Korg Forums

Hi
Where did you get the tube balancing programme that you show on the tube replacement tutorial?

when I spoke to Korg tech support they recommended using a special Y-lead mono-to-stereo jack lead to use internal system check for checking the tube balance.

I can post the procedure if anyone wants.

cheers

Sparky

Hey the program is logic, nothing special

It has as a level meter as insert plugin. The procedure you are talking about is indeed the best solution (it is what repair-centers do when they have to replace the tubes and test them). I've heard about it but I'm not sure how it goes.

Grtz

I did see an earlier post mentioning Logic but not being a logic user didn't know whether it was a logic screen shot or some sort of plug-in. I put two new tubes in today and not having the y lead took inspiration from your tutorial and used the phasescope analyser from the Steinberg mastering edition, using a triangle waveform to calibrate the valve attenuators using the mono signal as a reference. Thanks for tip about exchanging tubes. I put in 2 EH 12AX7's and now understand why Ruso is particular about using balanced sets of tubes. Even with the attenuator cranked in opposite directions I'm only just getting a balanced midline.

I've got a copy of the procedure for cold boot calibration which I'll post in this thread and a copy of the wiring diagram for the calibration Y lead. However I don't know how to post a picture on the forum.
Any tips?
sparker

Here are the instructions for tube calibration.
I'm assuming that its OK to put in public domain as these were sent to me to save sending the unit to the service department.
There is a picture and a diagram of the cable that the instructions refer to but I don't know how to paste photo's or diagrams on the forum.

The cable referred to is a balanced (stereo) jack running into a mono (unbalanced) jack. The tip and end ring of the stereo cable are joined together at the mono end tip with the sleeves remaining the same. (I hope that makes sense - ignore my earlier post where I mention a Y cable - it's not).



EMX-1/ESX-1 Tube Calibration
１．Connect the stereo plug of the cable (see fig.) to PHONES and the monaural plug to
INPUT.
2. While pressing ERACE and STEP EDIT, turn the power on. “Valv Wup” is
indicated as stand-by for pre-heating, and also the waiting time is indicated.
Set up the volume knob and switches as follows:
MASTER VOLUME : MAX
TUBE GAIN : MIN
AUDIO IN LEVEL : MAX
MIC/LINE : MIC
3. “Ajst (L)” and a 4 digits figure are indicated in the LCD. If the value is leas than
0010, the test is O.K.. Press the 16 knob at the right bottom. If the value is over it, it is
required to adjust the valve. Adjust the variable resistors which correspond to the
channels referring to the photo below.





4. As well as　“Ajst(L)”, “Ajst (R)” and a 4 digits figure are indicated in the LCD.
If the value is leas than 0010, the test is O.K.. Press the 16 knob at the right bottom. If
the value is over it, it is required to adjust the valve. Adjust the variable resistors
which correspond to the channels referring to the photo above.
5. Once the balance of L/R is automatically adjusted, “ValvGMax GainMx” is
indicated in the LCD. Turn the TUBE GAIN knob to MAX, and press the 16 knob.
6. Check the L/R balance of TUBE GAIN MAX, and return to the normal mode.[/img]

Hi dudes, any of you could tell me if TAD Tubes EF86 / 6267 ('C' Svetlana) are Ok for the EMX?
Maybe too higher gain ´cause it´s pentode instead triode?
It´s seem to be clean and silent... (that site says "special for valve mics like Neuman´s"). I´d love a tube more clean than the included Electro-harmonix... (i mean at least in the lower frecuencies)

Would maybe go better with TAD Tubes 7025 HIGHGRADE?

Thanx in advance

Picked up a couple of the GT tubes on ebay fairly cheaply. What a great mod. Took all of 2 minutes. Much more hifi sounding now.

I've read that GT rebrands the JJs but with stricter quality control.

Hi everyone, this is my first post and I just got an electribe MX. I'm a photographer and I shoot for a high end audiophile company called Music Direct and I talked to one of the tube experts there. He said most tubes at this point are all made by Sovtek to the specifications of each company. I was telling him what I didn't like about the EH tubes that came stock (they distorted in all kinds of wrong ways) and he pointed me to some Tung Sol 12ax7 tubes. Now I have great tight gain. It doesn't really get fuzzy at this point, so it's nice to have a super clean signal from the box and use the tube gain to add low end to the kicks, etc.

I've been reading over the weekend and have learned a lot so thanks everyone for being so generous and sharing experiences. Now to learn how to make this machine do what I'm looking to do (dub, IDM)

Hi,

Just a quick thank-you for the original post

I just (easily) swapped in some new tubes into my EMX-1 and balanced them (using the VU meter in FL studio)..the post made me a bit more confident, and the unit sounds better as a result.

Cheers,
LW.

I just wiggled in a set of jj's. I can turn up the gain and now it adds thickness instead of fizz.

Yeah, isn't it great? I love the way the ECC-803s tubes sound in my EMX-1.

I had good results with Tung-Sol 12AX7 tubes in my MX. The tube gain was originally harsh and choppy @ 30% gain, but now it provides a more clean, harmonic distortion which only starts to get really dirty at around 70% of the way up, although the volume increase is not as pronounced. Overall, these tubes make the sound feel more subtle and "musical" than the standard-issue Electro-Harmonix tubes.

I've got both X units and only use the synth parts of the EMX. The SX still has the stock tubes but I may look at changing these out to see how drums are affected.

Sparker wrote: EMX-1/ESX-1 Tube Calibration
１．Connect the stereo plug of the cable (see fig.) to PHONES and the monaural plug to
INPUT.
2. While pressing ERACE and STEP EDIT, turn the power on. “Valv Wup” is
indicated as stand-by for pre-heating, and also the waiting time is indicated.
Set up the volume knob and switches as follows:
MASTER VOLUME : MAX
TUBE GAIN : MIN
AUDIO IN LEVEL : MAX
MIC/LINE : MIC
3. “Ajst (L)” and a 4 digits figure are indicated in the LCD. If the value is leas than
0010, the test is O.K.. Press the 16 knob at the right bottom. If the value is over it, it is
required to adjust the valve. Adjust the variable resistors which correspond to the
channels referring to the photo below.

4. As well as　“Ajst(L)”, “Ajst (R)” and a 4 digits figure are indicated in the LCD.
If the value is leas than 0010, the test is O.K.. Press the 16 knob at the right bottom. If
the value is over it, it is required to adjust the valve. Adjust the variable resistors
which correspond to the channels referring to the photo above.
5. Once the balance of L/R is automatically adjusted, “ValvGMax GainMx” is
indicated in the LCD. Turn the TUBE GAIN knob to MAX, and press the 16 knob.
6. Check the L/R balance of TUBE GAIN MAX, and return to the normal mode.[/img]

i Try to follow those instruction for the calibration but the instruction is incomplete.
My “Ajst (L)” value is 0999 so i try to ajust with the variable resistor but value did not change at all.
pussing on button [16] changed nothing. but the bar change buttons [ < ] [ > ] permit to navigate in the different options
“Ajst (L)”“Ajst (R)” “ValvGMax GainMx” etc... there was also a step where all the led's on the ESX where blinkink leaving me in a questionable state! :-/

i just put the cover back on without any further calibration (later, when i get more detailed information)
before: '12AX7 EH' now 'JJ ECC83 S'
BIG difference! less gain/distortion & really more punch & warmth.

If anybody can make a videotutorial on every steps of the calibration or a more complete instructions, i will give him a hug!

UPDATE:
a bad wire (stereo to mono) was maybe the cause of the strange value (0999)
I will retry the calibration this evening.
again, if anyboby have done this before please detail all the steps for a perfect calibration please.

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