audiophoolery?
I mean , resistors change
It can make a huge difference. And I know this resistor on a ceramic plate can change very much. Thought it made no difference in this circuit. By the way I have heard the circuit with both fases.
In my system, that kind of difference is major, most noticable on LF.
Have listen to different fases. Maybe my Aleph 1.7 does it to. I have shorted one off the fases in. To busy with both pre and power amplifier.
Will not be necessary. Off course there is not such a fault. Different resistors and capacitors have also different sound and silver cables etc.
Hi Guys lots of talk about setiing trim pots at different voltages but just where are people measuring those? I've got no glow at all!! probably better than burning something out assuming I haven't already!!!
I've used crocodile clips to go straight from the DC jack to the board to eliminate anything else as a source of trouble. Is it possible the supplied wall wart doesn't have the guts for the Khozomo swithching board and DC/DC conveter i had to put in to lower the voltage down to 5.5 just for the khozomo board? Iv'e done two ACA with no soldering problems so not looking there just yet.!
I've used crocodile clips to go straight from the DC jack to the board to eliminate anything else as a source of trouble. Is it possible the supplied wall wart doesn't have the guts for the Khozomo swithching board and DC/DC conveter i had to put in to lower the voltage down to 5.5 just for the khozomo board? Iv'e done two ACA with no soldering problems so not looking there just yet.!
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Ok....so when you say "weak bas" it is the "perceived bas" and not something that can be measured?
I have never experienced the "light sound" people think silver gives. For me it is all about "impedance" at the given frequencies. Aluminium would be fine for me as long as the impedance is about the same.
I have never experienced the "light sound" people think silver gives. For me it is all about "impedance" at the given frequencies. Aluminium would be fine for me as long as the impedance is about the same.
Erlend,
Hmm, very odd findings... and playing with voltage would have an effect, more than absolute phase.
Your LF findings sound more like a low frequency filtering to me, regardless what you do. Just thinking loud, but have you calculated your cut off frequency? That is dertermined by the Korg's output cap and the input impedance of your power amp. You want 5Hz or less as real life isn't go or no go but a curve. Of course you might have on top a similar LF filter inside you power amp, and in that case both add up, not even mentioning the LS that might not be really full range in the LF...
Having 2x -1.5dB at 20Hz (filter at the Korg output and another at the poweramp input) is quite noticeable BECAUSE that means -3dB at 20Hz, which wouldn't be itself very relevant on music, but which means if simple filter (best case) still -1dB at 40Hz which can be noticeable with LS cutting already the LF...
Just thinking loud
Claude
Hmm, very odd findings... and playing with voltage would have an effect, more than absolute phase.
Your LF findings sound more like a low frequency filtering to me, regardless what you do. Just thinking loud, but have you calculated your cut off frequency? That is dertermined by the Korg's output cap and the input impedance of your power amp. You want 5Hz or less as real life isn't go or no go but a curve. Of course you might have on top a similar LF filter inside you power amp, and in that case both add up, not even mentioning the LS that might not be really full range in the LF...
Having 2x -1.5dB at 20Hz (filter at the Korg output and another at the poweramp input) is quite noticeable BECAUSE that means -3dB at 20Hz, which wouldn't be itself very relevant on music, but which means if simple filter (best case) still -1dB at 40Hz which can be noticeable with LS cutting already the LF...
Just thinking loud
Claude
Have you taken measurements at the test points (black lead of DVM at ground, red to TP)? Print a copy of the schematic and annotate the voltages as you the them - helps a great deal when trying to find an issue.
What is the power rating of your wall wart? What is the consumption of the khozomo board?
What test point is the question? All i've received is a circuit diagram.
Tha ACA bricks supply enough juice but Korg kit supplied wall wart is 0.4 amp max - which seems very low for anything.
Hikari
Your findings aren't surprising, as said it makes very little difference as Papa did a nice filter. So SMPS convinced me on this application aswell at the end.
Differences are very subtle in my case and more tastes and colours. May I dare to say that the differences you noticed may even be bigger, but just because you created them?
I have selected a SMPS with very low ripple and suited to the task. I am not sure your PS is low ripple where it matters, nor that its overdimensioning is a good thing re efficiency and way it works internaly. In short, in that case, a 10A SMPS might not just be an overkill but could potentialy be a prob for the very low current needs we have, well, who knows...
I am not sure it could make any difference at all in our case, but perhaps worth a try? Have you tried your 6.8uF caps but without the 33000uF ones? Given you have these already and it should be easy, perhaps just for the peace of mind - that is something I haven't tried as I thought not worth but as Extremy Boky said it worked on other applications... and I shall be delighted to read your report on that one as you have started playing with PS!
Thanks for your posts
Claude
Your findings aren't surprising, as said it makes very little difference as Papa did a nice filter. So SMPS convinced me on this application aswell at the end.
Differences are very subtle in my case and more tastes and colours. May I dare to say that the differences you noticed may even be bigger, but just because you created them?
I have selected a SMPS with very low ripple and suited to the task. I am not sure your PS is low ripple where it matters, nor that its overdimensioning is a good thing re efficiency and way it works internaly. In short, in that case, a 10A SMPS might not just be an overkill but could potentialy be a prob for the very low current needs we have, well, who knows...
I am not sure it could make any difference at all in our case, but perhaps worth a try? Have you tried your 6.8uF caps but without the 33000uF ones? Given you have these already and it should be easy, perhaps just for the peace of mind - that is something I haven't tried as I thought not worth but as Extremy Boky said it worked on other applications... and I shall be delighted to read your report on that one as you have started playing with PS!
Thanks for your posts
Claude
Did you read this?: http://www.firstwatt.com/pdf/art_diy_nutube_preamp.pdf The schematic has "T1" thru "T8" I think it is. Those are for checking out voltages. The corresponding points are on the PCB silkscreen - for example T4 is at the zener, and should be 9.1v or thereabouts.
Do you have another higher power wall wart you can try, to see if you have a power supply issue?
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I wouldn't say that was the case, but there is a decent filter before the Korg.
It is my experience that if you are running lots of 2nd harmonic that you will
experience more difference in absolute phase than otherwise.
Of course if the absolute phase were reversed on one channel and not the other,
that would explain everything.
It is my experience that if you are running lots of 2nd harmonic that you will
experience more difference in absolute phase than otherwise.
Of course if the absolute phase were reversed on one channel and not the other,
that would explain everything.
Well the korg board tests just fine but i think I may have fried the Khozomo board at some point - will finish the build with the Alps volume pot and just one source as a temporary measure.
At $200 with remote source selection and volume control the Khozomo board looked like good added value. Will probably bye a nice Elma source switch like the one I put in my valve amp instead!!
At $200 with remote source selection and volume control the Khozomo board looked like good added value. Will probably bye a nice Elma source switch like the one I put in my valve amp instead!!
I have built the kit and and I think the only weakness are the supplied caps. Specially I would like to upgrade the 10 uF caps to Elna Silmic.
The unit which was reviewed by 6moons shows some different choices for the big caps caps. It looks like 2200 uF bypassed by 220 uF of a higher quality and Elna Silmic for the coupling caps? Since it is not going to be a commercial product perhaps Nelson Pass would share some of his thoughts here?
I am wondering whether I would be better off upgrading the 1000 uF caps to bigger values or keep them as 1000 uF and raise the quality to say Elna Silmic all over? I would like to achieve a lower noise floor and improve on the top range if possible.
The unit which was reviewed by 6moons shows some different choices for the big caps caps. It looks like 2200 uF bypassed by 220 uF of a higher quality and Elna Silmic for the coupling caps? Since it is not going to be a commercial product perhaps Nelson Pass would share some of his thoughts here?
I am wondering whether I would be better off upgrading the 1000 uF caps to bigger values or keep them as 1000 uF and raise the quality to say Elna Silmic all over? I would like to achieve a lower noise floor and improve on the top range if possible.
Nelson has commented on 1000 uF vs 2200 uF. 1000 uF was chosen to be sure a small SMPS does not go into current protection and refuse to start.
Regarding the coupling caps it can always be discussed which cap is an upgrade to another. I had several to select from and selected the ones which measured best using a prof. component tester. It was a Nichicon long life 125 C type for use in cars where environment is rough. It works great. I don't believe in special "audio versions" anymore (I did some time ago).
Regarding the coupling caps it can always be discussed which cap is an upgrade to another. I had several to select from and selected the ones which measured best using a prof. component tester. It was a Nichicon long life 125 C type for use in cars where environment is rough. It works great. I don't believe in special "audio versions" anymore (I did some time ago).
I build the B1 korg some time ago.
I did a test connecting the b1 without pot using it as buffer, and with pot alps RK27 100K (from mouser).
It sound much more clear without pot, so my pot degrades sound quality, weird because I did not expect it.
Would a stepped attenuator be a major difference in sound clarity?
I did a test connecting the b1 without pot using it as buffer, and with pot alps RK27 100K (from mouser).
It sound much more clear without pot, so my pot degrades sound quality, weird because I did not expect it.
Would a stepped attenuator be a major difference in sound clarity?