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Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 140

post #2086 of 5908
Quote:
Originally Posted by ancientfire View Post

And where did you purchase the jumpers?


radio shack , under 2 bucks for 10, "DIP SHORTING JUMPERS"  , i believe gibosi provided a link a page or two back, for them off of ebay, 50 for about 3-4 bucks shipped

i'd like to find a match for this  tung sol 6028 :

 

i'm letting my fingers walk through the internet,  is this rare or something ??

post #2087 of 5908
Quote:
Originally Posted by gibosi View Post

 

And now that you are up to speed on the standard tubes, EF91, EF92, EF95 and 408A, it is time to move on to some of the non-standard tubes! :)


 well, i'm sure i'll get to that , i would like to find a mate , or be able to do something with the tung sol i have

there are so many types, brands, versions of tubes, the possibilities are endless , and its cheaper for the most part than buying different headphones, dacs, amps, etc 

post #2088 of 5908
Quote:
Originally Posted by jaywillin View Post

i'd like to find a match for this  tung sol 6028 :

 

i'm letting my fingers walk through the internet,  is this rare or something ??

 

I have never seen a Tung Sol 408A/6028...  I have the usual suspects: Northern Electric, Western Electric, and Sylvania Gold Brand/gold pins. However, I haven't listened to any of these in a long time.....

post #2089 of 5908
Quote:
Originally Posted by gibosi View Post

 

I have never seen a Tung Sol 408A/6028...  I have the usual suspects: Northern Electric, Western Electric, and Sylvania Gold Brand/gold pins. However, I haven't listened to any of these in a long time.....


it did kinda surprise me,not finding any others and now i'm just curious about it, here's a couple of better pics

 

 

well, one pic is better lol


Edited by jaywillin - 7/27/13 at 3:25pm
post #2090 of 5908
Quote:
Originally Posted by jaywillin View Post

it did kinda surprise me,not finding any others and now i'm just curious about it........

 

It seems they are not at all common. But in my experience, if I can't find something, I keep checking every day or so, and eventually they turn up....

 

In the meantime, triodes and heptodes are cheap and easy to find. :)

post #2091 of 5908
Quote:
Originally Posted by gibosi View Post

 

It seems they are not at all common. But in my experience, if I can't find something, I keep checking every day or so, and eventually they turn up....

 

In the meantime, triodes and heptodes are cheap and easy to find. :)


the last pair i just bought, the rca 5915, the first time i listened, it sounded terrible, nooooo bass, i had the amp's settings wrong

once corrected, boom, good sound ! lol

post #2092 of 5908
I recently decided to try to compare two of my current favorite tubes, the Siemens EK90 (unstrapped) and RCA 6AV6. I primarily listened to Diana Krall's "From This Moment On" with a nice big brass band behind her.
 

 

 

First some comments regarding comparing triodes and heptodes....
 
In short, comparing triodes to heptodes is normally very difficult with the LD. Opening up the amp to change jumpers is certainly a pain. Further, once you have changed jumpers, trying to compensate for any differences in gain from memory is very imprecise. However, I now have a pair of modified socket testers, strapping pins 5 and 7, so I no longer have to open up the amp. And the fact that the LD1+ uses tubes as buffers in front of an op amp, rather than amplifiers in front of output tubes, suggests that differences in gain are not as pronounced as with the LDIII and IV. In fact, I found these tubes seemed to have virtually the same gain on my amp.
 
While the following impressions are brief, I am hopeful they will still be of interest.
 
I found the the Siemens and RCA very similar on the low end. Further, they are similarly bright. Where they really differ is in the mid range. The Siemens are decidedly not warm and thus the mid range has a certain thinness to it. On the other hand the mid range on the RCA is rounder and a bit warmer, and to my ear, the RCA comes out on top.
 
Finding these two so similar, I then wondered how the RCA might compare to the Telefunken EK90.
 

 

I found the sound stage and instrument separation on the RCA to be virtually the same as that of the heptodes. Further, all three tubes have a very similar low end, low and solid, but the Telefunken has the same thin mid range similar to the Siemens, as opposed to the rounder mid range of the RCAs.  Further, the Telefunkens are brighter than both the RCA and Siemens. The added brightness of the Telefunkens does seem to add more air, but I am not sure more air is always good as these Telefunkens are sometimes just a bit too forward for my taste. To my ear, I preferred the RCA over the Telefunkens, as well.
 
So.... in the end, at this time, the RCA 6AV6 is my favorite tube.... for now... lol :)
post #2093 of 5908

making me itch on buying those to try them as well haha

post #2094 of 5908

Hi John,

Reading through some older posts and in one you mention that you use socket savers for the LDMKIII. Could you tell me where to get them?
 

post #2095 of 5908

Leeds Radio 68 North 7th Street Brooklyn NY 11249 tel: 718 963-1764

 

Test socket 7 pin miniature                           $7.00

 

http://leedsradio.com/parts-sockets.html#savers

post #2096 of 5908

Hi folks.

 

One final(?) observation re. the Siemens EH90 tubes.

Previously, I mentioned the superior sound coming from the pair with 'made in Germany' on, even though both pairs were supposedly Mullard (Blackburn)- made. Well, it would appear the difference is down to the one (of the non-'m.i.G') that had a very slight hum which did not disappear over time...having replaced it with another Philips-coded one (D9A, from Valvo, Hamburg).

This one also had the wider metal laterals of the 'm.i.G.' tubes, as seen through the rectangular holes, and as shown in my post on page 134.

Immediately the clarity; soundstage; instrument separation etc. returned, and especially the fabulous deep/tight bass...

 

Ergo, what at first seemed to be just a minor feature of the tube - not really intrusive in any way - was in fact having a VERY detrimental effect on the quality of sound.

Moral? I would think it is fairly safe to assume that ANY tube exhibiting such a hum (no matter how slight) - given that others are quiet - should be consigned forthwith, and replaced with as good a match - ( minus hum!!) -  as possible (hence the wisdom in never getting just a single pair, if at all possible - to my mind at least...).

 

Happy rolling, everyone.

 

ps. Am awaiting some Valvo EH90s, and can't wait to see how they compare to the 'Siemens'...

post #2097 of 5908

Fabbrica Italiana Valvole Radio Elettriche (FIVRE) was an Italian vacuum tube manufacturer that existed between 1932 and 1991. In later years they were bought up by Marelli, which produces ignition, suspension and racing parts for Ferrari and other makes. This must be the connection between FIVRE and Ferrari and the reason the boxes are red and black. (Or it could be that they copied the colors of the red and black RCA boxes since they had a long standing cooperative agreement with RCA.)

 

So here we have the ultra rare Italian made FIVRE 6BE6 heptodes that probably were manufactured in the 50's-60's. Is this tube the Ferrari of heptodes?

 

Burning in: The tubes were broken in at 9000RPM with a Marelli EF95 gearbox for 50 hours using the 6/7, NS, 2/7 and 1/7 gears. The air cooled engine ran cool, and no dangerous overheating occurred. While NS was a dud, the 6/7 rivaled the triodes in the very detailed treble department. The 2/7 was too treble skewed. The 1/7 gave the best acceleration times. Enough of car comparos...

 

These tubes are bass monsters. Deep powerful bass going down very low. If there is a kick drum in the recording, you are going to hear it.The mid range coolness disappeared during burn in and was replaced by a neutral thin mid range. The treble is absolutely outstanding, allowing you to hear new nuances in the music.There is a great wide 3D sound stage with excellent spatial separation and pin point imaging. However, the treble is ruthlessly revealing. If the recording is treble skewed it will destroy it. With a technically very well made recording these tubes sound fabulous, but with lesser sound quality brightly recorded  music they become glaring. These are macho tubes without sweetness in the mid range.

 

Edit 7/30: Another feature of these tubes that I did not come across before: Normally, when you turn up the treble or bass controls, the recording is "colored" by more treble or bass, but the the musical information is essentially the same. With these tubes, when turning up the tone controls it is like looking into a microscope; more and more details emerge in the treble and bass. (Usually when turning up or down the tone controls you hear more of or mask certain musical information, but these tubes add much more information than any others I heard. -Felt that I had to add this to the review.)

 

Not far from where I live is a Ferrari dealer. Once the local paper interviewed a salesman there and the reported asked. "How do you sell these very expensive, impractical cars that nobody really needs, and that basically are toys for adults?" Answered the salesman: "You don't sell the car, you sell yourself. If they like you they buy."

 

Night view of the 50 heures Le Valvole race. Notice the red hot exhaust from the four cylinder nikasil electron charged engines.

 

 

This tube may be for people who like a superbly detailed treble and hefty bass (AFB, r u there?) but personally I prefer a warmer, sweeter, more musical tube. With certain recordings it really shines, but the wow factor only comes through here and there.


Edited by mordy - 7/30/13 at 7:23pm
post #2098 of 5908
Quote:
Originally Posted by mordy View Post

Fabbrica Italiana Valvole Radio Elettriche (FIVRE) was an Italian vacuum tube manufacturer that existed between 1932 and 1991. In later years they were bought up by Marelli, which produces ignition, suspension and racing parts for Ferrari and other makes. This must be the connection between FIVRE and Ferrari and the reason the boxes are red and black. (Or it could be that they copied the colors of the red and black RCA boxes since they had a long standing cooperative agreement with RCA.)

 

So here we have the ultra rare Italian made FIVRE 6BE6 heptodes that probably were manufactured in the 50's-60's. Is this tube the Ferrari of heptodes?

 

Burning in: The tubes were broken in at 9000RPM with a Marelli EF95 gearbox for 50 hours using the 6/7, NS, 2/7 and 1/7 gears. The air cooled engine ran cool, and no dangerous overheating occurred. While NS was a dud, the 6/7 rivaled the triodes in the very detailed treble department. The 2/7 was too treble skewed. The 1/7 gave the best acceleration times. Enough of car comparos...

 

These tubes are bass monsters. Deep powerful bass going down very low. If there is a kick drum in the recording, you are going to hear it.The mid range coolness disappeared during burn in and was replaced by a neutral thin mid range. The treble is absolutely outstanding, allowing you to hear new nuances in the music.There is a great wide 3D sound stage with excellent spatial separation and pin point imaging. However, the treble is ruthlessly revealing. If the recording is treble skewed it will destroy it. With a technically very well made recording these tubes sound fabulous, but with lesser sound quality brightly recorded  music they become glaring. These are macho tubes without sweetness in the mid range.

 

Not far from where I live is a Ferrari dealer. Once the local paper interviewed a salesman there and the reported asked. "How do you sell these very expensive, impractical cars that nobody really needs, and that basically are toys for adults?" Answered the salesman: "You don't sell the car, you sell yourself. If they like you they buy."

 

Night view of the 50 heures Le Valvole race. Notice the red hot exhaust from the four cylinder nikasil electron charged engines.

 

 

This tube may be for people who like a superbly detailed treble and hefty bass (AFB, r u there?) but personally I prefer a warmer, sweeter, more musical tube. With certain recordings it really shines, but the wow factor only comes through here and there.

Magnifico signor mordy

post #2099 of 5908

Very nice indeed.

 

BTW SICTE and ATES also used red and black boxes.

FIVRE were based in Milano.

 

Marconi Italiana used Blue and red boxes.

 

Zenith had a factory in Monza.

post #2100 of 5908

Mikelap,

 

 

Pardon, è Mordicci, non Mordy
 

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