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Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 530

post #7936 of 10497
Quote:
Originally Posted by bbmiller View Post
 

I'm I right in thinking that  page 77 table is only for driving tubes? Has anybody assembled such a table the power tubes?


What is the process for Figuring out what power tubes are compatible for yourself?

Quote:

Originally Posted by mordy View Post
 

Some time ago we compared various power tubes for the LD MKIII. 6N6P, 6N6Pi, 6N6P-IR and 6H30-DR. The last two were the best, the IR tube being a best buy. However, what distinguished one tube over another was the bass detail and punch, and nobody mentioned how neutral sounding the tube was.

post #7937 of 10497
Quote:
Originally Posted by bbmiller View Post
 

I'm I right in thinking that  page 77 table is only for driving tubes? Has anybody assembled such a table the power tubes?


What is the process for Figuring out what power tubes are compatible for yourself?

 

To my knowledge, no one has put together such a table. In order to figure out for yourself, the most important factors are

 

1) Double triode

2) Separate cathodes (there are some double triodes such as the E90CC where the triodes "share" a cathode. These will not work.)

3) Heater current 1.0A or less

4) 6.3 Volts

 

I think that is about it, but if I am overlooking something, I am sure someone will let me know. :)

 

If the tube is not pin-compatible with the 6DJ8 and 6N30P, it should be a simple matter to purchase or make an adapter. For example, the 6SN7.

 

Have fun! :)

 

Edit: added 4)


Edited by gibosi - 10/18/14 at 3:53pm
post #7938 of 10497
Quote:
Originally Posted by gibosi View Post
 
If the tube is not pin-compatible with the 6DJ8 and 6N30P, it should be a simple matter to purchase or make an adapter. For example, the 6SN7.

 

Have fun! :)

 

Are there any databases which lets you search for tubes by pin arrangement? Do pin arrangements of vacuum tubes have names that can be search for in any way? On the Internet? On a page itself if you search for the recognizable pin arrangement name, say in certain very good datasheets?

 

What "are the to and from tube names" that are iconic for certain pin arrangement conversions adapters which are already made? Are there ones which are important for a little dot IV amplifier which haven't been mentioned on this thread?


Edited by bbmiller - 10/18/14 at 4:16pm
post #7939 of 10497
Quote:
Originally Posted by TrollDragon View Post

Here is a little tip, when you respond above quoted text instead of below, the next person can't quote your reply as nothing ends up in the quote box.

Looks like the C3g to 6AK5 adapters have been pulled from eBay as there are none to be found...
Aliexpress has them but they look like the same poorly made product from happydiy998 and most likely are.

They definitely look to be epoxied, if you could pop out that greenish piece of circuit board, you might be able to push the innards out and examine them.


Might get lucky and find out it's only hot glue encasing the insides...

Yes, happydiy988 said he would no longer offer them, in one of his ugly responses to me...

And I have been trying to get the green circuit board out, but so far no luck.

Will keep trying and appreciate ANY help....
post #7940 of 10497

Hi JV,

 

Some time ago I won an item from a Chinese seller for a 1/4 of the going price. The seller did not want to sell the item, stating that he was new to EBay. Called EBay and asked them about the rules. They told me that the seller is obligated to honor the price. After communicating this and mentioning that I would like to leave good feedback, everything was peaches and cream from the seller and no further problems.

 

Suggest that you go to EBay's Resolution Center and find the phone# to contact them. Tell them your story and ask how to proceed.

 

http://res.ebay.com/ws/eBayISAPI.dll?ResolutionCenter

 

If you payed via Pay Pal they may also be able to offer assistance in recovering your money etc. Finally, if you used a credit card, the credit card company may also be able to help you, although foreign purchases are much harder to deal with than domestic.

 

Good luck!

 

This Chinese seller has thousands of items for sale and cannot afford bad publicity/feedback.

post #7941 of 10497
Quote:
Originally Posted by bbmiller View Post
 

Are there any databases which lets you search for tubes by pin arrangement? Do pin arrangements of vacuum tubes have names that can be search for in any way? On the Internet? On a page itself if you search for the recognizable pin arrangement name, say in certain very good datasheets?

 

What "are the to and from tube names" that are iconic for certain pin arrangement conversions adapters which are already made? Are there ones which are important for a little dot IV amplifier which haven't been mentioned on this thread?

 

If there are such databases, I sure don't know about them... But wouldn't that be great!

 

And I am unaware of any names that there might be for the different pin arrangements. I am quite sure that all double triodes using the octal base since about 1940 have the same pin-out, the same as a 6SN7, so that one is easy. There is a small group of 8-pin all-glass miniatures, Rimbase ECC40. These are essentially an all-glass miniature European version of the 6SN7/ECC32. For 9-pin all-glass miniature double triodes, I am aware of 4 different pin-outs: The 6DJ8 pin-out appears to be the most common. And then the 12AU7 pin-out, the 5687 pin-out and finally the 2C51/396A. If there are others, I either can't think of them, or have yet to encounter them.....

 

Among the octals, the 6SN7, of course, and with external heater PS, the 6BL7. 6BX7 and 6AS7.

 

Among the 8-pin all-glass miniatures, Rimlock base tubes, the ECC40, with 0.6A heaters might be worth trying....

 

Among the 6DJ8 pin-out, perhaps the stock LD tubes are the most common.

 

Among the 12AU7 pinout, most are 0.3amps or less, so maybe not many good candidates for power tubes. However, there is the Brimar 13D3, with 0.65A (6.3V) heaters, which might be worth trying. Also, the E80CC, with 0.6A heaters (6.3V)

 

Among the 5687 pinout, in addition to the 5687, there is the 7044 (0.9A) and the 7119/E182CC (0.64A)

 

Among the 2C51/396A, I know only of that one tube, 0.3A heaters, probably not a good candidate.

 

If others have more to add, please do so.....

 

Edit: Added the E80CC


Edited by gibosi - 10/19/14 at 8:19am
post #7942 of 10497
Quote:
Originally Posted by mordy View Post

Hi JV,

Some time ago I won an item from a Chinese seller for a 1/4 of the going price. The seller did not want to sell the item, stating that he was new to EBay. Called EBay and asked them about the rules. They told me that the seller is obligated to honor the price. After communicating this and mentioning that I would like to leave good feedback, everything was peaches and cream from the seller and no further problems.

Suggest that you go to EBay's Resolution Center and find the phone# to contact them. Tell them your story and ask how to proceed.

http://res.ebay.com/ws/eBayISAPI.dll?ResolutionCenter

If you payed via Pay Pal they may also be able to offer assistance in recovering your money etc. Finally, if you used a credit card, the credit card company may also be able to help you, although foreign purchases are much harder to deal with than domestic.

Good luck!

This Chinese seller has thousands of items for sale and cannot afford bad publicity/feedback.

Hello Mordy...

Yes, this Chinese seller is engaging in feedback extortion. Refuses to leave my positive feedback until after I leave him positive feedback.

This is against Ebay policy and I fully intent to report him. He is risking being thrown off Ebay by doing this, so it's a very DUMB move on his part.

I have made some progress on disassembling the socket adapter. I did get the bottom glass pin portion out of the brass barrel. I can see that all 7 pins on the 6AK5 portion had a wire soldered on and done in good fashion. And each went to a connector on the C3g side.

I checked continuity and all sockets (save for one that has no wire connected) on the C3g side DO have continuity to a pin on the 6AK5 side.

So, this means it's wired incorrectly!!!

I will have to sit down and compare the good unit with the bad one to determine where they went wrong.

Will keep folks here informed on what I find...will need to get the C3g side out of the brass barrel next, to be able to fix it....
Edited by JazzVinyl - 10/18/14 at 8:47pm
post #7943 of 10497

Thanks for all that gibosi! That all may take me some time to digest.

post #7944 of 10497
Quote:
Originally Posted by gibosi View Post
 

 

If there are such databases, I sure don't know about them... But wouldn't that be great!

 

And I am unaware of any names that there might be for the different pin arrangements. I am quite sure that all double triodes using the octal base since about 1940 have the same pin-out, the same as a 6SN7, so that one is easy. There is a small group of 8-pin all-glass miniatures, Rimbase ECC40. These are essentially an all-glass miniature European version of the 6SN7/ECC32. For 9-pin all-glass miniature double triodes, I am aware of 4 different pin-outs: The 6DJ8 pin-out appears to be the most common. And then the 12AU7 pin-out, the 5687 pin-out and finally the 2C51/396A. If there are others, I either can't think of them, or have yet to encounter them.....

 

Among the octals, the 6SN7, of course, and with external heater PS, the 6BL7. 6BX7 and 6AS7.

 

Among the 8-pin all-glass miniatures, Rimlock base tubes, the ECC40, with 0.6A heaters might be worth trying....

 

Among the 6DJ8 pin-out, perhaps the stock LD tubes are the most common.

 

Among the 12AU7 pinout, most are 0.3amps or less, so maybe not many good candidates for power tubes. However, there is the Brimar 13D3, with 0.65A heaters, which might be worth trying.

 

Among the 5687 pinout, in addition to the 5687, there is the 7044 (0.9A) and the 7119/E182CC (0.64A)

 

Among the 2C51/396A, I know only of that one tube, 0.3A heaters, probably not a good candidate.

 

If others have more to add, please do so.....

Thanks for this post as I am currently contemplating replacing the 6sn7's due to the distortion yet dont want to fit external heaters for the 6as7's yet. As for the 7044 and 5687's radiomuseum data sheets list them both as 0.45A. is this the case? If so and there are 0.9A versions how do i distinguish the two? thanks.

post #7945 of 10497
Hey, "sgbwill2", Since I'm considering adapting my next LD amp to use 6SN7s, drivers and power tubes, can you share more specifics on distortion you're experiencing? I've heard this mentioned but no specifics. As I wait, I plan to try 6HM5 / 6H30Pi combo..
post #7946 of 10497
Quote:
Originally Posted by Uncle AL View Post

Hey, "sgbwill2", Since I'm considering adapting my next LD amp to use 6SN7s, drivers and power tubes, can you share more specifics on distortion you're experiencing? I've heard this mentioned but no specifics. As I wait, I plan to try 6HM5 / 6H30Pi combo..

When using relatively high impedance headphones such as the sennheiser hd 650 i dont experience any distortion with my LD MK III however when i switch to low impedance headphones such as my dennon 5k's it is un-listenable as the base distorts massively. If your headphone collection solely includes high impedance headphones you should be ok but if you plan on listening to low impedance headphones out of your LD as well i wouldn't recommend it.

post #7947 of 10497
Quote:
Originally Posted by sgbwill2 View Post

When using relatively high impedance headphones such as the sennheiser hd 650 i dont experience any distortion with my LD MK III however when i switch to low impedance headphones such as my dennon 5k's it is un-listenable as the base distorts massively. If your headphone collection solely includes high impedance headphones you should be ok but if you plan on listening to low impedance headphones out of your LD as well i wouldn't recommend it.
Thanks-- I'm almost exclusively using high impedance headphones with my MK IV SE, and using lower impedance headphones (Q701, PX100) with one of three SS amps. I get that the 6SN7s produce richer bass than the 6HM5s, but how are the mids and highs of the 6SN7s, say with HD650s, HD800 or DT880 / 990 cans?
post #7948 of 10497
Quote:
Originally Posted by sgbwill2 View Post
 

Thanks for this post as I am currently contemplating replacing the 6sn7's due to the distortion yet dont want to fit external heaters for the 6as7's yet. As for the 7044 and 5687's radiomuseum data sheets list them both as 0.45A. is this the case? If so and there are 0.9A versions how do i distinguish the two? thanks.

 

These tubes are similar to the 12AU7 in that they can be configured to operate in either a 6.3 volt or 12.6 volt circuit. In 12.6 volt circuits, they draw 0.45A and in 6.3 volt circuits, they draw 0.9A. As the LD employs a 6.3 circuit, these tubes will draw 0.9A. You will need an adapter configured to use them in 6.3 volt circuits:

 

http://www.ebay.com/itm/1x-5687-to-6N6-6N1-6N2-6N6-6N11-ECC88-E88CC-Vacuum-tube-adapter-socket-converter-/321472393335?

post #7949 of 10497
"Rossliew", Appreciated your much earlier WOW! post about near holographic audio from combination of 12AU7 / 6N23P combo with your LD MK III. I'm transitioning through several combinations including 6HM5 / 6H30Pi and possibility 6SN7s. Can you compare 12AU7 / 6N23P combo to 6SN7s in audio quality / soundstage?
post #7950 of 10497
Quote:
Originally Posted by Uncle AL View Post


Thanks-- I'm almost exclusively using high impedance headphones with my MK IV SE, and using lower impedance headphones (Q701, PX100) with one of three SS amps. I get that the 6SN7s produce richer bass than the 6HM5s, but how are the mids and highs of the 6SN7s, say with HD650s, HD800 or DT880 / 990 cans?

 

there are many, many different 6SN7's. Some, like the RCA and Ken-Rad are known for their bass. Others, like the Sylvania are known for their highs. So it will be necessary to roll through a few of these to find the right balance for your ears and gear.

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