[liupublic]

Just picked an used mk IV SE. Very good pairing w hd650. Selected gain setting of 5db. Vol control is now at 10-11 o'clock for my lessening vol. is this about what I should expect? The menu suggested 10db setting but I think that is a bit too much gain.

Recv 3 sets of driver tubes plus original power tubes. Gonna spend the next few weeks on testing.

Ipod 160gb 7th gen -> pure I-20 -> cambridge dacmagic 100 -> LD IV SE -> senn hd650

 

[TrollDragon]

Congrats and welcome to the Club!

I use a gain of 5 with my MK IV and the DT880 Pro's, volume around 10-11 as well.

A gain of 10 just got too loud too fast and if you plug in some some headphones with higher efficiency, I found 9 o'clock too loud.

Good to see you have some spare tubes as well, check out the Little Dot Tube Rolling Thread, Page 77 has a table with all the B7G tubes you can use as drivers.

One of the best driver tubes we have found for an unmodifed LD is the 6HM5, they are really worth checking out.

http://www.ebay.com/itm/6HM5-6HA5-EC900-export-quality-audio-triode-tube-NOS-FREE-SHIPPING-/300879467071

 

[liupublic]

LD IV SE definitely have much more drive than my other tube headphone amp.  
 
I still have an older Mapletree.  My last headphone AKG Q701 was a good paring with Mapletree.  I think Sennhesier HD650 matches better with LD IV SE.  
 
Probably tube roll with what I have now for 4-6 weeks and then move on from there.   

 

[bbmiller]

 
I have two questions.
 
Do any of you know another name or description for the jumper circled above in the picture? I seem to have misplaced the ones that came with my amplifier and although I probably could contact little dot and get more I would like to do a search on eBay and Amazon first so do any of you have a search terms for those little black things that you think would work? Unfortunately just a words PCI jumpers do not work.
 
Secondly I thought the little dot IV amplifier was a hybrid, but in a recent review it seemed to be reviewed as a tube amplifier was the suggestion you could buy a little dot hybrid if you needed an amplifier for low impedance headphones which might work just as good. Consequently I looked at all the pictures of the circuit boards closely and only seen to see one bridge as a solid-state component.
 
 
So is this really a tube amplifier and if so do any of you who rolled tubes experience any noise with any of them? With my 300 ohm Sennheiser HD 600s I am experiencing absolutely no noise at any volume levels with the stock se tubes.

 

[MIKELAP]

 
 
I have two questions.
 
Do any of you know another name or description for the jumper circled above in the picture? I seem to have misplaced the ones that came with my amplifier and although I probably could contact little dot and get more I would like to do a search on eBay and Amazon first so do any of you have a search terms for those little black things that you think would work? Unfortunately just a words PCI jumpers do not work.
 
Secondly I thought the little dot IV amplifier was a hybrid, but in a recent review it seemed to be reviewed as a tube amplifier was the suggestion you could buy a little dot hybrid if you needed an amplifier for low impedance headphones which might work just as good. Consequently I looked at all the pictures of the circuit boards closely and only seen to see one bridge as a solid-state component.
 
 
So is this really a tube amplifier and if so do any of you who rolled tubes experience any noise with any of them? With my 300 ohm Sennheiser HD 600s I am experiencing absolutely no noise at any volume levels with the stock se tubes.

i run a pair of hd 800 and no noise also but  i had a few noisy tubes tough and its a tube amp suppose to work better with high impedance but i used a pair of 25 ohms Denon and it sounded good but i use them mostly with a low output impedance amp with better results .

 

[TrollDragon]

 
 
I have two questions.
 
Do any of you know another name or description for the jumper circled above in the picture? I seem to have misplaced the ones that came with my amplifier and although I probably could contact little dot and get more I would like to do a search on eBay and Amazon first so do any of you have a search terms for those little black things that you think would work? Unfortunately just a words PCI jumpers do not work.
 
Secondly I thought the little dot IV amplifier was a hybrid, but in a recent review it seemed to be reviewed as a tube amplifier was the suggestion you could buy a little dot hybrid if you needed an amplifier for low impedance headphones which might work just as good. Consequently I looked at all the pictures of the circuit boards closely and only seen to see one bridge as a solid-state component.
 
 
So is this really a tube amplifier and if so do any of you who rolled tubes experience any noise with any of them? With my 300 ohm Sennheiser HD 600s I am experiencing absolutely no noise at any volume levels with the stock se tubes.

The circled item is a standard PC board jumper that you could pic up from any computer repair shop.
Here are quite a few on eBay with handles -> LINK <- that make them easier to grab with tweezers or a pair of hemostats.
 
The MK II III IV are all OTL Tube Amplifier's with the only major solid state component being the bridge rectifier. The Little Dot I+ is a hybrid (Tube & Opamp).
 
Some tubes can be noisy, some microphonic and some don't make any noise at all, it is a roll of the dice when you buy tubes.
 
My 35Ω Ultrasones have a moderate hum when I plug them into the MK IV, I use an DIY Impedance adapter to bring them up to 150Ω's which reduces the hum to a very minimal level.

 

[bbmiller]

 

i run a pair of hd 800 and no noise also but  i had a few noisy tubes tough and its a tube amp suppose to work better with high impedance but i used a pair of 25 ohms Denon and it sounded good but i use them mostly with a low output impedance amp with better results .

If you really think the little dot IV se is adequate for those expensive HD 800s and have heard them with other amplifiers that's impressive? I heard the HD 800s are notoriously hard to drive. I myself am waiting for CanJam @ RMAF to hear my first other audiophile grade equipment. I am very impressed with the sound of my little dot IV se which just the stock tubes right now, but will be very interested in seeing if I could hear better sound through my HD 600s with other amps, and what ever, with the same music and singing I am impressed with at home.

 

[bbmiller]

Originally Posted by TrollDragon /img/forum/go_quote.gif
 
Some tubes can be noisy, some microphonic and some don't make any noise at all, it is a roll of the dice when you buy tubes.
 
 

Does that mean I can buy the same stock tubes again and get noisy ones? Is noise more related to tube type or the individual tube you get?

 

[TrollDragon]

Does that mean I can buy the same stock tubes again and get noisy ones? Is noise more related to tube type or the individual tube you get?

Depending on what kind of noise you mean. Hum, Microphonics etc are all related to the individual tube, usually something loose in the tube itself.

You can also get a hum with a low impedance headphone plugged in since OTL amplifiers are made to work most effective with high impedance.

You could purchase 10 tubes and any of them might hum, be microphonic or just work properly. Certain tube types are more prone to noise than other tubes. A lot of the bigger octals are microphonic for example.

When tubes go bad, they can just cut out on one side or both, they can start to make really nasty noises or distort quite bad, you will know if you have a tube packing in, it happens very quickly.

 

[bbmiller]

You could purchase 10 tubes and any of them might hum, be microphonic or just work properly. Certain tube types are more prone to noise than other tubes. A lot of the bigger octals are microphonic for example.
 

So what do you think of tube vendors that claim they give you tested tubes? And/or balance tubes? Is it worth it to deal with such vendors if the price differential is small? Will such testing eliminate the noisy tubes? Will the tubes become noisy during shipping?

 

[TrollDragon]

  So what do you think of tube vendors that claim they give you tested tubes? And/or balance tubes? Is it worth it to deal with such vendors if the price differential is small? Will such testing eliminate the noisy tubes? Will the tubes become noisy during shipping?

They test tube's for leaks and shorts, they can only test for Microphonics by plugging the tube into an amp and listening to it.
 
Tested tubes are guaranteed to be properly functioning, this all depends on the honesty of the vendor. Balanced / Matched tubes are not required in the LD I+, II, III or IV amplifiers and you are paying for something you don't need.
 
Yes if the tubes are not packed properly and a courier or handler drops the box you can end up with broken tubes, microphonic tubes etc.
 
I haven't had a broken or bad tube from eBay so far but others have, it is the chance you take when purchasing little glass bottles that were manufactured 40+ years ago.

 

[bbmiller]

 Balanced / Matched tubes are not required in the LD I+, II, III or IV amplifiers and you are paying for something you don't need.

This begs the question why? What would be example of a tube amplifier which requires balance tubes and why do the little dot amplifiers you mention don't?

 

[TrollDragon]

  This begs the question why? What would be example of a tube amplifier which requires balance tubes and why do the little dot amplifiers you mention don't?

The Little Dot amplifier's I mentioned do not have phase inverters or a parallel push-pull output, since we don't have to adjust the bias on the tubes, matched pairs are not required.

 

[bbmiller]

 

  This begs the question why? What would be example of a tube amplifier which requires balance tubes and why do the little dot amplifiers you mention don't?

The Little Dot amplifier's I mentioned do not have phase inverters or a parallel push-pull output, since we don't have to adjust the bias on the tubes, matched pairs are not required.

So that infers they are strictly class A. Is that correct? And if that is correct are there any channel balancing inch issues and if so are there any ways to balance the channels?
 
PS I let my own questioning be food for thought to myself. Consequently I have come upon this page "How To Adjust Audio Balance In Windows 7" which will give you a software way of adjusting the balance of an amplifier even if the amplifier is in imbalance because of hardware problems not software interface hardware problems.
 
Perhaps I should amend my above question to do you think by using unmatched tubes and saving money it could be necessary to go through a software balance procedure like the one outlined in the link above due to level in balance caused by using unmatched tubes?
 
I have another question is well. My stock tubes keep improving and improving with increased burning-in. They have now reached the point where on certain files I consider particularly good like the ones of my videos of "John Williams at the BBC proms" which are so good sonically that I have been increasing the volume when listening to them not to give them too much volume overall but to increase the dynamic range. It seems the way my little dot IV amplifier has become with increased burning is that with some very good music video files increasing the volume increases the dynamic range more than what used to happen before my tubes burned in an I would not get increased in dynamic range with increasing volume, but just increase in volume. Have any of you all have experienced the increase in dynamic range with very sonically good files that I am experiencing. If so I will have additional questions.

 

[MIKELAP]

  If you really think the little dot IV se is adequate for those expensive HD 800s and have heard them with other amplifiers that's impressive? I heard the HD 800s are notoriously hard to drive. I myself am waiting for CanJam @ RMAF to hear my first other audiophile grade equipment. I am very impressed with the sound of my little dot IV se which just the stock tubes right now, but will be very interested in seeing if I could hear better sound through my HD 600s with other amps, and what ever, with the same music and singing I am impressed with at home.

While i use the HD 800 with the Littledot i mostly use them on a Woo Audio 2 and a Burson Conductor .Audio shows were a real eye opener for me because for me i found out that at one point its only subtle differences