[Kryl0071]

Do it ASAP and after you will done, you will need to burn up 1502 for about 48-72 hours with music on.

 

[stolikat]

Well I just have to say that the tubes that come with this amp are not bad at all. They are made by Shuguang and the 12ax7 actually gets good reviews. It is definitely harder hitting on the low end than my 12au7 RCA clear top. I clearly have no point of reference with regards to the 6v6's as I have yet to order any. I keep going back and forth between those two tubes and the more I burn in the Shuguang the more I am liking it.
 
Update. I just went back to my indeed G3. These power tubes are definitely holding back the sound stage presence.

 

[stolikat]

Sad to see that this thread has gone dead even though massdrop keeps selling this amp. I just grabbed some JJ Tesla 6V6's and this sweet Sylvania 12ax7. Cant wait!

 

[1800yolk]

  Great, I'll manage somehow with the installation, thanks!
i see you have the X2's, can you clearly hear a difference between the tube and a solid state on them?

from your comments it appears you have never done electronics work like this? if this is the case, I would recommend you find someone who already has, since you wouldn't want to goof up your motherboard. Also, working with capacitors is dangerous because they need to be grounded first, and I'm unaware of how long it takes to slowly ground itself when left unplugged for a period of time. If you do try grounding them, electrically insulated gloves might be a good thing to have. Possibly a tad overkill given the size of the capacitors, but still not a bad idea.

 

[alexandertm8]

...  
I've collected up a few 12SN7GTs from various sources. The 12SN7 is the same as the famous 6SN7 except for the heater voltage, and since there are fewer applications for the 12V tubes, they tend to be cheaper. A 12SN7 to 12AU7 adapter is needed, but I'm stoked to say the 12SN7GT works in the APPJ!
 
...

Did you do any modification in the circuit or just plug-n-play?
I can't locate any of the famous 12sn7gt Tung-Sols in Europe and I'm reading that the rest 12sn7 aren't any good, do you have a opinion on that matter? Would you trust/place a 12sn7gt/a JAN General Electric on the appj?

 

[AzraelDarkangel]

  I have to give them another listen since I haven't in a while. What I do remember is the soundstage is massive, but some mid or mid-lows sounded distant, almost like they were being played farther away than the rest of the music (recessed I think is the correct term?). The preamp tube probably has an effect on this too- IIRC I was using the 8416 most of the time and another type of tube may compensate for this. SECOND EDIT: May have been the recording? I listened with the 8416 and a GE black plate 5751 and didn't get that recessed feeling on some mids I thought I had heard.
 
Physically, the T-S KT66s are very wide- you can't use 12SN7-types in the preamp socket as the KT66s will foul against the 12SN7's base.
 
EDIT: Here's a picture.
 
 

 
There is something mildly erotic about such a cute little amp with such massive tubes....or I might just have an issue.

 

[CZ4A]

Did you do any modification in the circuit or just plug-n-play?

I can't locate any of the famous 12sn7gt Tung-Sols in Europe and I'm reading that the rest 12sn7 aren't any good, do you have a opinion on that matter? Would you trust/place a 12sn7gt/a JAN General Electric on the appj?

No circuit modifications required, just the adapter.

12SN7s are identical to their 6SN7 equivalents except for the heater voltage and current draw. That GE 12SN7GTA you mention should have the same sonic qualities as a GE 6SN7GTA, a Sylvania "Bad Boy" 12SN7 will sound like a "Bad Boy" 6SN7, etc. My Tung-Sol round plate 6SN7 and 12SN7 definitely sound similar given they are used in two different amps (Sunrise III and APPJ).

Will the GE work? With the correct adapter, sure. Will it sound good? I don't know. I've never listened to a GE 6/12SN7 but Googling reviews for the 6SN7GTA should bring up something.

 

[alexandertm8]

No circuit modifications required, just the adapter.

...

Will the GE work? With the correct adapter, sure. Will it sound good? I don't know. I've never listened to a GE 6/12SN7 but Googling reviews for the 6SN7GTA should bring up something.

Thanks for the reply! What kind of adapter should I be looking for? I 've found a few 12SN7 to 12AU7 on ebay but the specify "...Cautions: Do not use 12V adapter on 6V circuit!".

 

[CZ4A]

Thanks for the reply! What kind of adapter should I be looking for? I 've found a few 12SN7 to 12AU7 on ebay but the specify "...Cautions: Do not use 12V adapter on 6V circuit!".

This is the adapter I have:

http://www.ebay.com/itm/1pc-12SN7-12SL7-TO-12AU7-12AX7-tube-adapter-for-you-amp-12-6V-heat-/200943948306

Remember, the preamp (12AX7/6N4-P) tube runs on a 12V circuit, while the power tubes (6V6GT/6P6P) tubes run on a 6V circuit.

 

[Zulkr9]

Just wondering if the transformers are modified can it handle KT88/KT66 the ones with the 1.3A heater current ? 

 

[alexandertm8]

Just received mine, left channel dead. Pretty disappointing, was expecting it with high hopes. Low volume output too!

P.S. Its a bad tube, already order another couple.

 

[Josh-Fi]

No circuit modifications required, just the adapter.

12SN7s are identical to their 6SN7 equivalents except for the heater voltage and current draw. That GE 12SN7GTA you mention should have the same sonic qualities as a GE 6SN7GTA, a Sylvania "Bad Boy" 12SN7 will sound like a "Bad Boy" 6SN7, etc. My Tung-Sol round plate 6SN7 and 12SN7 definitely sound similar given they are used in two different amps (Sunrise III and APPJ).

Will the GE work? With the correct adapter, sure. Will it sound good? I don't know. I've never listened to a GE 6/12SN7 but Googling reviews for the 6SN7GTA should bring up something.

Hey you mentioned early in the thread that you'd compare the sound quality with the Sunrise. Can you give an honest comparison please? I wonder how the otl mosfet output compares to the transformers of the appj

I'd assume the transfoemer would have more purity to the sound instead of a high frequency switcher.

 

[kazcou]

I ordered this converter on ebay (6SN7 > 12AX7 12,6V)
http://www.ebay.com/itm/1pcs-6SN7-Replace-12AU7-Tube-Amplifier-Socket-Adapter-12-6V-Suzier-A4/281951474478?_trksid=p2054502.c100229.m3211&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20140505115423%26meid%3Db0c9127746164f709a59239de1f4eadd%26pid%3D100229%26rk%3D1%26rkt%3D15%26sd%3D281951474478
 
hope it will work and not kill the tube or the amp

 

[Saillaw]

  Okay i think i got it now:
 

right?
 
How do you connect them? do you need a welding machine for this? or you just unplug the old one's and plug the new one's?
sorry for all the questions, it's not my strong suit..

 
Hello RoyT,
 
Did you ever give this a try?   I'm curious about the removal/installation difficulty, how did it go?  I'm not the best at small soldering, but have a neighbor who is a wiz I can bribe to help if the sound is improved enough to merit the effort?

 

[CZ4A]

I ordered this converter on ebay (6SN7 > 12AX7 12,6V)
http://www.ebay.com/itm/1pcs-6SN7-Replace-12AU7-Tube-Amplifier-Socket-Adapter-12-6V-Suzier-A4/281951474478?_trksid=p2054502.c100229.m3211&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20140505115423%26meid%3Db0c9127746164f709a59239de1f4eadd%26pid%3D100229%26rk%3D1%26rkt%3D15%26sd%3D281951474478

hope it will work and not kill the tube or the amp

Interesting. I didn't know there was a 6SN7 to 12AX7 adapter that runs on 12.6V. That would open things up immensely for tube options because now you can run 6SN7s and any other types that could be adapted to work in a 6SN7 circuit.

Hey you mentioned early in the thread that you'd compare the sound quality with the Sunrise. Can you give an honest comparison please? I wonder how the otl mosfet output compares to the transformers of the appj

I'd assume the transfoemer would have more purity to the sound instead of a high frequency switcher.

My Sunrise is at work. I will try to bring it home on a open weekend and do a back-to-back comparison.