Looking at the original connection of the individual GNDs of the VoICB, they are right at the GND plane, distance my be 1 mm. It has been suggested to drill 0.8 mm (?) holes through the PCB near those net ties and have them connected to the GND plane at the back of the PCB. The question then is if "my" other arrangement is *truly* noticeable, because we are probably already way beyond the limits of human perception. Nobody really seems to have tested or verified this at least to my knowledge...
I am using SPS power modules instead of a linear PS, because the filter network in front of the Hypex regulators plus some larger MLCC capacitors in parallel are taming already HF noise from this side and looking at the oscilloscopes display (1mV) I couldn't detect any visible noise difference (BW 20 MHz) behind the Hypex regulators between feeding the BPBP by a rather expensive linear laboratory PS (BKPrecision) and by those SPS modules.
The cabinet construction should be adequate though hindering HF radiation entering the analogue portion.
I am using SPS power modules instead of a linear PS, because the filter network in front of the Hypex regulators plus some larger MLCC capacitors in parallel are taming already HF noise from this side and looking at the oscilloscopes display (1mV) I couldn't detect any visible noise difference (BW 20 MHz) behind the Hypex regulators between feeding the BPBP by a rather expensive linear laboratory PS (BKPrecision) and by those SPS modules.
The cabinet construction should be adequate though hindering HF radiation entering the analogue portion.
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Unfortunately the bluetooth module's onboard antenna is at the lower edge of that small bluetooth PCB about the same height position as the lower mounting holes of the Maya the control board. If you mount this onto a metal front panel with a cut-out for the display and IR controller then the antenna is always behind the metal portion of the front panel due to that offset. Wouldn't it be better to have that bluetooth module mounted differently such that the BT antenna would be in the open and behind the sideways extended cut-out ?
Hello Bao,
I have no clue how that message is displayed ...
Can you please write latest OLED firmware from here http://www.diyaudio.com/forums/analog-line-level/291226-remote-control-bpbp-23.html#post5066028 ?
Regards,
Tibi
Oooops, had the Maya control board upside down. Thus it's the "upper" and not the "lower" mounting holes I am referring to...
Thank you
Hello Tibi, once I receive the programmer, I will update the software. I was able to get it to start normally but was unable to get it to work with the BPBP. I'm not sure if it's the Maya or the VolCB board. I also was not able to recognize the Maya via Bluetooth. I know the BPBP works beautifully with just the standard linear pot. I will update you once I install the latest software.
Bao
Hello Tibi, once I receive the programmer, I will update the software. I was able to get it to start normally but was unable to get it to work with the BPBP. I'm not sure if it's the Maya or the VolCB board. I also was not able to recognize the Maya via Bluetooth. I know the BPBP works beautifully with just the standard linear pot. I will update you once I install the latest software.
Bao
Hi Tibi.
For a smoother feel, should it be needed, for the rotary encoder, I was thinking of getting a Bourns encoder in the future (as used in my Audio Synthesis DAX Decade - very nice feel). What specs would I need to replace the one that comes with the Maya? 64 pulse? what else?
I would also like to use a rotary control for select, continuous turning of a knob to replicate continuous pressing of the select button. Has anyone done this and how would one go about it? Is there a select downwards/backwards option? Maybe the maya control counts the momentary select switch as a pulse and so a simple incremental encoder is all that is needed, perhaps even the same as the one supplied?
For a smoother feel, should it be needed, for the rotary encoder, I was thinking of getting a Bourns encoder in the future (as used in my Audio Synthesis DAX Decade - very nice feel). What specs would I need to replace the one that comes with the Maya? 64 pulse? what else?
I would also like to use a rotary control for select, continuous turning of a knob to replicate continuous pressing of the select button. Has anyone done this and how would one go about it? Is there a select downwards/backwards option? Maybe the maya control counts the momentary select switch as a pulse and so a simple incremental encoder is all that is needed, perhaps even the same as the one supplied?
Hello Tibi,
Pretty satisfied with the preamp. Do you have news of a new version of the firmware ?
I still use a power switch for my unit, and i find it annoying that the controller auto standby at power on. An option to disable this auto standby would be really appreciate.
Another great option would be able to set the default attenuation (per channel would be even greater). Right now i need to raise the volume from 7bd at every start up.
Regards
Pretty satisfied with the preamp. Do you have news of a new version of the firmware ?
I still use a power switch for my unit, and i find it annoying that the controller auto standby at power on. An option to disable this auto standby would be really appreciate.
Another great option would be able to set the default attenuation (per channel would be even greater). Right now i need to raise the volume from 7bd at every start up.
Regards
Normal operation is to use stand-by and this will also preserve volume per channel.
However, your request was noted and will be implemented in a future update.
Brgds,
Tibi
Today you may buy one Maya for BPBP with OLED display and IOS or Android at a little discount.
VoICB pcb board with 2 channels is included.
Power relay board is included.
OLED display green or blue. Please mention in paypal order.
Regards,
Tibi
VoICB pcb board with 2 channels is included.
Power relay board is included.
OLED display green or blue. Please mention in paypal order.
Regards,
Tibi
hi Tibi,
I am not sure where is the latest version of the Firmware for Maya with VoICB for BPBP with ... I saw comment that 1.4 is only for regular Maya (6 inputs etc) but not sure which one is for Maya for BPBP which i have and where to download it.
The one from your website is 1.4 but seems not to be for BPBP.
In this thread there is 6 months old "maya_v_1_3_h_rays_oled_bpp_ninp.zip" (i have OLED screen) but that is 1.3
Could you post the link please ?
thank you !
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Great thanks
1 how do i order nee BT modele ?
2 where’d to download latest firmware for vicol to improve ClickiNg sound when increasing volume I have oled version
Thank you !
Relay attenuator crosstalk
Has anyone using the relay attenuator measured crosstalk with good measurement kit? I see slight issues in my implementation.
What I have done is combine Bruno's preamp and Hans's relay attenuator and chuck in a microcontroller circuit, see schematics attached. Everything works fine, it has been in use since last summer. It is very quiet, noise level is somewhere around -114dBV with 0 dB max gain.
However, crosstalk is not as good as it should be. At 0 dB when all relays are on it is superb at around -130 dB at 10 kHz BUT when I take volume down even 1 dB, crosstalk tanks to -95 dB. At first I blamed the relays but then thought it must be my layout as xtalk is so good when all relays are on. But after some investigation I do think it is the relays. When they are on, it is all low-impedance path through the relays but when one is off, there is higher impedance contact hanging about that seems to pick up the signal from the other channel.
Of course this does not have any practical meaning but as the goal in this was to make superb (also in terms of measurements) preamp, this does bother me. However, fixing would mean complete re-design with separate relays for each channel.
I will try to confirm my findings at work with audio analyser next week.
PS. If you wonder where are the attenuator relays on photos, they are on bottom side - I screwed up the layout
First time I used relays that have polarity so did not even see it...
Has anyone using the relay attenuator measured crosstalk with good measurement kit? I see slight issues in my implementation.
What I have done is combine Bruno's preamp and Hans's relay attenuator and chuck in a microcontroller circuit, see schematics attached. Everything works fine, it has been in use since last summer. It is very quiet, noise level is somewhere around -114dBV with 0 dB max gain.
However, crosstalk is not as good as it should be. At 0 dB when all relays are on it is superb at around -130 dB at 10 kHz BUT when I take volume down even 1 dB, crosstalk tanks to -95 dB. At first I blamed the relays but then thought it must be my layout as xtalk is so good when all relays are on. But after some investigation I do think it is the relays. When they are on, it is all low-impedance path through the relays but when one is off, there is higher impedance contact hanging about that seems to pick up the signal from the other channel.
Of course this does not have any practical meaning but as the goal in this was to make superb (also in terms of measurements) preamp, this does bother me. However, fixing would mean complete re-design with separate relays for each channel.
I will try to confirm my findings at work with audio analyser next week.
PS. If you wonder where are the attenuator relays on photos, they are on bottom side - I screwed up the layout
First time I used relays that have polarity so did not even see it...Attachments
Nihtila,
Let me first say how impressed I am by your “all in one” design.
At first sight you seem to have implemented everything perfectly.
The difference between all relays on and all other settings is not just a matter of impedance, but in all other settings you are using the extra line gndr and gndl.
So when these lines are capacitively picking up signal from the other channel this may also cause crosstalk going down.
When however your suspicion is right, the more attenuation, the higher the impedance and the further crosstalk should go down, is it ?
The other question is, is the crosstalk from R-L the same as from L-R ?
At this very moment I don’t have the time to measure crosstalk with my preamp, but after next week that’s no problem unless somebody else can do it on shorter notice.
Hans
Let me first say how impressed I am by your “all in one” design.
At first sight you seem to have implemented everything perfectly.
The difference between all relays on and all other settings is not just a matter of impedance, but in all other settings you are using the extra line gndr and gndl.
So when these lines are capacitively picking up signal from the other channel this may also cause crosstalk going down.
When however your suspicion is right, the more attenuation, the higher the impedance and the further crosstalk should go down, is it ?
The other question is, is the crosstalk from R-L the same as from L-R ?
At this very moment I don’t have the time to measure crosstalk with my preamp, but after next week that’s no problem unless somebody else can do it on shorter notice.
Hans
Thank you for your kind words Hans!
Those long GNDL and GNDR reference traces were indeed my first suspicions as that is the difference in the circuit when one or more relays are off. I still cannot say 100% sure they are not the reason for this increased crosstalk but there is quite some clearance on board and in fact I have not seen this bad crosstalk in any of my boards. This is by no means optimal layout but should not be my worst either. Unless I am totally blind to something which is possible.
Crosstalk changes between -85 and -95 depending on relay settings, except -130 when all on. But I have not been able to see clear pattern how it changes. I was also expecting that. But then again, if it is a combination of the impedance at certain point and the rest of the division network it can be more complex.. at least it is complex trying to think how it goes
Crosstalk is practically identical L->R and R->L. This is also one reason why I thought it would not be the GNDL and GNDR traces based on how they go on PCB.
I just prepared one board with all attenuation resistors and opamps around, nothing else. Then shorted relay contacts in "all on" position. I will measure crosstalk, then change one short on "off" position and see what happens. So basically replace relays with shorts. I just don't have audio measurement kit at home so it is a bit slow to debug. But I have access to AP at work so shouldn't complain too much.
But if someone has good enough kit, would be interesting to hear crosstalk measurements in different layout.
New MAYA BPBP version 1.5 with IOS support has been released.
Thanks to Hanswolek we have now a final version for IOS, fully tested and with several nice improvements, like display on/off from menu and remote, more clear menus and a number of long standing bugs finally cleared.
Please note that in order to use MAYA BPBP with an iPhone you need a BLE module. This can be purchased from us.
Latest MAYA BPBP Android firmware can be downloaded from here
Latest MAYA BPBP IOS firmware can be downloaded from here
Download MAYA remote control for IOS from App Store
More information on vicol audio : MAYA - world best stepped volume attenuator
Regards,
Tibi
Thanks to Hanswolek we have now a final version for IOS, fully tested and with several nice improvements, like display on/off from menu and remote, more clear menus and a number of long standing bugs finally cleared.
Please note that in order to use MAYA BPBP with an iPhone you need a BLE module. This can be purchased from us.
Latest MAYA BPBP Android firmware can be downloaded from here
Latest MAYA BPBP IOS firmware can be downloaded from here
Download MAYA remote control for IOS from App Store
More information on vicol audio : MAYA - world best stepped volume attenuator
Regards,
Tibi
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