You'll probably damage the power supply section.
 
You can burn in your 6SN7's using a cheap OTL amp or if you want to use the BA try a cheap pair of PX4's or 300B's.

Here is some info on tube burn-in from Emission Labs.
 

Q:  Do the tubes need a burn in?

 
A:   Yes they do! Good Burn-in will assure maximum lifetime and develop the final sound. These tubes are burned-in initially. This burn-in process will be extended in the first 50 -  100 hours under normal (home) use conditions. This means you must switch off the amplifier after each use, and in the beginning not use the tubes longer than 4 hours at one time. Many short use periods have a better result than few long periods. The tubes need the "cold" periods in between for best formatting of the filament. Some occasional blue glow effects will disappear during burn-in, or may stay. This is not gas, and it is normal. Use different loudness levels from the beginning, and increase the maximum loudness gradually. If tubes with very little use were switched off longer than 12 months, is necessary to repeat the burn in.

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very interesting. thanks.

Hey Guys,
 
since some days I'm a proud owner of an ECBA, starting with basic tubes sold by Craig (EH 300B, TS 6SN7). The ECBA is truly magic, and now I'm planning to get at least some tubes for rolling in the future.
 
I plan to go for one set of excellent tubes, I've heard before the EML 300B Mesh and I liked it quite a lot. Now I'm thinking going for them or their their companion, the EML 300B-XLS. Another option would be to go for the Sophia Electric Royal Princess 300B. I know that it's mainly depending on personal preferences, but probably you could help me to decide which tube to go for. I love to have a great soundstage with precision, but more then anything else I like musicality, which means naturalness. Maybe this helps a bit.
 
Which kind of rectifier tube do you recommend?
 
I'm also looking for some tubes to roll, which are probably interesting sound wise, and not at the high end side of the price. Maybe some of you guys have some good idea and can help me a bit, as I'm fairly new to the tube amplifiers .
 
Some beginners questions, as I learned from trying after switching on I adjust the Voltage level on the power supply to get the power tubes in the audio train (unfortunately Craig was quite short with the operation manual, two pages - or one and a half - is not really comprehensive). To which voltage level I should usually adjust it? Logically it seems to me to adjust the voltage to a fairly low level and then increase the volume (low gain, less resistance in the volume), but maybe I understand it wrong.
 
Thanks in advance!
 
Feuergeist
 
Edit: Someone has some experience with the Takatsuki TA-300B?

As for the output tubes, I can only speak to the EML 300b Mesh plate -- simply fabulous!  
 
When it comes to driver tubes, there are a lot of 6SN7 drivers to choose from.  In my opinion, the two best vintage tubes are Tung-Sol with mica spacer,
 


OR RCA 5692 (AKA 6SN7)

 
There are many other vintage 6SN7 tubes that are very good.  Sylvania, Ken-Rad etc.  You can do your own research at  http://www.audiotubes.com/6sn7.htm  Or read this thread!  I also used adapters with 7N7's and 6F8G tubes, but was not impressed.
 
As for the 6x4 rectifier tubes, the ones that Craig ships are good.  The best upgrade would be 1950's Mullard EZ90's with square getters.  These are rare and hard to find. 
 
Unfortunately it is difficult to find vintage tubes that are truly strong performers.  Most are just worn-out and get recycled.  You need a reliable way to test these for gas, shorts, and emissions.  Most sellers have a return policy but that doesn't keep them from selling duds.  You will be lucky to find 1 in 20 that are truly NOS (New Old Stock) and maybe 1 in 8 that are truly "strong" and about 2 in 3 that are useable.   When I buy vintage tubes from "reputable" vintage tube dealers, I usually find one strong tube along with one week one.  So going the vintage tube route is going to be an adventure and expensive - you have to ask yourself if that's what you want.  There are lots of other ways to spend money on audio that will give you better sound quality.

I found that high quality tubes like the Tung-Sol oval plate w/ Mica that are weak, don't sound as good as a less expensive tubes that are strong.  Unless you can find a tube that has been reliably tested or owned by a friend you  may want to consider just settling on something like a new Psvane Best Quality 6SN7. 
 
(don't screw around with the voltage, set it and forget it - to the right level of course)

The Mesh Plate EML was also fabulous for me … probably I should go for it. I'm only curious if maybe the Sophia Royal sound better … both are a bit too pricy at the same time.
 
Voltage - okay, understood. I'm also not seeking for a voltage mod, but actually I've a lack of understanding - which voltage I'm adjusting? The heater? The Anode of the driver or the power tube? Something else? I'm still a stranger to tubes, and I would like to learn as I love it.


Edit: Okay, Heater voltage.

Congratulations, this is an outstanding amp, it'll give you lots of listening pleasure.
 
The EML are outstanding and so are the KR 300B balloons and PX4.
 
As for the drivers there are so many choices and a lot will depend on your preferences.
 
The Mullard ECC35 pair well with the PX4.
 
The NU, Tung-Sol and Raytheon 6F8G are great too.
 
As for 6SN7 Tung-Sol, RCA and Sylvania are nice.
From the European front RWM, RFT, Philips, Brimar, STC, and MOV B65 are good but expensive.
 
Good Luck!!!!

feuergeist76 said:

  Hey Guys,
 
since some days I'm a proud owner of an ECBA, starting with basic tubes sold by Craig (EH 300B, TS 6SN7). The ECBA is truly magic, and now I'm planning to get at least some tubes for rolling in the future.
 
I plan to go for one set of excellent tubes, I've heard before the EML 300B Mesh and I liked it quite a lot. Now I'm thinking going for them or their their companion, the EML 300B-XLS. Another option would be to go for the Sophia Electric Royal Princess 300B. I know that it's mainly depending on personal preferences, but probably you could help me to decide which tube to go for. I love to have a great soundstage with precision, but more then anything else I like musicality, which means naturalness. Maybe this helps a bit.

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First Thing: Congrats on the ECBA!  Still my favorite amp from what I have had/heard so far...
 
Second: rosgr63 knows his stuff.  If you can get a good pair of KR PX-4 tubes (and your BA has the PX-4/300B switch on the back), that is my favorite pair of tubes.  Best mids to me with my HD800.  
 
BUT:  you have to change the voltage to 4V on the ECBA external power supply.  The 300B tubes run at 5V.  You will burn through your PX-4 tubes faster at 5V.
 
Third: I actually preferred and bought EML 300B Solid Plates over the Mesh Plates for my HD800.  YMMV.  (I did a comparison with both sets in-house over some time before I settled on my choice).  I use them as a different sound from the KR PX-4 and as a back-up set in case anything happens to the PX-4.  If you use different headphones, this can definitely flip towards the Mesh vs. the Solid Plate 300B for some.  I didn't like the mids/treble of the Mesh/HD800 combo though- accentuated the treble peakiness and scoop of the mids for me with the HD800 (FR already shaped that way).  
 
Interesting NOTE: If you do get the EML 300B Mesh Plates for your tastes/phones, you can try running the EML 300B Mesh Plates on the "PX-4" setting (switch on the back of the amp). Craig actually did think that sounded pretty good.  At least different.  He also didn't think that would be bad for the tubes.  (Again, the 300B should be set at 5V on the power supply- regardless of switch on the back of the amp.)
 
Fourth: Be careful purchasing either the KR PX-4 or EML 300B-XLS with the correct base.  The KR PX-4 can come with a UX-4 base or a B4 Base and the EML 300B-XLS comes with the UX-4 base as standard with the Octal base as an option for a special center-tapped configuration (I would recommend checking with Craig if you are going to try one of the EML 300B-XLS tube types).  Most BAs come with UX-4 base sockets and adapters from UX-4 to octal have to be custom-made. I think most KR PX-4 and EML 300B Solid/Mesh Plate tubes come with UX-4 bases.  USA UX-4 & European B4 bases have 4 pins, octal bases have 8 pins.
 
 
EDIT:  Corrected and added some information to the above, plus have some reference pics below...the KR PX-4 can come with a B4 base which would need an adapter to be able to fit in a UX-4 Base.  Probably rare, but my KR PX-4 are B4 base and needed an adapter to be able to go to UX-4 Base.  I didn't mention that because probably rare but people are paying attention to my post, so I share at the risk of making things more confusing.  Looking these up to ensure proper compatibility will hopefully save somebody some hassle.   
 
UX-4 socket (USA & usually on BA) + usually 5V:

 
B4 Socket (European) + usually 4V:

 
 
They even make combo UX-4/B4 sockets:

 
(Got these socket shots from Jac Music, just for reference.)
 
Special version:  EML 300B-XLS  = Octal Base as standard

 
 
 
Here is purrin's thread on modifying the BA to be able to take PX-25 tubes:
http://www.head-fi.org/t/598460/eddie-current-balancing-act-mod-for-px25
 
And here is purrin's B4 to UX-4 adapters, mine were made (as rosgr63's were) by glenn2359.

^ Very nice review of the KR and EML output tubes for the BA.  I've been using the EML 300b Mesh and love them but I'm also tempted to get a pair of KR PX-4.   Does anyone know if the current production KR tubes are the same quality they were a few years ago?  I'd heard the quality may have changed following the death of the founder, but it could just be a nasty rumor . . 

I notice that PX4s have been very expensive lately (at least the Sophias have). Is there a reason for this?

I'd also keep in mind the EML PX4 which are releasing in Feb.

Has anyone used "FullMusic" tubes?
http://www.tonepublications.com/review/tj-music-full-music-vacuum-tubes/

This my actual set up with my BA:
 
KR PX4 power tubes and for different sound flavor, i usually use Tung Sol 6F8G/VT99 or 6SN7 bgrp with my TH900 for clarity/transparency and bass well controlled. In other way, i use mullard ecc35 perfectly matching when i listen with my W3000 headphone.

radio_head said:

  I'd also keep in mind the EML PX4 which are releasing in Feb.

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Oh...this could be good news.  Thanks!!!

Thanks for your good remarks, CEE TEE.

Just one question, I'm about to go for a AVVT PX-4M and im wondering about if the B4 socket is matching the Balancing Act? Because I've read from CEE TEEs post that I should look for a UX-4 socket?

Maybe someone can help me out with that.

Thanks in advance!

Feuergeist