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Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 274

post #4096 of 10500

Similar to AFB's 1962 US-Amperex 6922, in my camp, the 1961 holds the throne. However, today I received what I expect to be some major contenders to that throne.

 

Recently, in the Lyr tube thread, I read a review by rb2013 comparing three 1975 Voskhods and a 1965 US-Amperex 7308.

 

http://www.head-fi.org/t/673709/schiit-lyr-tube-rollers/750#post_9997718

 

I already had some 1975 Voskhods on the way and then stumbled on a couple US-made Amperex 7308s, 1965 and 1966, and decided to get them. They were $30 each, way beyond $8, but figured it was highly unlikely I would ever find these for anywhere close to $8....

 

So anyway, I now have two of the three Voskhods and the 1965 7308 used in that review, so figure I am about ready to have a similar tube "faceoff" between these contenders and my 1961 6922. I have checked to see that these newcomers light up and play, and while I am not sure they need to be burned in, figure it still might be a good idea.....

 

First the Voskhods: rb2013's tied for second and third place winners

 

Evidently, there are four different versions of the 1975 Voskhod, based on shield color and getter post. The two I received today have gray shields, but the left one has a wire getter post and the other has a post that appears to be an extension of the shield.

 

 

And the US-Amperex 7308s: rb2013's tied for second place winner

 

Even though manufactured almost exactly a year apart (65-42 and 66-40), both have the same change code, and thus I expect them to be virtually identical.

 

post #4097 of 10500

Ive been listening for quite a while to the 6BQ7A WESTINGHOUSE tubes that have around 40 hours on them so today decided to put back on a pair of G.E.6DT6A and my first impressions  is that they sounds lean compared to the warm cosy sounding 6BQ7A but after a few minutes you get use to the more detailed neutral sounding 6DT6A that have about 30 hours on them and thats with the Senns HD 800 by the way . 

post #4098 of 10500

I was just wondering what everyone has their "Gain" set to?

 

When I received the MK IV it came factory at 3, this setting sounded horrible so I moved it to 5, the sound was much better and that is where it has stayed since.

With all these tube sound impressions, I was just wondering what you all use since the gain setting does affect sound.

post #4099 of 10500
Hey MIKELAP!

I just popped in the exact same 6DT6A's, these ones seem to have a little hum when unstrapped so I am trying 2-7 right now. Is that how you run yours?
post #4100 of 10500
Quote:
Originally Posted by TrollDragon View Post

Hey MIKELAP!

I just popped in the exact same 6DT6A's, these ones seem to have a little hum when unstrapped so I am trying 2-7 right now. Is that how you run yours?

No i did not strap them yet. And by the way gain is on ten.

post #4101 of 10500
Quote:
Originally Posted by MIKELAP View Post
 

No i did not strap them yet. And by the way gain is on ten.


Excellent Thanks!

post #4102 of 10500
Quote:
Originally Posted by TrollDragon View Post
 

I was just wondering what everyone has their "Gain" set to?

 

When I received the MK IV it came factory at 3, this setting sounded horrible so I moved it to 5, the sound was much better and that is where it has stayed since.

With all these tube sound impressions, I was just wondering what you all use since the gain setting does affect sound.

 

I have heard that it is best to set the gain setting as low as possible, that the lower the resistance in the sound path the better. But I must confess that I do not understand the whys and wherefores....

post #4103 of 10500

Just running my Tragically Hip select cuts through the 6DT6A's

 

Blow At High Dough
Little Bones
Twist My Arm
At The Hundredth Meridian
New Orleans Is Sinking
38 Years Old
Boots Or Hearts
Fully Completely
Fifty-Mission Cap

 

:beerchug:

post #4104 of 10500
Quote:
Originally Posted by gibosi View Post
 

 

I have heard that it is best to set the gain setting as low as possible, that the lower the resistance in the sound path the better. But I must confess that I do not understand the whys and wherefores....


I don't either but the lowest gain on my amp didn't sound very good.

post #4105 of 10500
Quote:
Originally Posted by TrollDragon View Post
 

I don't either but the lowest gain on my amp didn't sound very good.

 

I have also heard that setting the volume control between 10 and 2 is optimal. If so, then perhaps setting the gain such that your preferred listening level is achieved with the volume between 10 and 2 makes some sense? (Again, I am just stabbing in the dark, as usual! lol :)

post #4106 of 10500
Quote:
Originally Posted by gibosi View Post
 

 

I have also heard that setting the volume control between 10 and 2 is optimal. If so, then perhaps setting the gain such that your preferred listening level is achieved with the volume between 10 and 2 makes some sense? (Again, I am just stabbing in the dark, as usual! lol :)


Yes I have my volume at 11 right now with a gain of 5. It seems to work nicely keeping the volume control close to middle so there is plenty of play either way. :D


Edited by TrollDragon - 11/28/13 at 9:00pm
post #4107 of 10500

Left the gain on the factory setting - don't remember what it is. As for volume on the MKIII, I turn it up until I hear distortion, and then back off a little. My volume control has a scale etched on the face plate, and I usually set it to around 80, which would correspond to around 3 o'clock. This is for listening through speakers.

 

Using headphones this is way too loud, and my regular setting is around 20 on the face plate corresponding to 9 o'clock.

 

When using speakers I found the bass to get better at close to clipping on the LD. Using the above setting for speakers the volume is controlled by my receiver which is set quite low since the LD amplifies the signal to play louder than using the receiver alone.

 

Having the receiver volume fairly low I cannot hear hum, but when I turn up the receiver volume to very loud there is a faint hum. This us usually drowned out by the music, but if I don't play anything and turn the volume very high I hear hum.

post #4108 of 10500
Quote:
Originally Posted by TrollDragon View Post

I was just wondering what everyone has their "Gain" set to?

When I received the MK IV it came factory at 3, this setting sounded horrible so I moved it to 5, the sound was much better and that is where it has stayed since.
With all these tube sound impressions, I was just wondering what you all use since the gain setting does affect sound.

I played a lot with different gain settings when i got my amp. Gain 4x was the best for me every time.

Diy tube headphone amp project have been eating my sparetime really badly. Hope to get 6A6 tubes in good use with first prototype. They were not so good for little dot.

I got my first 4 pairs of real 6SN7 tubes yesterday. One was dud,but thankfully it was the least interesting pair. Hope i could say something about sound affects of these tubes one day. Since no one else is not using these as powertubes yet,there is no hurry to give any ratings for these.

Bought Philips SHP895 headphones for 10 euros and have been using them. Sound is much calmer and smoother with these than superluxes. I could even listen some heavier music. It takes time to get used to new sound.
post #4109 of 10500
Thanks mordy and Artsi!

mordy you should try a different gain setting 4 or 5, you might be pleased with the results.

Artsi are you building a DIY amp? If so check into the "I (Heart) Tube Amps" group on Facebook, those guys there really know their stuff.
post #4110 of 10500

Here is a link to MKIII/IV gain settings from the Little Dot forum:

 

http://www.littledot.net/forum/viewtopic.php?t=422

 

Seems that Texas Instruments agrees with my approach of high volume from the LD into the power amp and power amp on very low. (If I understand this correctly)

 

 

"Gain Setting for the Audio Power Amplifier
It is also imperative to understand that the output signal from the CODEC or DAC driving the
audio power amplifier should be as large as possible, to have a high SNR. Conversely, the gain
of the audio power amplifier is set as low as possible. If the audio power amplifier’s gain is set
too high, then it amplifies the noise floor, along with the actual wanted signal of the CODEC or
DAC. This decreases the dynamic range of the signal and reduces the quality of the sound."

 

 

Posts: 4

Joined: Feb 22nd, '09, 06:18


Edited by mordy - 11/29/13 at 9:08am
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