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Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 79

post #1171 of 6976
Quote:
Originally Posted by john57 View Post

On some of the LD products you make to make sure that you have enough room to insert the socket saver because of the rings.

 

Perhaps this picture will help people determine if it will fit in their LD....

 

post #1172 of 6976

well, that was disappointing. I did the wire mod like you have shown in the diagram, the settings on the amp are for standard ef95 tubes, once i turned the amp on i could hear a kind of crackling sound, just once from each headphone, when i put them on, immediately there were microphonics, the slightest touch anywhere near the amp was picked up, the open mic effect.  didn't really get passed that to be honest. the good news though, I did win the bid on the sylvania gold brands, bloody expensive but so rare now there cant be many more of them out there. 

post #1173 of 6976
Quote:
Originally Posted by vic2vic View Post

$50-$60 for delivery cost :-(

 

I am very surprised! :(

 

Probably because most US vendors prefer to use Express mail because it provides for tracking which makes it easier to resolve shipping problems. But I had no idea international Express mail was this expensive.... :(

 

Leeds Radio has been in business since 1923 and specializes in vintage electrical parts manufactured before 1968.

 

http://www.nytimes.com/2011/11/20/nyregion/leeds-radio-is-a-haven-for-lovers-of-all-things-analog.html?_r=0

 

There must be similar places in Europe.... Good luck!

post #1174 of 6976
Quote:
Originally Posted by zedmeco View Post

well, that was disappointing. I did the wire mod like you have shown in the diagram, the settings on the amp are for standard ef95 tubes, once i turned the amp on i could hear a kind of crackling sound, just once from each headphone, when i put them on, immediately there were microphonics, the slightest touch anywhere near the amp was picked up, the open mic effect.  didn't really get passed that to be honest. the good news though, I did win the bid on the sylvania gold brands, bloody expensive but so rare now there cant be many more of them out there. 

 

The crackling sound likely indicates that the connection is poor. And with poor connections I have had tubes go microphonic that normally have no microphonics. You used a small piece of stranded wire in the socket?  Are you sure you have pins 2 and 7 connected? Since the sockets are a mirror image of the tube, it is easy to make a mistake. I would recommend you double check everything and try again.


Edited by gibosi - 5/3/13 at 6:31am
post #1175 of 6976

hi, i used 5amp fuse wire, wrapped it about three times around pin 2 keeping back about a centimetre over hang, then onto pin 7, three wraps around that and then back to pin 2, two more wraps and then i twisted together the the two ends of the wire, a couple more wraps around pin 2, and then cut off the excess. do you think there would be a bad connection? i am keen to hear these tubes but my fear of damage to my amp is back. 

 

just tried it again, i scraped the bottom of the pins, and then used a slightly thicker piece of fuse wire, same result. never mind, i must just have two dud tubes.


Edited by zedmeco - 5/3/13 at 8:20am
post #1176 of 6976
Quote:
Originally Posted by zedmeco View Post

hi, i used 5amp fuse wire, wrapped it about three times around pin 2 keeping back about a centimetre over hang, then onto pin 7, three wraps around that and then back to pin 2, two more wraps and then i twisted together the the two ends of the wire, a couple more wraps around pin 2, and then cut off the excess. do you think there would be a bad connection? i am keen to hear these tubes but my fear of damage to my amp is back. 

From your description, it sounds to me like there is way too much wire wrapped around the pins. When you attempt to insert the tube, all this wire is very likely preventing the tube from seating properly into the socket and preventing the pins from making a good connection, especially pins 2 and 7. Click on the picture I posted above with 30 gauge wire. Notice that I have only one wrap on both pins and I am using a very small wire.... In this way, even though I used no solder, the tube seated properly, the pins were inserted deeply and the resulting connections were very good.

 

Again, please trust me on this...  To begin, get some 26 gauge or smaller stranded wire and drop one end into the hole for pin 2 and the other into the hole for pin 7. And then, if you really like them, you can take the time to research and experiment to figure out how to mod the tube with a soldered wire. Cheers.

post #1177 of 6976

Hi Z,

 

I was also apprehensive about the wire strap mod, but it is really very simple. I am sure that you have a set of earphones or iPod wire somewhere that don't work. Cut off the wire, take a scissors or a little knife and peel back all the braiding and other stuff, and you should have a couple of very thin insulated stranded wires in there.

Cut off an little piece (an inch or 2-3 cm). Then remove the colored plastic sheath from the wire with your nails or a wire cutter  or pliers, stripping one end about the length of one of the pins on the tube. Bend the wire 90 degrees, put it in the socket (make sure amp is off) and mark off where you should strip the other end of the wire. Cut off the excess wire, and strip the other end. Bend the wire 90 degrees. What you have now should look like a staple with two bare ends and insulation in the middle. Twist together the bare wire ends with you fingers. Then drop into socket holes 2&7 with a tweezers or small pliers. You may need to push a little with a tool or with your fingers to get the wire strap into the right place.(Again, make sure that you have the right location of the holes.)

Take the tube and push in gently, watching that the wire stays in the holes. If there is crackling or no sound, move the tube around a little to make better contact.

So far we have not heard of any damage to the amp by trying these mods, even when mistakes were made.

post #1178 of 6976
Quote:
Originally Posted by zedmeco View Post

hi, i used 5amp fuse wire, wrapped it about three times around pin 2 keeping back about a centimetre over hang, then onto pin 7, three wraps around that and then back to pin 2, two more wraps and then i twisted together the the two ends of the wire, a couple more wraps around pin 2, and then cut off the excess. do you think there would be a bad connection? i am keen to hear these tubes but my fear of damage to my amp is back. 

 

just tried it again, i scraped the bottom of the pins, and then used a slightly thicker piece of fuse wire, same result. never mind, i must just have two dud tubes.

 

Hi there z,

 

You must be feeling rather frustrated/disappointed by now but may I add my support for mordy's advice re using the wire mod in the sockets. Read all the info on this via the many posts - there is also a diagram by audiofanboy on page 59 - and be sure to connect the correct holes in the socket and use thin stranded wire. It really is the easiest way to begin with.

 

You would have to be really unlucky for both tubes to be dud, but there is always the slightest possibility that could be the case, viz a couple of posts methinks have mentioned faulty 6485s and 1 of the first 3 (of ten) I have tried from the same source proved dud...

 

So please persevere - the sound that comes from these tubes is AMAZING and well worth a bit of a struggle.

 

Good luck

post #1179 of 6976

Hi Z,

 

Socket wire mod ftw! Don't worry about the socket if you are using fine stranded wire. I have used an old wire from a an old internal PC connector, with 3 strands, black, red, yellow, kind of like the fan wires. The only disadvantage is that you need to fix it occasionally after pulling out the tube. I would also recommend to make a shorter jumper in order to connect pins 6 and 7 on the socket for the EF91/92 setting. This way, you never ever need to worry about which setting your LD jumper is set to (which is the EF95 setting). Just do it :)

 

Burning in at the moment a fresh Tung Sol 6BE6 tube. Sounds good so far :)

 

Recently, I had a few changes in my gear, so I have to get used to the sound. I have to go back to reference tubes in order to reorient myself plus I am comparing old and new gear. Interesting for me, not perfect to compare tubes, but I am on it.

post #1180 of 6976

About faulty tubes:

 

Before writing off the tube (unless the silver inside turned to WHITE, which means that the tube is really dead - vacuum lost), you must try this:

 

Take a little pocket knife or anything similar with a small blade (does not have to be sharp), and carefully scrape the pins gently until they become more shiny.

 

Recently I had a TS tube suddenly stop working. The pins did not look corroded, just a little burnished. Tried the tube in another socket, moved it around in the socket - nothing helped. Then  I remembered the scraping trick. The tube came back to life and has functioned fine since then.

 

 

This has helped for crackling tubes as well.
 

post #1181 of 6976

thanks for all the advice everyone, this morning i was compelled to try again, i scraped all the pins, got some fresh wire from an old mini jack to phono lead, stripped a 2 inch section of it to bare wire strands, took about half of the strands and twisted them together making a very thin piece of wire. i then connected pins 2 and 7 together taking care only to make one twist around each pin and then cutting off the excess wire right up to the pin. the connection is almost flush to the glass, maybe less then a millimetre up the pin. i pressed them home into the socket, giving a little jiggle as they went in and seated tight. headphones on, no crackle! result, still microphonic but less so, probably a result of the scraping! got a track on and listening now, great separation of all the sounds, really nice sound stage. seems a flat response to me, no spurious frequency enhancement, a good thing as i use the set up for music production. but then half way through, i could hear a high frequency, almost like a chime in the back ground. this lead to the crackle which started to get louder, at which point i switched the amp off. these are clearly superior tube, but i seem to be unable to get a good connection and the amp got a lot hotter a lot quicker too, less then 5 minutes and the whole amp was hot.  

 

i love my amp, champagne audio for lemonade money. i listen/write music all the time, i can put in 8 hour stretches and the sound is not fatiguing in any way, my butt gets tried before my ears! i will keep following this wonderful thread but i don't think i am going to try them again. thanks once again z

post #1182 of 6976
Quote:
Originally Posted by zedmeco View Post

thanks for all the advice everyone, this morning i was compelled to try again, i scraped all the pins, got some fresh wire from an old mini jack to phono lead, stripped a 2 inch section of it to bare wire strands, took about half of the strands and twisted them together making a very thin piece of wire. i then connected pins 2 and 7 together taking care only to make one twist around each pin and then cutting off the excess wire right up to the pin. the connection is almost flush to the glass, maybe less then a millimetre up the pin. i pressed them home into the socket, giving a little jiggle as they went in and seated tight. headphones on, no crackle! result, still microphonic but less so, probably a result of the scraping! got a track on and listening now, great separation of all the sounds, really nice sound stage. seems a flat response to me, no spurious frequency enhancement, a good thing as i use the set up for music production. but then half way through, i could hear a high frequency, almost like a chime in the back ground. this lead to the crackle which started to get louder, at which point i switched the amp off. these are clearly superior tube, but i seem to be unable to get a good connection and the amp got a lot hotter a lot quicker too, less then 5 minutes and the whole amp was hot.  

 

i love my amp, champagne audio for lemonade money. i listen/write music all the time, i can put in 8 hour stretches and the sound is not fatiguing in any way, my butt gets tried before my ears! i will keep following this wonderful thread but i don't think i am going to try them again. thanks once again z

 

A couple things come to mind. First, the wire connecting pins 2 and 7 had no insulation? If so, bare wire may well have been in contact with the metal surrounding the socket center hole, and this is likely not good. And two, when I wrapped solid core wire around the pins, I could count on it to stay in place. Stranded wire wrapped around the pins can easily come unraveled. Thus, I am guessing you did not have a good connection.....

 

With all due respect, you still have not tried the one solution that all of us have suggested, that is, putting a small piece of stranded wire into socket pin holes 2 and 7. If you do this (but you need to leave some insulation on the wire where it could come in contact with the metal surrounding the socket center hole), you will most certainly have a good electrical connection. And then you can finally relax and check out these tubes.  And then, if you decide you really like them, solder a similar piece of wire onto the pins and you won't ever have to worry about this again...  

 

Oh, are your Sylvania gold brands 6AU6 by chance?

post #1183 of 6976

hi, i did try the wire in the socket mod last night, i couldn't find any wire thin enough so i used a bit of electrical tape over the centre of the socket, i think i am going to hunt something really thin and get the soldering iron out! they did sound nice i must confess.

i just won the bid and still waiting for the Sylvania Gold GB 5654 6AK5 EF95 JAN, these are supposed to be very special, i will let you know. wish me luck, i am going i am for the soldering iron!

post #1184 of 6976

i found some old computer interconnect, the long thin ribbon type, cut off one little wire, cut it to size, stripped away the insulation at the ends, put a bit of solder around the wire ends, the insulation fit exactly between the pins, i bent the wire so it just cupped the pin, applied the solder, a firm connection, put the tubes into the socket, no crackle but still the microphonics. i had a listen to this,  http://youtu.be/qt9p9ZqI-yI which as a piece of music is fantastically produced. the tubes sounded fab, there is no denying it, but half way through, the crackling started again, i moved the tube in the socket to the accompaniment of some very unhappy sounds. i whipped them out, cut a fresh pair of this very thin wire, put the ends into the sockets, carefully inserted the tube, same story as before. no crackle again but still terrible microphonics. the crackle came back in after about 3 minutes, during which time, everything got very hot. i think they do work and they do sound good, but i don't think the amp is too happy with them, the tolerances are not the same. i stuck the voskhod back in, i must tell you, this is a good sound. fantastic sound stage, deep, controlled bass, amazing detail in the mid and hi ranges, and i don't have the feeling the amp is going to blow! i think the beautiful thing about the amp is we have the ability to customise the sound with our tube selections, and there are many different flavours to sample, but we all have a different requirement, i need the sound to be flat with no coloration, so my mixes will sound good on other peoples equipment, with everything in balance, if a tube gives more bass, then when i am mixing, i will add less bass, and when you listen to it, it will be light in the bass. anyhow, thanks once again, for now, i am going to stick with the ef95's. z

post #1185 of 6976

Hi,zedmeco do you have music on sound cloud possibly electronic, i remember that icon from somewhere !


Edited by MIKELAP - 5/4/13 at 5:41pm
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