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Little Dot MK VI / Little Dot MK VIII SE Owners Unite - Page 82

post #1216 of 1405

Hi,

 

I need some advice. Inow have the 8 x 330 Ohm resistors for the Little Dot MK VI+. I have removed the base plate, the volume knob and nut and washer, and removed 8 Philips Head screws from the circuit board. But the circuit board is not wanting to move. It seems to be still stuck down in the middle section, right beside the burnt resistor. Have I gone blind and missed a couple of screws? Is there something else I need to do? Do I need to remove the transformer covers?

 

I hope one of you people who have already disassembled a Little Dot MK VI+ can offer me some advice, and help me to get the circuit board out of the chassis. Thanks.

post #1217 of 1405

OK I was going blind, I found 2 more Phillips head screws (under the large capacitors) and now the circuit board is loose, able to move a few millimetres, but not enough to get it out. There seems to be a lot of wires attached to it and I am not sure how to get the board out.

 

Can anyone offer me advice? Please. 


Edited by ozaudios - 3/11/14 at 8:42pm
post #1218 of 1405

OK, WIGGLE WIGGLE WIGGLE, OUT

 

The sound is better than ever!!!!

 

This is a worthwhile upgrade!!!

 

It sounds SO SWEET. Prefect balance is back, super detailed, warm and wonderful.

post #1219 of 1405

Well done.

Releasing the PCB was the hardest part for me too.

 

I'm now asking myself maybe we must change every single resistor in the amp... ?

 

Coupling caps + 8 Kiwame is indeed an outstanding upgrade. I recommand everyone not to sell the amp without giving it a try : it'll reward you with something you don't even imagine.

post #1220 of 1405

 

I removed the 2 aluminium rings that usually surround the base of the driver tubes. This allows me to use my favourite driver tubes without using socket savers to get them to fit inside the aluminium rings. So the gold plated pins plug straight into the amplifier, which has to be better than going through the cheap nasty steel pins of the socket saver.

 

Thanks G600 for the information about which resistors to replace, and for letting me know about the KIWAME resistors. They are a good quality product. They work well with the other parts in the Little Dot MK VI+.

post #1221 of 1405
Quote:
Originally Posted by ozaudios View Post

I removed the 2 aluminium rings that usually surround the base of the driver tubes.

 

Not a bad idea !

 

Quote:

 

Originally Posted by ozaudios View Post

Thanks G600 for the information about which resistors to replace, and for letting me know about the KIWAME resistors. They are a good quality product. They work well with the other parts in the Little Dot MK VI+.

 

My pleasure. There are other brands of good resistor. But Kiwame are nicely built (carbon film inside ceramic) and relatievely inexpensive.

 

I'll also check the other cheap metal film ilside the amp and maybe replace them aswell...

Maybe tantalum for signal path...

post #1222 of 1405
Quote:
Originally Posted by G600 View Post

 

Maybe tantalum for signal path...

 

Avoid tantalum like the plague. 

 

The only resistors I would replace would be for power supply (i.e big 5 watt power resistors present in the amp) or the resistors next to the Philips BC axial's. 

 

You can replace everything in the amp if you want but a waste of money which some areas have no gain.

post #1223 of 1405

Ok.

That's my problem : I don't know what is critical and what's not in the amp...

post #1224 of 1405
Quote:
Originally Posted by G600 View Post
 

Ok.

That's my problem : I don't know what is critical and what's not in the amp...

Anything that is critical is usually in pairs or quads. 

post #1225 of 1405

Everything went well for a couple of hours, the amp sounded better than ever....... then a loud crackling sound.......... then the gauges went to max, and the sound stopped, and the room filled with the smell of burnt electronics (magic smoke) and now the amplifier is dead!

 

RIP LITTLE DOT MK VI+!

 

I spent over $1000 on this amp, looked after it like a baby, and it is only 8 months old. The burnt resistor was affecting the sound quality and the balance, and that is entirely the fault of the design and builders of the amp. I did not do anything to burn a resistor. And now (because shipping to China with insurance costs hundreds of dollars, just shipping them a few capacitors cost me $100 in postage) I have tried to fix the burnt resistor myself, so the warranty is void, and now the amp is cooked. 

 

So $1000 for the amp, $200 for the capacitors, $100 for postage of the capacitors to China.......... $1300 for an amplifier that lasted 8 months. Not at all good value for money. I see the main problem as being the heat issue, the circuit board enclosed in an aluminium chassis, very close to the tubes, getting very hot all the time. Nothing can cool the amp properly. 

 

The sound this amp makes is amazing, but if it is cooked in less than a year it is not worth the cost. I wish I had waited a bit longer and bought a good British amplifier, with a local dealer and no need for me to pay hundreds of dollars for shipping to have anything repaired. I could not recommend this product to a friend. 

 

I will look for a local electronics expert to diagnose the problem, see if I can get it fixed. Even that could cost me hundreds and the amp could just do the same again...... cook another component and fail to work again. 

 

Now I want to build my own amplifier, point to point, and use better parts (not ten cent resistors) and design it to cool properly. 

post #1226 of 1405

Oh my god ! :(

 

You mustn't stop here, just ask somebody to diagnose what's wrong !

It may be a transformer issue or something like this ? Don't forget there are 2 fuses, maybe they took their duty ?

post #1227 of 1405
Ah what a shame!
post #1228 of 1405

Really sorry to hear that, it's way above my pay grade but I certainly hope you manage to salvage something from the wreckage especially as it was sounding so promising. It can only get better from here......

post #1229 of 1405

Email sent to David at Little Dot......NO REPLY.

 

I contacted a local repair shop that works on tube amplifiers, they NEED a circuit diagram to work on the amp.

 

Looks like it is time to buy a WOO AUDIO WA22, at least their warranty is actually worth something. 

post #1230 of 1405

There is nobody else to blame but yourself due to the mods you performed yourself. Electronics don't die randomly, there is a sole reason for it.

 

Sorry for your loss. 

 

But if you post pictures of the PCB myself and the rest of the community here can help identify, mitigate and fix the problem your amp has experienced.

 

Or go the expensive route and get it checked by a qualified tech.

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