

Thanks for your help ! You should work for Little Dot, you're more helpful than David wink.gif

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post #55 of 673
1/17/11 at 11:35am
Thread Starter 

You're most welcome. Like you said, most auto-biasing amps don't have a VU meter so you don't know whether the biasing is right or not. Since one of my meters is also off by a bit, I wouldn't worry about it. Some users reported that new quads were right off at 80mA and later biased themselves to 60mA. It's another thing if there's a huge difference between DC mA  like 30mA or more though.

 

I really wouldn't recommend to use the amp without fans as it gets quite hot and and decreases lifetime on the resistors and caps, even below 27 Celsius. As for the buzzing, I strongly believe that this is some sort of grounding issue, although I haven't heard other users complain about it before.

 

Could you perhaps do a recording of the buzzing?
 

Quote:
Originally Posted by rattesp View Post

When I listen at low volume, I can hear the buzz from outside. The problem is that I use my headphones exclusively in bed and my girlfriend doesn't like to hear this loud buzz !!! lol !!

 

I've ordered new fans, hope it will help. David said it's ok to use it without fan if room temperature is below 27 C but even at 21C the amp gets REALLY hot.

 

As for the bias, thanks for the info. Hope it's normal and everything is ok. The meter is a mixed blessing since most auto-biased amp don't have them so you never know if the bias is slighlty wrong !!

 

I've ordered this power supply filter outlet from Audio-GD (http://www.audio-gd.com/Pro/amp/Power%20filter/PowerEN.htm ). I hope the DC filter output will help.

 

Thanks for your help ! You should work for Little Dot, you're more helpful than David wink.gif

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post #56 of 673
1/17/11 at 2:03pm
Quote:
Originally Posted by reiserFS View Post

Could you perhaps do a recording of the buzzing?
 

 

ohhh yes, this please!
 

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post #57 of 673
1/17/11 at 5:51pm

I'll try to find something to record the buzz !

 

Concerning the right channel DC meter, I noticed that when the amp is off, it stays at 5-10 while the left one goes down all the way to 0. That probably explains why when the amp is on, the right meter is always at 65-70 !

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post #58 of 673
1/17/11 at 6:11pm
Thread Starter 

Seems like the meter itself is at fault then and not the biasing.
 

Quote:
Originally Posted by rattesp View Post

I'll try to find something to record the buzz !

 

Concerning the right channel DC meter, I noticed that when the amp is off, it stays at 5-10 while the left one goes down all the way to 0. That probably explains why when the amp is on, the right meter is always at 65-70 !

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post #59 of 673
1/18/11 at 7:58pm
Hello guys , I have the same Problem with the transformer hum and the fans. My MKVI is about 2 months old and it already been to china and back.
I also have a problem with my single ended out it has this crazy noise , like electronic interference.
The amp sounds amazing , that is why I got it. My friend Audiogalore has one of the older MKVI and we compared it to the wa22 , the balancing act and wa6 SE and it sounded much better than all of them. It is just an amazing sounding unit and I think it is worth the headaches.
Edited by che15 - 1/20/11 at 4:00pm
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post #60 of 673
1/23/11 at 7:31am

Hi everyone,

 

Can't wait to use the amp, as am waiting for the DAC to arrive in a couple of days Is there a burn in time for the amp?

 

On the instructions it talks about burning it in the amp, and I was wondering how long does it take?

 

Also, I got some valves to replace the stock ones - I gather these don't need burning in time?

 

Thanks!

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