Thanks to you for the detailled feedback, Aljordan!
Following old comparative reviews, the TDK was indeed supposed to be a tad darker than ideal, so your findings seem to confirm it. And that the TOCOS is an excellent top league pot, at a very very affordable price.
So a confirmed best buy IMHO, at least for the 2 of us it seems. I purchased mine a few months ago from the same seller than you and managed to tune it with a simple resistor to make it even better for measurements / channel balance - not that one would really hear the difference though, but values are now in attenuators league for the peace of mind.
Enjoy your Korg B1 very much
Claude
Following old comparative reviews, the TDK was indeed supposed to be a tad darker than ideal, so your findings seem to confirm it. And that the TOCOS is an excellent top league pot, at a very very affordable price.
So a confirmed best buy IMHO, at least for the 2 of us it seems. I purchased mine a few months ago from the same seller than you and managed to tune it with a simple resistor to make it even better for measurements / channel balance - not that one would really hear the difference though, but values are now in attenuators league for the peace of mind.
Enjoy your Korg B1 very much
Claude
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I put the Tocos stereo pot in my valve amp and it was unbalanced by enough so you’d notice. But the same amp had a balance pot (Alps Blue) So correction was possible. Having got problems with an off balance Korg, i’d have been better served by a pair of mono Tocos than the TKD I bought. Nelson’s first Korg design had mono pots and I see the advantage that gives now. If I can’t fix the imbalance I have a new face plate will be required so I can rework the whole facia with one more knob for balance.
I'd like to try add an additional inverting stage to this circuit by adding a unity gain inverting opamp buffer (sacrilege, I know!) but not entirely sure where an appropriate insertion point would be.
I use the circuit as a headphone amp so I can't just swap speaker leads to correct the phase and I'm interested to see if the korg can possibly sound better with correct phase.
Its just an experiment that I'd like to try but a little nudge in the right direction would be appreciated!
I use the circuit as a headphone amp so I can't just swap speaker leads to correct the phase and I'm interested to see if the korg can possibly sound better with correct phase.
Its just an experiment that I'd like to try but a little nudge in the right direction would be appreciated!
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Not an expert but perhaps in front of pot saves you from potential issues such as having another cap in the signal / DC offset or eleminating devices at the output of your "inverting additional circuit", and also from impedance mismatches?
If such things is easily doable, perhaps long term solution could be getting rid of the original first stage and replacing it by an inverting first stage with low output impedance?
Just thinking loud with limited knowledge, I leave it to ZM & Co !
Claude
If such things is easily doable, perhaps long term solution could be getting rid of the original first stage and replacing it by an inverting first stage with low output impedance?
Just thinking loud with limited knowledge, I leave it to ZM & Co !
Claude
Hello happy Diyer's ! (Droopy ...)
Yesterday I received my potentiometer Tocos 2x50k log and I immediately cabled it in my preamp Korg B1 in place of the original Alps blue potentiometer.
This potentiometer really has a very good price / quality ratio: the operation is unctuous and the finish is perfect.
I tested the pairing of the two tracks of this stereo potentiometer and I found a difference of only 2 k Ohms at the first third of the race of it.
For the moment, I have only listened to one recording, but I have not noticed a flagrant balance imbalance.
Here are some pictures of the implementation of this potentiometer :
I shall do other tests later, but although it is difficult to compare before and after the change of this component, it seems to me that, on female voices in particular, a little shine has disappeared. The stereo image also seems to have widened slightly, but this is to be confirmed. I have not noted for the moment a drop in some level of the lowest frequencies ...
Yesterday I received my potentiometer Tocos 2x50k log and I immediately cabled it in my preamp Korg B1 in place of the original Alps blue potentiometer.
This potentiometer really has a very good price / quality ratio: the operation is unctuous and the finish is perfect.
I tested the pairing of the two tracks of this stereo potentiometer and I found a difference of only 2 k Ohms at the first third of the race of it.
For the moment, I have only listened to one recording, but I have not noticed a flagrant balance imbalance.
Here are some pictures of the implementation of this potentiometer :
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
I shall do other tests later, but although it is difficult to compare before and after the change of this component, it seems to me that, on female voices in particular, a little shine has disappeared. The stereo image also seems to have widened slightly, but this is to be confirmed. I have not noted for the moment a drop in some level of the lowest frequencies ...
No genuine from Hi Fi Collective (why they stopped stocking the stereo pots)but the point is they sound good and a pair of mono pot Tocos would be useful for imbalance correction not otherwise possible in current diy Audio kit.
Q Can you buy small balance type trim pots and would you fit after the volume pot internally or could you fit one before final output accessed on the back panel?
"I tested the pairing of the two tracks of this stereo potentiometer and I found a difference of only 2 k Ohms at the first third of the race of it.
For the moment, I have only listened to one recording, but I have not noticed a flagrant balance imbalance."
Hi Gidu,
Would you be interested by posting your measured values?
Of course it is at the end the ratio we are interested in per channel, so not just the resistance value but its value vs the total resistance for a given channel. That ratio is supposed to be the same left and right, but not necessarly the isolated resistance values.
Given values, if it is a small overall ratio shift, that can be addressed easily... that was my case, but again not that I could notice any channel imbalance given the initial channel imbalance was way below that of an Alps blue pot... so normaly "more than enough", in my case far less than 1dB...
I hope this helps
Claude
For the moment, I have only listened to one recording, but I have not noticed a flagrant balance imbalance."
Hi Gidu,
Would you be interested by posting your measured values?
Of course it is at the end the ratio we are interested in per channel, so not just the resistance value but its value vs the total resistance for a given channel. That ratio is supposed to be the same left and right, but not necessarly the isolated resistance values.
Given values, if it is a small overall ratio shift, that can be addressed easily... that was my case, but again not that I could notice any channel imbalance given the initial channel imbalance was way below that of an Alps blue pot... so normaly "more than enough", in my case far less than 1dB...
I hope this helps
Claude
I have used the Jensen JT-11P-1 line transformers with the primaries reversed. They sound very good. Much more money than opamps but very easy to get right.
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I had some hiss after trying to isolate the PCB from the chassis with rubber standoffs. This interrupted the connection between the PCB ground at the mounting holes and the metal chassis. Restoring this link solved my hiss, so I'd recommend checking your grounding.
The way I understand it, you want the signal inversion to take place after the Triode to invert the H2 phase.