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Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 339

post #5071 of 7546
Quote:
Originally Posted by TrollDragon View Post
 

After looking at the datasheet for the TI chip http://www.ti.com/lit/ds/symlink/lm2596.pdf bottom of page 12 provides resistor and inductor calculations for variable voltage, this pot or resistor has to have short leads and be close to the chip. This will eliminate the use of an external regular size pot unless it can be connected with very short leads.

 

The number from your pot shows it to be 20K, if you only measure 11K then there are other board components affecting the measurement.

 

Sounds like if the tube hums in both amps then it is probably the tube itself.

Thanks for the info i need to wait until my other regulator and Display panel arrived the new regulator is the one that will be built inclosed with display panel and for the HUM it's the 6SL7 causing the hum.Again THANK YOU!

post #5072 of 7546
Quote:
Originally Posted by i luvmusic 2 View Post
 

Thanks for the info i need to wait until my other regulator and Display panel arrived the new regulator is the one that will be built inclosed with display panel and for the HUM it's the 6SL7 causing the hum.Again THANK YOU!

 

As MIKELAP said some tubes just hum, especially in the 6SL7/6SN7 family.

 

best to ask your vendor before purchasing.

post #5073 of 7546
Quote:
Originally Posted by mordy View Post
 

Bought a grab bag of ten 6SN7 tubes. One turned out to be a re-branded Japanese made tube. I have trouble finding information about Japanese octal tubes. Here are a couple of pictures. Can anybody tell me who made it and when?

 

There is no information on the base. Brand Channel Master 6SN7GTB. Only inscription is J90 and Japan.

 

I can't find enough photos to be sure but my guess is Toshiba. If not Toshiba, then possibly Hitachi.

 

You can see typical black-plate Hitachis (ITT-branded) and some grey-plate Toshibas at http://www.head-fi.org/t/479031/6sn7-tube-addicts/1830

post #5074 of 7546
Quote:
Originally Posted by gibosi View Post
 

 

If... I get a pair of these, I would like to remove the top metal cap, but is it possible to easily do so without disturbing the metal base?

 

Hi folks.

The adapters for the C3gSs are done (phew), so here are some photos & tips for anyone interested...

 

gibosi - hope this shows how easy it is in fact to release tube from ugly canister...

 

If you (or anyone) wish to re-attach the metal base, note the position of the 3 gaskets (pins 2, 5, and7), which may well fall out on extraction! (Second photo).

 

 

 

 

Quote:
Originally Posted by Oskari View Post
 

 

It's quite a brilliant design that 'marker' being a spigot in itself for the socket that is the bottom metal part of the tube.

 

The raised marker on the glass underside is not very clear, but is visible enough to show the 1-8 position - 1, of course, (sorry to those much more experienced than I) being to the left and running clockwise to 8. The metal base also has one slot (pin 6) of a different shape to fit the tube base raised seats.

 

 

You might just be able to see the tiny pieces of Teflon tube (leftover from speaker cable construction) I used to hold the silver wire to the tube pins for soldering, plus (hopefully) to give some mechanical connection also. A bit of 'white tack' - like plasticine - over the precarious protrusion - offers some protection but, of course, still needed to be treated warily!

 

 

Next, some tape around the pins to contain the first dose of 2-part rapid-setting resin - the joints MUST be well solidly bedded before even thinking of bending those would-be pins!...

 

 

Finally, over the wire/cum pins went half a 7-pin ceramic socket then a small, drilled disc of 5mm plastic (from an old chopping board) - 5mm being the socket inset, on the MKIV at least. For the last enclosure I used a piece of 26mm internal diam. aluminium tube (from some old tree loppers - well, necessity is the Mother...etc.etc.), suitably mauled at the rear to provide a gap (so who's gonna see it?!) for pouring in the final resin sealant. A snip of the wire pins to 7mm and a smoothing of any burrs...

(Edit...internal diam. changed to 26mm)

 

et voila!

 

 

(The tube is sitting in a glass egg-cup, in case you were wondering!).

The finished article doesn't look too out-of-place on the LD?...But some lovely, large, curvy rectifier-type tubes behind would certainly look much better - but after what I paid for those 6N30P-DRs, the look will have to stay!!

 

 

I must admit this job is a bit tricky, but I myself am quite a novice to this sort of thing (especially soldering). But with due care and diligence; careful planning; more care and diligence; patience and soldering practice, if necessary, this is not TOO difficult a task for most people. Using a loctal socket would be safer than attaching direct to the tube pins, that's for sure, but would make for a somewhat bulkier adapter... Otherwise, gibosi's 'breadboard' method , to a pair of Vector sockets, may suit those who do not feel confident in such construction. But I am sure this route must degrade the end result somewhat...especially if TOP grade wire isn't used. I firmly believe the 1.2mm silver wire I had doubling up as the pins has contributed to the magical sound I am now getting (or perhaps I'm deluding myself!...).

Whatever, I really do hope someone else gives these amazing tubes a try...

 

 

 

 

 

 

Quote:
Originally Posted by mab1376 View Post
 

 

Did you test the cg3 vs the cg3s?

 

also what is the price you paid if you don't mind me asking, they don't seem to have a price posted anywhere.

 

-edit-

 

i found the price list, looks like $40.86 each form JAC music or $66.01 each for the c3gs for the Siemens, Telefunken are absolutely ridiculous pricing!

 

(That's after a quick currency conversion from the euro using google, based on their "Export" price)

 

http://www.jacmusic.com/html/order/jacmusic-pricelist.PDF

 

With just 15hrs on the C3gSs, I must admit (and I just can't believe it possible) they are sounding even better than the 'ordinary' ones. I suppose the only way I can describe the difference is there seems to be more weight to the overall sound - especially in the bass (plus a bit more detail) and mids. But with no adverse effect on the high end either, nor the wonderful spacious airiness and pin-point imaging...how do they do it? There is also even more detail - the already amazing handling of transients and micro-detail goes to another level.

In other words, if you do go for C3gs, the 'S's are the ones to possibly keep looking for - if they do surface , and the PRICE IS RIGHT!  But even if not, the 'plain' ones are still utterly wonderful and would not disappoint, I am sure.

ps.  The S's tops are slightly flatter than the plains - otherwise they look totally identical.


Edited by hypnos1 - 2/19/14 at 12:12am
post #5075 of 7546

Hi Oskari,

 

Thanks for the info and the pictures. The tube I have does not match any of the pictures - especially the mica plates are different.

 

I guess it is safe to say that it was made by MaHiTo (Matsushiita/Hitachi/Toshiba) LOL. 


Edited by mordy - 2/18/14 at 4:56pm
post #5076 of 7546

Received an ECC40 today. This is an 8-pin double triode (6.3V, 0.6A) with what is called a "Rimlock" base (B8A). All the pins are equidistant and evidently, the little glass nub close to the base is used for alignment. The groove where the foot is joined to the bottle indicates that it was manufactured using Philips production equipment. For example, tubes manufactured by Tungsram do not have this groove.

 

Apparently, this tube was designed by Philips to replace the 6SN7GT, but it seems it was not a commercial success, and had a production run of only 3 years, from 1948 through 1951 (according to one source). And interestingly, "Made in Holland" is silk-screened on this tube, but the tube code (+9B8) suggests it was manufactured by La Radiotechnique, Chartres, in 1949.

 

From Google, a number of people have reported that this is a very good tube for audio, but unfortunately, my adapter is still sitting in San Francisco....

 

Edit: I can't believe that this tube was manufactured in 1949. To my mind, the 0-getter and 4-digit Phililps tube code suggests 1959 or even 1969. Perhaps Oskari will be able to shed more light on this....  :)

Edit2: Oh, he did!! And I will another look at the tube code.

 

 


Edited by gibosi - 2/18/14 at 3:24pm
post #5077 of 7546
Quote:
Originally Posted by hypnos1 View Post

 

The adapters for the C3gSs are done (phew), so here are some photos & tips for anyone interested...

 

Thanks for the very informative post!

 

As I am quite comfortable with ugly external sockets and an auxiliary heater PS, I am inclined to try a pair of C3ms. They are fairly plentiful and relatively inexpensive, perhaps due to the fact that they require 20V heaters. However, I am still quite enamored with 6SN7s and eager to hear my new ECC40, so these C3-pentodes (C3m, C3o and C3g) will probably sit on the back burner for a bit longer. :)

post #5078 of 7546
Quote:
Originally Posted by gibosi View Post
 

Received an ECC40 today. ...

 

Apparently, this tube was designed by Philips to replace the 6SN7GT, but it seems it was not a commercial success, and had a production run of only 3 years, from 1948 through 1951 (according to one source). And interestingly, "Made in Holland" is silk-screened on this tube, but the tube code (+9B8) suggests it was manufactured by La Radiotechnique, Chartres, in 1949.

 

Rimlock tubes were common in Europe, for a while.

 

Unless the date code is somehow exceptional, this must be a 60s or later code. That's because there's a character in the week number position. The week number, however, should be 1, 2, 3, 4 or 5, not 8. Can you check this?

 

What does the other part of the code look like?

post #5079 of 7546
Quote:
Originally Posted by Oskari View Post
 

 

Rimlock tubes were common in Europe, for a while.

 

Unless the date code is somehow exceptional, this must be a 60s or later code. That's because there's a character in the week number position. The week number, however, should be 1, 2, 3, 4 or 5, not 8. Can you check this?

 

What does the other part of the code look like?

 

Looking more carefully, that 8 is actually a 3. And the rest of the tube code is LC4 = ECC40, revision 4. 

post #5080 of 7546
Quote:
Originally Posted by gibosi View Post

 

Looking more carefully, that 8 is actually a 3. And the rest of the tube code is LC4 = ECC40, revision 4. 

 

Thanks! Probably 1969 then (rather than 1979). Do you agree?

post #5081 of 7546
Quote:
Originally Posted by Oskari View Post
 

Thanks! Probably 1969 then (rather than 1979). Do you agree?

 

Yes, 1969 makes the most sense to me. The only thing that seems a bit off is this implies there were only 4 revisions since the tube was introduced some 20 years earlier. But since the tube seems not to have been nearly as important to Philips as tubes such as the ECC82 and ECC88, then I would guess it is likely that very few resources were devoted to its development and improvement over that period of time.

post #5082 of 7546
Quote:
Originally Posted by gibosi View Post
 

 

Thanks for the very informative post!

 

As I am quite comfortable with ugly external sockets and an auxiliary heater PS, I am inclined to try a pair of C3ms. They are fairly plentiful and relatively inexpensive, perhaps due to the fact that they require 20V heaters. However, I am still quite enamored with 6SN7s and eager to hear my new ECC40, so these C3-pentodes (C3m, C3o and C3g) will probably sit on the back burner for a bit longer. :)

 

Thanks for your reply, gibosi.

 

Considering your marathon with different tubes, I can certainly understand another project needing to take its place in the queue on that (large!) burner...a shame really...

 

However, methinks you should definitely be awarded the honour of 'Master Roller' for all your tremendous efforts - WELL DONE, and long may you prosper!

 

 

mab1376 :

 

With another 17 hours on the C3gSs, I continue to be totally blown away by this family...in addition to the differences I mentioned previously (all of which are even greater!), the already unnerving ability to resolve difficult elements such as a fast drum run with total aplomb is also surpassed with the Ss. As is the case with reproducing a note from clean attack/strike thru delicious decay throughout the frequency range (but especially noticeable with piano), with no single one dominating at the expense of others...And as for 'holographic sound'..I am lost for words now. All I can say (to anyone) is KEEP SEARCHING for the 'Ss' if you decide to give these C3gs a try. These things (especially the Ss) are lightyears ahead of where we started from.

 

Cheers from someone currently on another planet!!

post #5083 of 7546
Glad I bought c3gS...
I think I wont be disappointed with the change i plan to make to the tubes.

Btw, do you think the 6sn7 as power tube does make big difference vs my 6h30?

Oh and forgot to thank for the explanation of tube pin abbreviations!
Edited by CollectoR13 - 2/19/14 at 10:11am
post #5084 of 7546
Quote:
Originally Posted by hypnos1 View Post

mab1376 :

 

With another 17 hours on the C3gSs, I continue to be totally blown away by this family...in addition to the differences I mentioned previously (all of which are even greater!), the already unnerving ability to resolve difficult elements such as a fast drum run with total aplomb is also surpassed with the Ss. As is the case with reproducing a note from clean attack/strike thru delicious decay throughout the frequency range (but especially noticeable with piano), with no single one dominating at the expense of others...And as for 'holographic sound'..I am lost for words now. All I can say (to anyone) is KEEP SEARCHING for the 'Ss' if you decide to give these C3gs a try. These things (especially the Ss) are lightyears ahead of where we started from.

 

Cheers from someone currently on another planet!!

 

Thanks for the info, I'll definitely consider them if i can make an easy adapter using a LOCTAL socket.

 

For now i have my PSU board on the way and I'm going to use the 6SU7GTY tube i have on the way with two 6SN7GTB's as power tubes.

post #5085 of 7546
Quote:
Originally Posted by CollectoR13 View Post

Glad I bought c3gS...
I think I wont be disappointed with the change i plan to make to the tubes.

Btw, do you think the 6sn7 as power tube does make big difference vs my 6h30?

Oh and forgot to thank for the explanation of tube pin abbreviations!

 

You lucky feller - I am sure those C3gSs will blow you away. Well chosen...

 

The general concensus (for the LD anyway) seems to have been that the power tubes  - unless paying BIG bucks for the 6N30P-DR 'Supertubes' - do not have a great influence on the sound, certainly if you have the gold-pin 6H30Pi-EH. However, Artsi seems to like the 6SN7s and mab1376 is going to be trying some , so perhaps we shall have some comparisons coming in very soon?...Should prove very interesting.

 

And I believe it was gibosi who helped you re. the pins, so it's thanks to him...

 

Quote:
Originally Posted by mab1376 View Post
 

 

Thanks for the info, I'll definitely consider them if i can make an easy adapter using a LOCTAL socket.

 

For now i have my PSU board on the way and I'm going to use the 6SU7GTY tube i have on the way with two 6SN7GTB's as power tubes.

 

Yes mab, PLEASE consider them seriously...I am desperate for some other opinions!! If you do go ahead, please feel free to get in touch if you have any questions/doubts re. the tube and/or  adapter. Perhaps I might be able to help...(this goes for anyone else who wants to give them a try).

Look forward to your impressions of the 6SN7GTBs as power tubes.


Edited by hypnos1 - 2/19/14 at 12:00pm
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