[J.P.6]

I bought it second hand, I believe it is about a year old so will probably have jumpers.

 

[Max F]

I think they are going back to jumpers. Something about the soldering sometime melting the litte switch boxes during construction. I was posted by David on the little dot forum. I'm not sure if the new ones are already shipping with the jumpers though. I'm just happy I got the switches!

 

[ScottieB]

Ha yeah me too Max - getting to the switches is hard enough! I don't think my fat fingers would do too well with having to place jumpers in there!

 

[TubeStack]

Quote:

Originally Posted by J.P.6 /img/forum/go_quote.gif I got myself some Mullard EF92 (M8083) tubes the other day for my MK III when it arrives. They're both properly matched, NOS and the military version. Cost just over £10, pretty good I think. Does anyone use the upgraded jumpers? Worth getting?

I've got Mullard M8161s in my II++ and just order a set of two matched pairs for the MK III, when it arrives.

Are the stock power tubes that come with the MK III similar to the ones that came with the II++?

 

[J.P.6]

They are the 6C19 aren't they?

 

[dukja]

I have been waiting for the 6N6P to come from Ukraine since 4/7. The tracking shows that tubes arrive NYC on 4/11 and then has been sitting there for more than 10 days. Finally, the USPS tracking shows it is out of NYC facility today. Is it due to US customs or not?

Due to some power tube imbalance, I have been waiting for them for two weeks. It is really killing me.

On the other hand, both my Arietta and new M8083 came from Germany and UK in 8 days. Anybody has problem with shipping from Ukraine?

The new M8083 does sound like recommendation I got here: very close to SS sound: Clean, air, very spacious, and fast. It is very interesting experience changing from old EF95 to EF92 and now EF91. I have not compare them closely with either DT880 or HD600. When I got a good pair of power tube, definitely I'll report back the different sounding they have.

 

[Max F]

Yeah, those tubes from Ukraine start their journey buy horse and cart, I think. You should get them any day now. I think mine took 2 1/2 weeks. They are well packaged though and a great price!

 

[erikzen]

Just wondering how hot is too hot. I picked up a pair of EH power tubes. The amp definitely runs hotter now. Not so hot that I can't touch the faceplate, but it's very warm, whereas with the stock tubes it never felt hot. I never run these tubes for more than 3 or 4 hours, but is all the extra head damaging the amp or the tubes?

 

[erikzen]

I think this may have been my first double post.

 

[ScottieB]

Quote:

Originally Posted by erikzen /img/forum/go_quote.gif Just wondering how hot is too hot. I picked up a pair of EH power tubes. The amp definitely runs hotter now. Not so hot that I can't touch the faceplate, but it's very warm, whereas with the stock tubes it never felt hot. I never run these tubes for more than 3 or 4 hours, but is all the extra head damaging the amp or the tubes?

Can't answer your question, Erik sorry, except to say that my amp gets pretty hot even with stock tubes, and I just have a fan blowing over it which cools it way down, could be a simple solution.

But how do those EH tubes sound? One of my stock power tubes is on the fritz and I'm looking at replacement options...

 

[erikzen]

The EH tubes sound good - a definite improvement. They seem to give the amp more power. The sound just has more weight to it.

 

[Max F]

Mine get pretty warm but not too hot to touch. That would concern me. One thing I noticed is that even a ceilling fan makes a big difference in keeping it cooler. I have the MK-III with the 6N6P-i tubes.

 

[ScottieB]

So from what I've been told, using my low-impedance Grados with the LDMKIII puts quite a big load on the power tubes, and can cause them to wear out faster than using higher impedance headphones. It was recommended that I try an impedance adapter (around 200ohm) but I am having trouble finding one - ideally it'd use 1/4" jacks so I won't have to use adapters. Anyone know where I can find a good one?

 

[SemiAudiophile]

Quote:

Originally Posted by ScottieB /img/forum/go_quote.gif So from what I've been told, using my low-impedance Grados with the LDMKIII puts quite a big load on the power tubes, and can cause them to wear out faster than using higher impedance headphones. It was recommended that I try an impedance adapter (around 200ohm) but I am having trouble finding one - ideally it'd use 1/4" jacks so I won't have to use adapters. Anyone know where I can find a good one?

where'd you hear that? i use grado's with mine all the time.

 

[ScottieB]

David (the local LD guy, think he's the ebay seller), and then Prickly Peete - they said that with OTL amps, the load is much heavier on low impedance headphones. This was evidenced when I went to listen with my Grados the other day and was getting bad distortion from 1 channel. I narrowed it down to one of the power tubes. I'd never gotten distortion before - the tubes are maybe 9 months old. But I didn't get the distortion with my 300ohm Senns - so I emailed David and that's what he told me - said one tube was probably on its way out, but I didn't hear it with the Sennheisers because they don't require the tubes to work as hard. here's a quote from the email:

Quote:

For an OTL tube amplifier like the Little Dot MK III, the 300 ohm Senns are a very easy load, where as the the low impedance Grados are by comparison a more difficult load. If the power tube is on the cusp of going out, it would explain why you hear distortion with Grados and not with your Senns.

he's not saying you can't use the Grados, just that the tubes need to work harder with them - seems counter-intuitive to me, but I wouldn't know... a impedance adapter was recommended to prolong tube life.