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Little Dot I+ Tube Rolling - Page 103

post #1531 of 2052

I have to say, the Sylvania Gold Brand 408A is by far my favorite tube to use with the Little Dot 1+, no matter which headphone I use with it.

 

IMHO, soundstage, imaging, detail, and bass quality can't be beat with this tube. 

 

Just sayin'.......

post #1532 of 2052
Quote:
Originally Posted by gibosi View Post

"Gauge" is the standard way to indicate wire thickness.

 

Only on your side of the pond. Most of us have gone metric: http://www.canford.co.uk/Technical/PDFs/EN/MetricAwgWireSizeEquivalents.pdf

post #1533 of 2052
Quote:
Originally Posted by levinhatz View Post

I have to say, the Sylvania Gold Brand 408A is by far my favorite tube to use with the Little Dot 1+, no matter which headphone I use with it.

 

IMHO, soundstage, imaging, detail, and bass quality can't be beat with this tube. 

 

Just sayin'.......

 

If you are comparing these only to the standard EF91, EF92 and EF95 tubes, I would agree with you. The Sylvania 408A with gold pins are indeed superb. However, if you go beyond the standard tubes to include, for example, 6AH6, 6AU6, 6AV6, 6BY6, 6CS6, 6DT6 and 6EB6, there are any number of tubes that far exceed them, IMHO..... :)

post #1534 of 2052
Quote:
Originally Posted by gibosi View Post

 

If you are comparing these only to the standard EF91, EF92 and EF95 tubes, I would agree with you. The Sylvania 408A with gold pins are indeed superb. However, if you go beyond the standard tubes to include, for example, 6AH6, 6AU6, 6AV6, 6BY6, 6CS6, 6DT6 and 6EB6, there are any number of tubes that far exceed them, IMHO..... :)

 

Surprised that those will work with the LD1+ as the manual specifically lists 5654, EF92, and 408A as the "only" tube families that the LD can take. What jumper settings does one use for those tubes? Same ones as EF92?

post #1535 of 2052
Quote:
Originally Posted by levinhatz View Post

 

Surprised that those will work with the LD1+ as the manual specifically lists 5654, EF92, and 408A as the "only" tube families that the LD can take. What jumper settings does one use for those tubes? Same ones as EF92?

 

In the Little Dot tube rolling forum, page 77, you will find a chart indicating how to use these tubes.

 

http://www.head-fi.org/t/563884/little-dot-tube-amps-vacuum-tube-rolling-guide/1140#post_9392055

 

Some tubes are simply "plug and play". And some require small tweaks which are relatively easy to accomplish, either by cutting pins, or inserting a small piece of wire into the socket holes (from the top) in order to connect certain pins together. For example, to use the 6AV6 triode, set your LD up for EF92 and cut off pins 5 and 6. To use the 6AU6 and 6AH6, set your LD up for EF95 and insert a very small piece (28 gauge or smaller) of stranded wire into the socket to connect pin-holes 2 and 7.

 

Cheers

post #1536 of 2052

Great Gibosi !!:bigsmile_face:

 

I've recived today LME49990 opamp, must make more burn in, but i can say that first thing that i noted is  : refined, transparent, clean, treble are very detailed and come outside more ( and what quality !!) then previous opa.

 

Generally, for bass, medium, hight, is one not small step more high than stock opamp.

Part where they improve more ? No doubt, highs !

 

Until now, thanks of the good advice, no one of the tubes and opamp i was wrong.

 

 

 

 

Quote:

Originally Posted by gibosi View Post
 

LME49990 opamp

 

Perhaps like a lot of forum members, shortly after purchasing my LD 1+, I rolled in a OPA2107 opamp, and for sure at the time, I felt it was a significant improvement over stock. Recently however, I have been feeling that this chip is rather dark, as it seems the highs are rolled off to some degree, and I have been searching for other opamps to try. One that stood out was the LME49990. Actually this is a single opamp, so it is necessary to install two of them on a DIP8 adapter. As I am not all that comfortable with a soldering iron, I purchased a pre-assembled unit from this vendor:

 

http://www.ebay.com/itm/DUAL-SOIC-LME49990-DIP8-ADAPTER-/190888281070?pt=US_Amplifier_Parts_Components&hash=item2c71d403ee

 

I rolled it in last night and based on my impressions so far, this chip delivers on all counts. The base has more weight and slam than the OPA2107 and the mids are more neutral. In contrast, the mids on the OPA2107 are a bit more forward, and sometimes vocals almost seem to come across as a bit shouty. And the highs... Extended, clean and clear, with a bit of sparkle. Not rolled off like the OPA2107. So in a nutshell, this is a very neutral and transparent opamp which allows the true nature of the driver tubes to shine through. In fact, some tubes that I had previously thought too forward, are now much easier on my ears and even quite pleasant.

 

In short, I am very pleased with this opamp, but I am not all that surprised. I figured that if these opamps were specifically selected for use in the Parasound Halo CD 1, they just might be good enough for my 1+. lol

 

Recommended

post #1537 of 2052

It's a little of topic but is it true that you need to turn the Little Dot 1+ off and let it cool after some hours use? And if so - why is it necessary? I have used tubes in preamps, cd-players and headamps before and never had any problems whatsoever. Does it get very hot or is it the wattage rating of the resistors?


Best regards,

VB (soon to be Little Dot owner)

post #1538 of 2052
Quote:
Originally Posted by VBen View Post
 

It's a little of topic but is it true that you need to turn the Little Dot 1+ off and let it cool after some hours use? And if so - why is it necessary? I have used tubes in preamps, cd-players and headamps before and never had any problems whatsoever. Does it get very hot or is it the wattage rating of the resistors?


Best regards,

VB (soon to be Little Dot owner)

 

David Zhe Zhe says that it should be switched off to cool after eight hours of use, though I am not sure why.

post #1539 of 2052

There have been a few reports of some heat damage and resistors failing near some of the actives that get very hot when the amp was used for extended sessions.  I'd say using the 8 hour rule of thumb for a cool down is likely good practice for this amp.  

post #1540 of 2052
Quote:
Originally Posted by shipsupt View Post
 

There have been a few reports of some heat damage and resistors failing near some of the actives that get very hot when the amp was used for extended sessions.  I'd say using the 8 hour rule of thumb for a cool down is likely good practice for this amp.

 

Ok, thank you for the answer. When I get it I probably try to check where it gets hot. Maybe some parts can be changed or given better cooling. I don't like to turn off preamps and such (its probably all those years using Black Gate capacitors).

 

 I'm really looking forward to getting the Little Dot though. My Musical Fidelity X-Can V2 "kicked the bucket" last week, and I'm hoping that the 1+ can surpass it. Soundwise at least.

post #1541 of 2052

Just received the Little Dot 1+ this week, but alas one of the tubes was a dud. Luckily enough I had bought a pair of Voskods just in case. The amp sounds very good already but how long does it take to burn it fully in, and what kind of changes can I expect?

 

Regards, VB

post #1542 of 2052
Quote:
Originally Posted by VBen View Post
 

Just received the Little Dot 1+ this week, but alas one of the tubes was a dud. Luckily enough I had bought a pair of Voskods just in case. The amp sounds very good already but how long does it take to burn it fully in, and what kind of changes can I expect?

 

Regards, VB

 

Tubes generally take anywhere from 20 to 50 hours to burn-in. With respect to the entire amp, I would guess that 50 to 100 hours for a brand-new amp is not an unreasonable. That said, I suggest that you not worry about this, but just listen and enjoy. :)

post #1543 of 2052

Sound advice indeed! The bass is very very strong at the moment and the soundstage is a bit "underdeveloped". I'll guess that some burn-in will do the trick....Or another set of tubes.

post #1544 of 2052

Asking how long a tube takes to burn-in is like asking how long a light bulb takes to burn in, and how many problems has anyone had with that? ;)

post #1545 of 2052
Quote:
Originally Posted by Tus-Chan View Post
 

Asking how long a tube takes to burn-in is like asking how long a light bulb takes to burn in, and how many problems has anyone had with that? ;)

 

It isn't really a problem. However, the sonic signature of a tube will often change during burn-in. Sometimes these changes are very subtle but sometimes they can be quite dramatic. Therefore, it is best to thoroughly burn your tubes in before making a final evaluation.

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