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Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 308

post #4606 of 10501

About the octal adapter im working on would it help the humming issues you think by soldering a small pipe on the exteriour of the adapter and having the 2 heater wires pass thru that pipe and soldered  to there respective pins and would the wires need to be insulated you think or just the fact that they are not next to the other wires be ok except where they go back in the main chassis.Heres a picture .                                                                                                                                                                                                                                                                                                                                               

post #4607 of 10501
Quote:
Originally Posted by Audiofanboy View Post

 

The second you play a track with the PW, you don't even need to close your eyes to feel that you're in a enclosed space with realistic reflections (a sense of true "wetness" to the sound) and liquid tame instrument and voices playing. There's no real 3D or holographic effect anymore, just a studio in front of or in between your eyes, like you're in a smoky club after five drinks or in a studio after working 20 hours without a break, just staring at the musicians in a daze and letting the music "sink in" because you're too tired to tap your feet and really listen at this point. Well that's what the PW are like, and it can make you feel uncomfortable when you're expecting a punchy and forward headphone music session.

 

 

Of course, it is terribly difficult to put into words what we hear...  But I think I could use these same words to describe the 6SN7: There is a strong sense of being in "an enclosed space with realistic reflections (a sense of true "wetness" to the sound)" and very liquid.  After having been totally blown away with the premium 6DJ8, it has taken me awhile to wrap my head around these octals, but I am now beginning to think that I prefer the 6SN7 over the 6DJ8....  And perhaps a Darkvoice 336 over a Lyr.....  

post #4608 of 10501
Quote:
Originally Posted by MIKELAP View Post
 

About the octal adapter im working on would it help the humming issues you think by soldering a small pipe on the exteriour of the adapter and having the 2 heater wires pass thru that pipe and soldered  to there respective pins and would the wires need to be insulated you think or just the fact that they are not next to the other wires be ok except where they go back in the main chassis.Heres a picture .                                                                                                                                                                                                                                                                                                                                               

Liking the Hammertone finish but I think that would be too much work.

 

Unless you ran one on each side like twin feed pipes on an intake manifold... Yeah I'ma be liking that Idea!

 

Just Kidding...

Try a shielded wire to the heater filaments first.

:beerchug: 


Edited by TrollDragon - 1/5/14 at 11:35am
post #4609 of 10501

Don't know if this helps, but in regard to a bread board adapter I found that little thicker wires helped against the hum, and that moving around the bread board in different directions, as well as up or down, would enable me to find a position with less hum. (Obviously this does not work with a stationary adapter plugged into the amp). In addition, moving around the individual wires would also reduce the hum.

 

However, when turning the volume up to a considerably higher level than I normally listen to, there is always a hum. Sometimes I need this high level with a low gain recording, and you notice the hum on soft passages. Looking forward to get my voltage regulator that may get rid of the hum.

post #4610 of 10501

I had a few small packages arrive today:

 

An RCA 6FW8

 

Back in the day, RCA decided not to manufacture the 6DJ8. Instead, they developed and manufactured their own tube to compete directly with the 6DJ8. However, it sold poorly, and in the end, RCA purchased the 6DJ8 from other manufacturers and rebranded it as their own. Anyway, there is not much information about this tube in audio circuits, so I decided to give one a try.

 

 

A 1952 CBS/Hytron 6SN7, rebranded as a Motorola (CBS/Hytron's EIA code is 210). From what I have read, the CBS tube is an excellent tube and often quite cheap. And as this one carried a Motorlola label, I got it for only $7.74 shipped.

 

 

And finally a couple of Loktals, a 7N7 and 7AF7. The 7N7 is electrically identical to the 6SN7. And the 7AF7 is electrically identical to the 6AH7. The 6AH7 is the octal predecessor of the 12AU7, and in a sense, it would seem to be a 300ma version of a 6SN7. These were dirt cheap, $2.00 a tube, shipped. However, I am still waiting for an adapter.....

 

post #4611 of 10501

At last someone has found the great loctals. You will enjoy both of these. Fine tubes at cheap prices. The 7N7 is plentiful and a fine performer. The 7AF7 is much rarer.... If you enjoy these try the 6F8G or the BL63s (not loctals but top caps of similar era) ;) For the latter you will need a good budget and a PSU also.


Edited by Nic Rhodes - 1/6/14 at 11:02am
post #4612 of 10501

I like how the heater on the 6BQ7A runs across the bottom of the tube.

:beerchug:

post #4613 of 10501

Today I got a Crosley 6SL7 made by Sylvania. It was advertised as a Westinghouse made by Sylvania from 1943. I don't think that the box below matches this tube:

                                                                                                                                           

 

 

I assume that the blue stamp was added to correct the misspelling of the word "Contracror" at the end of the Westinghouse line. Here is the tube:

 

On the glass is etched 6SL7GT and below, the letters EOM. The base has the number 312 which is the EIA code for Sylvania and the number 039.

EOM? Maybe May 1950/60? 039? Sept 1950/60? Don't know - but what matters is that this tube sounds excellent. Really good.

 

What about Crosley? Wel,l did you know that Crosley was the largest US manufacturer of radios in the later part of the 1920's? They made refrigerators, cars, TVs etc etc. However, what matters most to us here on the Little Dot forum is that Crosley as early as1925 served as the inspiration of the styling of the LD amp .

 

http://www.99main.com/~allens/pup1.jpg

 

 

http://www.radiolaguy.com/images/flatwork/CrosleyPupS.jpg

 

The Crosley Pup radio cost $9.75 in 1925 = $130 today. Here is a happy early Head Fi-er.

 

http://www.sparkmuseum.com/images/Battery-sets/Crosley-pup-with-Bonzo.jpg

 

 

Here is something for you sports fans out there:1925 CINCINNATI REDS SHARE HEADPHONES AND CROSLEY PUP RADIO MASCOT  (Don't know if  Messrs Zhe Zhe and Sword could afford such an advertisement today):

 

 

BTW, paid less than $5 for the tube.

Have fun!

 

Could not resist adding this picture of a 1947 Crosley cabriolet:

http://www.barrett-jackson.com/staging/carlist/items/Fullsize/Cars/139508/139508_Front_3-4_Web.jpg

And a 1942 Crosley Liberty Sedan

http://files.conceptcarz.com/img/Crosley/42-Crosley_Deluxe-CB-42-DV-08_HHC_02.jpg 


Edited by mordy - 1/7/14 at 6:53pm
post #4614 of 10501

does anyone know the original manufacturer of "Delta 6080" tubes? they are labled "Delta 6080" and "USA". any idea?

post #4615 of 10501

Hi LA,

 

It appears that Delta was a rebrander. Therefore, it could be any US manufacturer. Look for a three digit manufacturing code such as 312 or 374 etc. Only way to identify tube without this code is to compare it to a known source that looks identical.

post #4616 of 10501

Quick comparison of premium 6DJ8 tube sizes that should help explain the "tall bottle" expression I've read about a few times:

 

 

From left to right:

- Amperex US 6922, 1962 -> regular glass "bottle" height

- Philips Holland E188CC, 1960 -> regular glass "bottle" height

- Amperex Holland 6922, D-getter, 1959 -> tall "bottle" height (tallest of the four, with a distinct balloon-like top)

- Amperex Holland 6922 "Pinched Waist", D-getter, 1958 -> tall "bottle" height (higher than later tubes, but quite not as tall and round top as the D-getter 6922)

 

Just food for thoughts, could come in handy for ebay lurkers...

 

Btw, the Philips Holland E188CC are up for sale (need cash for imminent long trip to Japan lol). It's a - matched NOS NIB - pair, but it could be dissociated if two people were interested in a single tube. Ya nevah' know...

 

http://www.head-fi.org/t/698861/flash-sale-philips-holland-e188cc-matched-nos-nib-1960

post #4617 of 10501
Quote:
Originally Posted by mordy View Post
 

039?

 

That's YWW, but sometimes only weeks 13, 26, 39, 52 were used, so 39 could mean 3rd quarter.

 

Funny looking vehicles those Crosleys.

post #4618 of 10501
Quote:
Originally Posted by mordy View Post
 

Hi LA,

 

It appears that Delta was a rebrander. Therefore, it could be any US manufacturer. Look for a three digit manufacturing code such as 312 or 374 etc. Only way to identify tube without this code is to compare it to a known source that looks identical.

thanks man.

actually I have Tung-Sol, RCA, Telefunken, Delta and a Russian brand 6080/6AS7 tubes and I've compared all of'em to Delta but none of them is identical to Delta. I have an image of Delta which I used in a project. I appreciate if anyone could help to identify this tube:

 

post #4619 of 10501
Quote:
Originally Posted by mordy View Post
 

EOM? Maybe May 1950/60?

 

Yep. E0 = May 1950. Probably. In this case. The date of manufacture.

post #4620 of 10501

Hi Oskari,

 

The first tube of this type appeared in 1941, the 0 could not be 1940. What's your feeling, is it 1950 or 1960? The green print is supposed to be less common.

Sorry, I did not read the second post when I replied - thanks.


Edited by mordy - 1/8/14 at 8:22am
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