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Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 451

post #6751 of 10486

Yesterday took some time to compare three sub-miniatures, Raytheon 6832, Melz 6N16B-VR and Sylvania 7963. First, I should say that all these tubes are exceptional. Moreover, they are more similar than different. And the differences that exist are very subtle. So while I try to accentuate these differences below, in reality, they are quite small.

 

As before, I found the 6832 to be the least 3-D of the bunch. The stage is relatively flat. Imaging and layering is less precise, and there is a little less clarity. In complex passages, it was a little harder to separate each strand. That said, the tone is right, vocals have good body and warmth, it is a very nice tube, all in all.

 

At times, the 6N16B-VR can be breathtaking. Exquisite clarity and an almost magical 3-D space. There is a sense of immersion, being surrounded by the music, rather than the stage being somewhere in front of you. But... the vocals are a bit thin, and on some recordings, even a bit reedy. On most recordings, this is a supremely enjoyable tube, but once in awhile, I found the vocals to be a little grating. (I should say this is with Senns 700 and an LD 1+ with MUSES02 opamp.)

 

The best of the four sub-miniatures in my possession (including the Sylvania 6021) is the 7963. It has all the 3-D magic of the 6N16B-VR plus that warm, silky-smooth Sylvania mid-range. As cheap as these sub-miniatures are, I recommend all three. But if the choice is one, and only one, then the Sylvania 7963 is the way to go.

post #6752 of 10486
Quote:
Originally Posted by TrollDragon View Post

Well my take on the PS issue is that the heaters are probably getting a proper current now where they were underpowered before.

Driving the regulator from a 12V 4A supply will only ever give you 4A of output, dropping the voltage to 6 will not give you 8A of power... The regulator is converting the voltage, it still only has the rated supply amps to work with.

Which is why I have always recommended a 8A or higher supply for a 5A draw...

The easiest way to test this is to actually measure the current draw on the heaters, something I suggested with a diagram some 100 or more pages back... wink.gif

If you do use your meter to measure the current on the 6AS7's or any other tube for that matter, hook up your meter power up the tubes and take your reading, leaving a meter on the 10A current measurement too long will burn it out as it does get warm inside.

1. Set the meter for 10A scale and double check it.
2. Move your probes to the 10A connections double check them.
3. Connect the meter in series with the heater wires + or Red to the positive on your regulator, - or Black to the tube.
4. Power up the LD and observe the current draw as the tube heats up no more than 30 seconds.

If you get a brief reading after you turn on the amplifier then nothing, it is possible that the in rush current has popped the 10A fuse in your meter and you will need to replace it.

Expensive meters and Amprobe's are a different story but I don't think anyone has those except for "Mr. Fluke" who we havn't seen in a while... biggrin.gif

 

Glad you cleared up that heater power supply anomaly, TD - must admit I too was somewhat perplexed as to mordy's finding, lol!

post #6753 of 10486

This SUCKS! I just got home and my rig is not gonna be here until next week.:( 

post #6754 of 10486

Oh by the way this tube(None working Chatham 6080WB with Red LED inside)) i sold it for $15.:biggrin:

post #6755 of 10486

A word to those with the C3g as drivers...if you decide to go the 6AS7G route, with external heater power supply - which once again I implore you to take, if you haven't already - make sure you seek out the CHATHAM JAN CAHG tube. If ever a driver and power tube were made for each other, these most certainly were, lol! Even after all this time now, I continue to be amazed each and every listening session no matter what genre of music thrown at them. I feel no necessity whatsoever to blow hard-earned cash on the (over?) high-priced 5998/421A/A1834 family...but of course that's just my take on things. Suppose it's because the much more reasonably-priced Chathams have me in total awe...and luckily, they do seem to pop up now and then. My RCAs cannot compare, IMHO.

post #6756 of 10486
Quote:
Originally Posted by hypnos1 View Post
 

A word to those with the C3g as drivers...if you decide to go the 6AS7G route, with external heater power supply - which once again I implore you to take, if you haven't already - make sure you seek out the CHATHAM JAN CAHG tube. If ever a driver and power tube were made for each other, these most certainly were, lol! Even after all this time now, I continue to be amazed each and every listening session no matter what genre of music thrown at them. I feel no necessity whatsoever to blow hard-earned cash on the (over?) high-priced 5998/421A/A1834 family...but of course that's just my take on things. Suppose it's because the much more reasonably-priced Chathams have me in total awe...and luckily, they do seem to pop up now and then. My RCAs cannot compare, IMHO.

Do you have any good source for Chatham 6AS7G's?If so please share.THANKS! 

post #6757 of 10486

I wish he would ship to the UK but for for the US / Canada try

 

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=221485227989&ssPageName=ADME:B:SS:GB:1120

 

a bit of a bargain for some I think

post #6758 of 10486

THANK YOU ALL ! For the LINK i just contact the vendor.I need 4 pcs. and i have 3 on it's way from Vacuum tubes(bought all chatham they have) .net sometimes they can be over price but these ones i'am grabbing some.Again Thank You!:beerchug:

post #6759 of 10486
Quote:
Originally Posted by Nic Rhodes View Post
 

I wish he would ship to the UK but for for the US / Canada try

 

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=221485227989&ssPageName=ADME:B:SS:GB:1120

 

a bit of a bargain for some I think

 

Ye gods! At that price they're an absolute STEAL. As for not shipping to the UK...that just SUCKS, lol!!

post #6760 of 10486

I need to wait and see how much for the shipping.

4 6AS7G's should be no more than US$17.00-20.00 this what vac^um t@#e.net charge for 5 6AS7G's(3 Chatham and 2 RCA 6AS7G's) 

post #6761 of 10486

Hi TD,

 

Thank you for providing a rational explanation why the tubes sound better with a PS with the higher amp rating. The PS I am running now is rated 12V/14-15A, but I am only running a single 2.5A tube from it at the present. The old PS was rated at 19V 2.6A.

 

In conclusion, it appears beneficial to use a more beefy PS, and I am awaiting the results of other people trying this. Once you have a proper PS, it can can be modified in a couple of minutes without cutting or soldering.

 

Take a 1/2" 0.8 mm copper wire and bend it into a U shape. Locate the 20/24 pin plug and look for the single green wire in the entire tangle. Next to it on either side is a black wire. Push in the U shaped copper wire (a large paper clip cut to size could do the same job) into the connecting sockets for the green and black wires. Cover with electric tape.

 

Find a connector with a yellow and black wire (should be many of them; ignore other colors) and find a piece of wire that will fit both into the voltage regulator and the computer plug (you could double the the wire for a snug fit in the computer harness). Cover with tape. The yellow wire is + and the black wire is -; just connect to the corresponding connectors on the voltage regulator.

 

That's it; you are done! You will have a lot of extra wires coming out from the PS - I bundled them up and put the whole harness into a bag, but must admit that it doesn't look esthetically pleasing.

 

The increased punch in the bass and the increased clarity more than makes up for it.

post #6762 of 10486

Hi All,

 

Here is a partial answer to the question: When is Ebay sleeping?

 

In other words, are there times when you can get a better buy, or are there times when fewer people look for things to buy, resulting in less competition for bids?  On the flip side, are there times when you can expect to get fewer bids or less interest when selling?

 

The answer is simple and common sense, but maybe this knowledge will help you in snagging a good deal (or avoiding something to go for 99 cents).

 

Basically, your chances of getting a better buy is when people are busy with other things and don't have time to check Ebay. Such times are national holidays and Saturday nights when many people are busy doing other things. If you are selling something, avoid the auction to finish Saturday night or on the 4th of July, Thanksgiving etc.

 

On the topic of Chathams 6AS7 tubes, I notice that checking the sold listings for the last sixty days the least expensive tubes went for for $13, $14 and $20 (all prices incl shipping), so Nic's suggestion is certainly very worth wile. In June two Tung Sol 6AS7 tubes went for $15 and $17 incl shipping.

post #6763 of 10486

 No luck on the Chatham 6ASG's the seller is not replying to my email about shipping cost to Canada i was gonna buy 4 but then again i don't want to get rip off for the shipping it should not be more than US$20 for all 4 but then again some eba7er charged US $34.99 for 1 tube and some even charged import charges.I hope i will get a reply soon.

post #6764 of 10486
Quote:
Originally Posted by i luvmusic 2 View Post
 

 No luck on the Chatham 6ASG's the seller is not replying to my email about shipping cost to Canada i was gonna buy 4 but then again i don't want to get rip off for the shipping it should not be more than US$20 for all 4 but then again some eba7er charged US $34.99 for 1 tube and some even charged import charges.I hope i will get a reply soon.

 

This weekend is is a national holiday in the US, so the vendor may not get back to you until Monday. That said, the vendor would charge $14.00 to ship four tubes in the US, which I think is high....

post #6765 of 10486
Quote:
Originally Posted by gibosi View Post
 
Quote:
Originally Posted by i luvmusic 2 View Post
 

 No luck on the Chatham 6ASG's the seller is not replying to my email about shipping cost to Canada i was gonna buy 4 but then again i don't want to get rip off for the shipping it should not be more than US$20 for all 4 but then again some eba7er charged US $34.99 for 1 tube and some even charged import charges.I hope i will get a reply soon.

 

This weekend is is a national holiday in the US, so the vendor may not get back to you until Monday. That said, the vendor would charge $14.00 to ship four tubes in the US, which I think is high....

Sorry i for got about the US holiday.I hope it will not cost me arm and a leg for the shipping.:biggrin:THANKS! 

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