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Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 343

post #5131 of 8776
Quote:
Originally Posted by hypnos1 View Post

 

So you like syrup eh? Me - I prefer honey! Preferably with lots of different, subtle flavours..

 

lol.. Well yes, sometimes the RCA is a bit too syrupy for sure, but it does a wonderful job of recreating a sense of being in a live performance space, and on some recordings, it is quite spectacular. However, the 6SN7 that spends the most time in my LD is a 1945 short-bottle Sylvania 6SN7W. It compares very well with my Heerlen-made E80CC, which is the most neutral and linear tube I have, with similar detail, but a stronger and more propulsive bass. So as of this moment, these are my top two tubes.

 

Eventually, I do intend to get to the C3-pentodes. But as they will require a significant reworking of my current configuration, swapping two loctal sockets for one 9-pin, I want to wait until I have finished exploring the ECC40s....

 

Cheers,

post #5132 of 8776

Has anyone tried any VT-99 tubes?

post #5133 of 8776
Quote:
Originally Posted by mab1376 View Post
 

Has anyone tried any VT-99 tubes?

 

I haven't, but they have gotten a fair amount of love over in the 6SN7 Tube Addicts thread. As it is simply a 6F8G, all you need is an octal socket and an adapter like this:

 

http://www.ebay.com/itm/Tube-adaptor-6F8G-to-6SN7-Socket-/400667131972?pt=Vintage_Electronics_R2&hash=item5d499f4044

post #5134 of 8776

6F8G are great tubes if you have quiet one, BL63 better again. Re the former Tung Sol are the prefered with round plates but I have found many other good examples out there with and without both round plates and Tung Sol logos.

post #5135 of 8776
Quote:
Originally Posted by gibosi View Post
 

 

I haven't, but they have gotten a fair amount of love over in the 6SN7 Tube Addicts thread. As it is simply a 6F8G, all you need is an octal socket and an adapter like this:

 

http://www.ebay.com/itm/Tube-adaptor-6F8G-to-6SN7-Socket-/400667131972?pt=Vintage_Electronics_R2&hash=item5d499f4044

 

so its an octal but different pinout? and whats the top cap in the adapter for?

post #5136 of 8776
Quote:
Originally Posted by mab1376 View Post
 

so its an octal but different pinout? and whats the top cap in the adapter for?

 

Again, I have no experience with this tube, but yes, the pin-out is different and thus, an adapter is needed. The biggest difference is that there is an element, or perhaps one might say, a very fat pin located on top of the tube, which corresponds to grid 1.

 

wa22_6f8g.jpg 

post #5137 of 8776

Hi Artsi,

 

Here is a colorful idea for your next project. All you need is a WWII jerry can:

 

Triode-Festival-1.jpg

 

LOL

post #5138 of 8776
Quote:
Originally Posted by mordy View Post

Hi Artsi,



 



Here is a colorful idea for your next project. All you need is a WWII jerry can:



 



Triode-Festival-1.jpg



 



LOL


 



Usually those jerry cans smell like diesel for a long time. But i have plans to do normal stereo tube amplifier with headphone output. It is little bit different to work with output transformers, but we'll see what is going to happen.
post #5139 of 8776

Hi,

 

Little quiet on the forum; we need a little action.

 

Here is a he-man tube, the indomitable 833C: (plz note the size compared to a regular tube)

 

 

 

DSCF1607.jpg

 

PICT0303.jpg

 

This is a broadcast tube that can generate some serious high voltage; 1200-2000V +

 

DSCF1753.jpg

 

 

Here is an application for stereo.

 

PICT0333.jpg

 

However, personally, I think that it is a bigger achievement to get $1000 sound from a $200 amp than to get great sound from an amp costing tens of thousands of $$......

post #5140 of 8776

Yes, it has been quiet... So maybe I can stir things up a bit? lol

 

I have been thinking about whether it might be possible to use a rather different double triode, the E90CC, in our LDs. Users of Torpedo headphone amps

 

http://beezar.com/catalog/product_info.php?cPath=42&products_id=153

 

rate the E90CC to be the best tube available for that amp.

 

However, it has a common cathode, and evidently, there is no way to run it as a double triode in our LDs. When I first looked at this tube, and saw only 7 pins, I wondered how? Each triode typically takes 3 pins and then the heaters take 2 more for 8 pins! But in the E90CC, the two cathodes are tied together. So, this leads me to the idea of converting this double triode into a single triode, that is, finish the job by tying the two grids together and the two plates together in the socket.

 

Now.... my knowledge of electronics is just sufficient to get me into trouble... but not out of trouble!  lol...

 

So I will just throw this out and see if folks think this is crazy..

 

From what I have been able to figure out....  The plate resistance of the E90 is 4.5Kohms. So if we tie the two plates together, I guess the combined plate resistance would be 9.0Kohms? However, the ECC40 has a plate resistance of 9.3Kohms, and it works extremely well in my LD. So it would seem to me that the LD just might be able to handle a E90CC converted into a single triode...

 

TrollDragon and others.... what do you think?

post #5141 of 8776
Quote:
Originally Posted by mordy View Post

 

This is a broadcast tube that can generate some serious high voltage; 1200-2000V +

Here is an 833A DIY amp...

http://world-designs.co.uk/forum/showthread.php?t=5939

post #5142 of 8776
Quote:
Originally Posted by gibosi View Post

From what I have been able to figure out....  The plate resistance of the E90 is 4.5Kohms. So if we tie the two plates together, I guess the combined plate resistance would be 9.0Kohms? However, the ECC40 has a plate resistance of 9.3Kohms, and it works extremely well in my LD. So it would seem to me that the LD just might be able to handle a E90CC converted into a single triode...

 

TrollDragon and others.... what do you think?

Hey gibosi

 

Paralleling plates is like paralleling resistors the resistance will be half not double, so you will end up with an Rp of 2.25K

 

The parafeed amp does parallel the plates and the grids but it is designed to do such.

Sorry I don't know what the LD's minimum Rp value should be and can't say if this tube would be OK or not.

:beerchug:

post #5143 of 8776

I was thinking something along the lines of a 6D10, Compactron with three triodes in it, just ignore the middle triode and make a 12pin to dual 7 pin adapter and the heater is only 0.45A.

http://www.radiomuseum.org/tubes/tube_6d10.html

:beerchug:
 

post #5144 of 8776
Quote:
Originally Posted by TrollDragon View Post
 

Hey gibosi

 

Paralleling plates is like paralleling resistors the resistance will be half not double, so you will end up with an Rp of 2.25K

 

The parafeed amp does parallel the plates and the grids but it is designed to do such.

 

Sorry I don't know what the LD's minimum Rp value should be and can't say if this tube would be OK or not.

 

 

lol... So I got it backwards!

 

But even so, the 6DJ8 has a plate resistance of about 2.5K, so the E90CC just might be OK...  

post #5145 of 8776

I'm wondering what will happen if i switch the jumper from EF95 to EF91/92 setting with 6SN7 Tube.fireworks maybe?

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