[bbmiller]

Hello
 If you look at the pinouts of the stock 6H30PI power tube (for a little dot MK IV amplifier) and the 12ax7eh they look identical except that the 12ax7eh has a wire going to pin nine of the tube which is said to make it a  6V or  12 V heater tube. But I do not know if my little dot MK IV amplifier comes with that pin already grounded to let you use this type of 12 vote tube. So does the little dot MK IV amplifier come with this pin already grounded so that this tube would become a plug-and-play power tube. If it doesn't how hard would this be to do?
 
A Pinouts for the 6H30PI can be found here.
 
A pinouts for the 12ax7eh can be found here.
 
In the head FI The Reference 6SN7 Thread the review I am posting below sounds excellent.
Quote

NEW STOCK – Electro-Harmonix EH6SN7 [PHOTO HERE]
[black plates, black base, black labels on glass, top getter]
● “The Electro Harmonix were the most dynamic in the MPX3 . The Bass is also the best and biggest of the three; quite detailed and tight. Midrange is also full of detail air and transparency up and down the range. Gets a little too bright in my system at times, but generally the most fun and involving tubes to listen to so far for me.” –bobjew
● “With the Electro Harmonix 6SN7's in current production, there is no need to suffer.” –Hirsch
● “They are fast-paced tubes with a bit of a heavy bass and ired with a slower driver tube the combo sounds quite nice.” –donovansmith
● “I came across a new 6SN7 tube by Electro-Harmonix and it sounds great. This tube seems to be a very good copy of the Sylvania VT231.It has killer bass and an excellent midrange and vocal performance. It warms up quickly and is not noisy or microphonic at all. It is an excellent value at $10.00 a pop. […] The build quality is high and they are very, very closely matched as tested on my tube tester. These get a "best buy" recommendation from Tuberoller. Try them before dropping big bucks on the Ken-Rads or CBS Brown or Red based tubes.” –Tuberoller
● “The biggest finding is that the Electro-Harmonix 6SN7 tube is about as good as a Syl 6SN7GTB.” –scottpaul_iu

NEW STOCK – Electro-Harmonix EH6SN7 Gold Pins [PHOTO HERE]
[gold pins, brown base, otherwise identical to non-gold pin version]
● “Aside from the obvious differences between the tubes– gold plated pins and the new goldish colored base; they look exactly the same. The model number is the same. The box has the same graphics with the addition of "gold pin" and printed in gold instead of black. Not surprisingly, they also sound very similar.” –bobjew

So does all that boil down to an almost identical sounding tube to the the stock little dot  IV MK SE  power tube? Has anybody heard  this tube? If I like the stock power tube will I like this tube and it's much cheaper price?
 
PS whoops I now realize what I did when I reviewed the post I just posted. I posted what is said, but about the octal version of this tube but I was looking at the nine pin mini package version when I got enthused about what could be a cheaper version of the stock power tube on eBay. Well perhaps you can tell me what you think of both I also have a pair of octal adapters just sitting there ready to use should I have to.
 
OK I finally think I'm getting my reviews straight between the mini nine pin version and the octal's. They seem to like the mini nine pin version@Amazon.com. Reviews to numerous to post, but here is the link. It is said to be a black Friday deal and as of this moment it is black Friday.

 

[gibosi]

  Hello
 If you look at the pinouts of the stock 6H30PI power tube (for a little dot MK IV amplifier) and the 12ax7eh they look identical except that the 12ax7eh has a wire going to pin nine of the tube which is said to make it a  6V or  12 V heater tube. But I do not know if my little dot MK IV amplifier comes with that pin already grounded to let you use this type of 12 vote tube. So does the little dot MK IV amplifier come with this pin already grounded so that this tube would become a plug-and-play power tube. If it doesn't how hard would this be to do?

 
In short, no, you cannot simply plug 12AX7's into your LD. Pin 9 on the 6H30PI is connected to an electrostatic shield. Pin 9 on the 12AX7 is connected to the heater circuit. And thus, in your LD power tube sockets, the heaters are connected to pins 4 and 5. In order to run a 12AX7 at 6V, it is necessary to tie pins 4 and 5 together, and then connect the heaters to pin 4 (or pin 5) and pin 9.
 
But there is no reason for despair... There are adapters!
 
For example:
 
http://www.ebay.com/itm/Two-adapters-for-12AU7-ECC82-to-instead-6CG7-6AQ8-ECC88-TUBES-amplifier-/261667818185?
 
When searching for adapters, it is important to remember that 12AU7, 12AT7 and 12AX7 all have the same pin-out. And likewise, 6CG7, 6AQ8, ECC85, 6DJ8, ECC88, 6N23P, 6N1P and 6H30PI all have the same pinout.
 
That said, the 12AX7, drawing only 0.3A, is probably not a good candidate for a power tube. But with high Z cans, it might not be all that bad....

 

[MIKELAP]

Would any of you guys have the 2 letter date codes used  for RCA tubes in mid 50's and again in the mid 60's. Thanks .

 

[MIKELAP]

Gibosi you had a link to RCA  date codes post # 2587 page 173 but link is not active anymore do you still have those date codes.Thanks. 

 

[gibosi]

  Would any of you guys have the 2 letter date codes used  for RCA tubes in mid 50's and again in the mid 60's. Thanks .

 
http://pax-comm.com/rcadates.pdf
 
Evidently, it is possible to date RCA tubes by looking at the etched octagram and noting where there are breaks in the lines. I have noticed these breaks, but to my knowledge, the "key" to this coding is not available on the internet.
 
So it appears that the best we can do is determine the date of shipment. So for example, I have a RCA 6FW8, which is a plug-in replacement for a 6DJ8/ECC88. The two-letter code is "LS". Looking at the table on the third page (actually page #18) I see that my tube was shipped in March, 1960. So while I don't know the precise date of manufacture, it was sometime before that shipment date, perhaps a few weeks or months.
 
edit: typo

 

[gibosi]

A nice Telefunken 6463 arrived in today's mail and I am pleased to say that it lights up and plays
 

 
And I wonder if anyone else is running 6350, 6463 or ECC813 tubes? Again, if you have a breadboard socket, it is easy to reconfigure it for these tubes. As I have recently gone back to school to get started in a new career, I haven't been able to spend much time listening to my system. But I can say that the Sylvania 6350's are terrific tubes, and I have high hopes for this Telefunken.
 

 

[siles1991]

I want to kick my MKIV SE up a notch and I have no idea how after being out of the scene for so long T.T. Would the 6HM5's be better than my current RCA 6DT6A and Valvo's?
Or should I just go for the C3gS's with adapters?

 

[gibosi]

  I want to kick my MKIV SE up a notch and I have no idea how after being out of the scene for so long T.T. Would the 6HM5's be better than my current RCA 6DT6A and Valvo's?
Or should I just go for the C3gS's with adapters?

 
It really depends on how much you are willing to spend? A pair of 6HM5's are dirt cheap, and in my opinion, better than the 6DT6. But a pair of C3g's sound significantly better, arguably end-game as far as drivers go. So again, it really depends on how much you are willing to spend? Perhaps $15 for a pair of 6HM5? or $130 for Cg3?
 
http://www.head-fi.org/t/563884/little-dot-tube-amps-vacuum-tube-rolling-guide/6000#post_10512665
 
Evidently, adapters are no longer available from "happydiy998", but I see that"tubemalls" has them for a better price. I have purchased other adapters from this vendor in the past and so expect these C3g adapters to be fine.
 
http://www.ebay.com/itm/2piece-Gold-plated-C3G-TO-6AK5-tube-converter-adapter-/191424601510?

 

[MIKELAP]

  I want to kick my MKIV SE up a notch and I have no idea how after being out of the scene for so long T.T. Would the 6HM5's be better than my current RCA 6DT6A and Valvo's?
Or should I just go for the C3gS's with adapters?

I 've been using the C3GS as drivers and the 6SN7with adapters as power tubes and i would say it the best sound i've  gotten out of this amp(MK3) yet .Electro Harmonix 6H30pi sound good to But if you get into C3GS they tend to be fragile when inserting in adapters so NO WIGGLING the tube when inserting or removing it might break the glass around the pins .                                                                                                                                                

 

[siles1991]

   
It really depends on how much you are willing to spend? A pair of 6HM5's are dirt cheap, and in my opinion, better than the 6DT6. But a pair of C3g's sound significantly better, arguably end-game as far as drivers go. So again, it really depends on how much you are willing to spend? Perhaps $15 for a pair of 6HM5? or $130 for Cg3?
 
http://www.head-fi.org/t/563884/little-dot-tube-amps-vacuum-tube-rolling-guide/6000#post_10512665
 
Evidently, adapters are no longer available from "happydiy998", but I see that"tubemalls" has them for a better price. I have purchased other adapters from this vendor in the past and so expect these C3g adapters to be fine.
 
http://www.ebay.com/itm/2piece-Gold-plated-C3G-TO-6AK5-tube-converter-adapter-/191424601510?

 
 

  I 've been using the C3GS as drivers and the 6SN7with adapters as power tubes and i would say it the best sound i've  gotten out of this amp(MK3) yet .Electro Harmonix 6H30pi sound good to But if you get into C3GS they tend to be fragile when inserting in adapters so NO WIGGLING the tube when inserting or removing it might break the glass around the pins .                                                                                                                                                

 
I want something end-game so i'll prolly go straight for the CG3's. Thanks for the links ^_^ Power tubes i'll prolly wait till mine dies out haha. Im using the MKIV SE will I need the additional adapter on top of the adapter to fit it in?

 

[MIKELAP]

   
 
 
I want something end-game so i'll prolly go straight for the CG3's. Thanks for the links ^_^ Power tubes i'll prolly wait till mine dies out haha. Im using the MKIV SE will I need the additional adapter on top of the adapter to fit it in?

 

   
 
 
I want something end-game so i'll prolly go straight for the CG3's. Thanks for the links ^_^ Power tubes i'll prolly wait till mine dies out haha. Im using the MKIV SE will I need the additional adapter on top of the adapter to fit it in?

You can remove your tube cages on MK4

 

[Acapella11]

  I want to kick my MKIV SE up a notch and I have no idea how after being out of the scene for so long T.T. Would the 6HM5's be better than my current RCA 6DT6A and Valvo's?
Or should I just go for the C3gS's with adapters?

Mikelap and Gibosi beat me to it

 

[hypnos1]

   
 
 
I want something end-game so i'll prolly go straight for the CG3's. Thanks for the links ^_^ Power tubes i'll prolly wait till mine dies out haha. Im using the MKIV SE will I need the additional adapter on top of the adapter to fit it in?

 
Hi s1991.
 
Yes...end-game indeed IMHO...
 
As MIKELAP says, you can just remove the 'cages'...and the plate, of course...
 
And you are VERY lucky that gibosi has found that new source for the adapters!...
 
Again, as MIKELAP says, you must be EXTREMELY careful inserting the tubes into the adapter...if they won't go in fairly easily with a STRAIGHT push, loosen the socket hole connectors - I found a good method was to use a small 1.5mm screwdriver (as in those spectacle repair kits) to prise them open a bit more. Just work it in and out until it inserts without too much effort, and you should then be safe...I would hate for you also to lose big $$$$$$ -  as a few of us have already!
 
Then...ENJOY!!

 

[hypnos1]

   
It really depends on how much you are willing to spend? A pair of 6HM5's are dirt cheap, and in my opinion, better than the 6DT6. But a pair of C3g's sound significantly better, arguably end-game as far as drivers go. So again, it really depends on how much you are willing to spend? Perhaps $15 for a pair of 6HM5? or $130 for Cg3?
 
http://www.head-fi.org/t/563884/little-dot-tube-amps-vacuum-tube-rolling-guide/6000#post_10512665
 
Evidently, adapters are no longer available from "happydiy998", but I see that"tubemalls" has them for a better price. I have purchased other adapters from this vendor in the past and so expect these C3g adapters to be fine.
 
http://www.ebay.com/itm/2piece-Gold-plated-C3G-TO-6AK5-tube-converter-adapter-/191424601510?

 
Hey g...WELL FOUND!...Those adapters look MUCH better - AND cheaper....GENIUS! 

 

[superdux]

still have some C3G for a bargain price if anyone is interested.