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Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 261

post #3901 of 10566

I put in the Sylvania 6AQ6 tubes and heard loud humming noise as I was playing my music. I have it on EF92 mode and I cut off pins 5 and 6 as well. I'll show you guys pics in a couple of minutes....

 

What could it be?

Warning: Spoiler! (Click to show)
Stupidity?
post #3902 of 10566
Quote:
Originally Posted by Sony Slave View Post
 

I put in the Sylvania 6AQ6 tubes and heard loud humming noise as I was playing my music. I have it on EF92 mode and I cut off pins 5 and 6 as well. I'll show you guys pics in a couple of minutes....

 

 

It is not uncommon for tubes to buzz and hum when they are new. Typically, after 10 to 20 hours of use they quiet down. If they do not improve, you may want to consider requesting new tubes or money back from the vendor.

post #3903 of 10566
Quote:
Originally Posted by gibosi View Post
 

 

It is not uncommon for tubes to buzz and hum when they are new. Typically, after 10 to 20 hours of use they quiet down. If they do not improve, you may want to consider requesting new tubes or money back from the vendor.

Oh ok.

 

Here's a pic of cut off pins of the tube and circuit board of the little dot,

 

 

It seems that the Little Dot 1+ is set up to EF92 correctly.

Pins are cut off as well.

 

I'll keep playing music with them to see if they go away over a couple of days.


Edited by Sony Slave - 11/10/13 at 12:15pm
post #3904 of 10566
Quote:
Originally Posted by Sony Slave View Post
 

Oh ok.

 

Here's a pic of cut off pins of the tube and circuit board of the little dot,

 

this is the pins you cut off arrows

 did you put electrical tape over pins you cut off

 


Edited by MIKELAP - 11/10/13 at 12:17pm
post #3905 of 10566
Quote:
Originally Posted by MIKELAP View Post
 

this is the pins you cut off arrows

 did you put electrical tape over pins you cut off

 

No, I did not 

 

I'm gonna go to my local radio shack and see if they have some electrical tape. 

post #3906 of 10566
Those pins do not look too flush, try putting the tube back in and do not put it down all the way. To make sure those pins do not touch the socket and see if the hum goes away. A loud hum that is not controlled by the volume control is a problem.
post #3907 of 10566
Quote:
Originally Posted by Sony Slave View Post
 

No, I did not 

 

I'm gonna go to my local radio shack and see if they have some electrical tape. 

You could file down the pins if you have a small file a dremel is not recommended vibration could crack the tube it happened to me 

post #3908 of 10566

Hi Artsi,

 

Would like to try some octal driver tubes. What do you think of this? ($2/tube + shipping  = $12.24 for two by snail mail)

 

http://rutubes.com/product/6n9s-6sl7-6su7-ecc35-tube/

 

or this one : $9 shipped

 

http://www.ebay.com/itm/VINTAGE-SOVIET-USSR-PENTODE-VACUUM-TUBE-triode-pentode-6N9S-6-9-NOS-/121210957735?pt=Vintage_Electronics_R2&hash=item1c38bc6fa7

 

There are 60's tubes available as well: ($13.38 for 2 tubes incl shipping)

 

http://www.ebay.com/itm/VINTAGE-SOVIET-USSR-PENTODE-VACUUM-TUBE-triode-pentode-6N9S-6-9-NOS-/121210957735?pt=Vintage_Electronics_R2&hash=item1c38bc6fa7

 

How about $17.90 for four 1970's tubes shipped?

 

http://www.ebay.com/itm/4-x-6SL7-6N9S-1579-tubes-Reflector-NEW-NOS-1970s-/161080111697?pt=Vintage_Electronics_R2&hash=item25811f7251

 

It is difficult for me to find information what are the best brands and best years of inexpensive 6N9S tubes. There is no difficulty to find the most expensive ones...

 

If you have a link to a site evaluating these tubes, please post it.

post #3909 of 10566

The Dremel cutoff disk does an amazing job flush cutting the pins off of the 6AV6.

Unless you pull a Deluxe bone head move like I did and forget how to count... :rolleyes:

 

Luckily I was able to jury rig a pin from twisted Cat 5 cable and butt solder it back in place. The glass of the NEC 6AV6 was a lot stronger than the glass in the 6Ж5П I tried to solder the permanent 2-7 strap to, which cracked as soon as the heat was applied.

 

The pseudo pin is solid and the tube still works but the treble is so harsh on it that I will never play these tubes...

But they do look pretty when all lit up. :D

post #3910 of 10566

Hi Gibosi,

 

Playing my 1975 Amperex A frame 6DJ8. In comparison to my Sylvania 12AX7A they are more detailed, etched, with stronger bass and punch in treble, but the Sylvania is more musical and sweet, but with less detail. Both tubes are very enjoyable and the jury is still out what I prefer.

 

What is not enjoyable is that the wires on my spider web adapter break all the time when I move the adapter. They break at the soldering points at the Vector adapter.

 

What kind of wire is the thickest and most flexible that can be used with the Vector adapter (fitting through the little holes on the tabs) without soldering and just using the pressure of the tabs? Presently I use solid 22 gauge wire. Would stranded wire be better?

 

On my 6DJA adapter I use a breadboard with 30 gauge wirewrap solid wire without soldering. This seems to work better, but it seems to me that the wire is too thin to resist breakage (which already happened).

 

Any advice?

post #3911 of 10566

I had the tubes barely get inside the sockets and they were still humming.

It wasn't noticeable when music was playing, unless there was a quite passage.

 

It reminded me of the Tung-Sols that I purchased a while back, they had a quieter hum that these Sylvanias and it had distortion as well, but it made it up for adding a touch of warmth to my cans.

 

I'm guessing it's the tube itself correct?

 

I'll guy buy a smile file along with the electrical tape. It that doesn't solve the problem, i'll keep using them to see if they improve.


Edited by Sony Slave - 11/10/13 at 1:28pm
post #3912 of 10566
Quote:
Originally Posted by mordy View Post
 

Hi Artsi,

 

Would like to try some octal driver tubes. 

 

I bought mine from here http://www.ebay.co.uk/itm/271295938589. Packets come much quicker from Bulgaria than from Russia. People say that old ones with metal base are better, but i can't say anything about that. Parts inside tubes look similar to me from 50's to 80's with "plastic" base.

http://www.ebay.co.uk/itm/6SL7-RARE-VINTAGE-6N9S-1579-2-NEW-NOS-1959-/161044298382

http://www.ebay.co.uk/itm/USSR-6N9S-1579-6SL7-tube-Double-triode-NOS-QTY-4-/251240604156

 

Older metal base version seem to have shinier plates. So there could be difference in sound.

http://www.ebay.co.uk/itm/6N9S-6H9C-6SL7-1579-Vintage-Year-1954-Metal-Base-Black-Plate-MELZ-Strong-Tube-/141102357107

post #3913 of 10566
@mordy Get some 22 AWG stranded wire for you hook ups, clean off the terminals of the vector sockets with some sand paper or a file till the brass shows then solder with a high heat gun till the solder melds with the brass. Then tin and solder your 22 AWG stranded to the terminals. They won't break again if soldered properly this way I guarantee it!

Use the 22 AWG on your tube bread board as well.
beerchug.gif
Edited by TrollDragon - 11/10/13 at 1:17pm
post #3914 of 10566
Quote:
Originally Posted by mordy View Post
 

Hi Artsi,

 

Would like to try some octal driver tubes. What do you think of this? ($2/tube + shipping  = $12.24 for two by snail mail)

 

http://rutubes.com/product/6n9s-6sl7-6su7-ecc35-tube/

 

or this one : $9 shipped

 

http://www.ebay.com/itm/VINTAGE-SOVIET-USSR-PENTODE-VACUUM-TUBE-triode-pentode-6N9S-6-9-NOS-/121210957735?pt=Vintage_Electronics_R2&hash=item1c38bc6fa7

 

There are 60's tubes available as well: ($13.38 for 2 tubes incl shipping)

 

http://www.ebay.com/itm/VINTAGE-SOVIET-USSR-PENTODE-VACUUM-TUBE-triode-pentode-6N9S-6-9-NOS-/121210957735?pt=Vintage_Electronics_R2&hash=item1c38bc6fa7

 

How about $17.90 for four 1970's tubes shipped?

 

http://www.ebay.com/itm/4-x-6SL7-6N9S-1579-tubes-Reflector-NEW-NOS-1970s-/161080111697?pt=Vintage_Electronics_R2&hash=item25811f7251

 

It is difficult for me to find information what are the best brands and best years of inexpensive 6N9S tubes. There is no difficulty to find the most expensive ones...

 

If you have a link to a site evaluating these tubes, please post it.

http://www.head-fi.org/t/353051/best-sounding-6sl7-short-glass-version-tubes-advice-need-it-pls     Skylab speaks of favorite 6SL7 tubes

post #3915 of 10566

I covered the exposed pins on the Sylvanias with electrical tape, and I still hear the humming. I didn't file down the metal yet, so I placed an order for some 10pc small metal files to be shipped in tomorrow.  


Edited by Sony Slave - 11/10/13 at 1:58pm
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