Just got another reply. => All parts are labled clearly on the board already except for the ladder resistors. They are labled R1, R2, R3 etc and their specific values are listed on that page mentioned.
To me it looks like there is really "minimal" assembly instructions provided because that page lists only the resistor values.
To me it looks like there is really "minimal" assembly instructions provided because that page lists only the resistor values.
Sounds like a project that doesn't really need detailed instructions. Where component values are marked on the board, put that value there. Where it's labeled R1, etc. look it up in the table and put that value in R1. You really only need in depth instructions if there is adjustment and setup required. You can do it.
If you haven't built something from a kit before, it's a good idea to put smaller parts in place first. Mount resistors then caps then relays. Do just a couple parts at a time, install, solder, trim leads before adding more. I always verify part values with a multimeter before installing. Slows me down a bit, but leads to fewer mistakes.
Although it doesn't look like it in the pictures, I'd ask if there are surface mount parts and if so are they preassembled. Surface mount can be tricky. Especially for old eyes and not so steady hands like mine.
Good luck.
If you haven't built something from a kit before, it's a good idea to put smaller parts in place first. Mount resistors then caps then relays. Do just a couple parts at a time, install, solder, trim leads before adding more. I always verify part values with a multimeter before installing. Slows me down a bit, but leads to fewer mistakes.
Although it doesn't look like it in the pictures, I'd ask if there are surface mount parts and if so are they preassembled. Surface mount can be tricky. Especially for old eyes and not so steady hands like mine.
Good luck.
I am just hesitant, because the pictures provided on ebay are not saying much. Other sellers got the same set of pictures too. The problem with the Chinese sellers ist mostly missing information and lack of language skills to get information across. I don't see a processor and the accompanying circuitry (it's not mentioned either), because the back of the control board is not imaged. Schematics would help too. Remote control seems by IR. Interconnects are included. Description is meager.
My soldering skills are OK and I do SMT soldering by hand (hot air and/or soldering iron) for quite some time
already (kits etc. included). That's not the point.
Lack of information is always holding me back if anything.
My soldering skills are OK and I do SMT soldering by hand (hot air and/or soldering iron) for quite some time
already (kits etc. included). That's not the point.Lack of information is always holding me back if anything.
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Hi !
I'm not 100% sure I'm getting you well:
As I have a good +/-15VDC supply (can easily be adjusted from 12 to 17V), I intend to connect it on the J6 power connector.
What is the best option ? 15 V ? 15.5 V ? Less, more ?
Is it OK to keep the Hypex HPR/HNR12 ?
Thanks for your help.
J-M
JMK, your answer was a few posts back. You can keep the Hypex regs if you want. Otherwise you will have to jumper from input to output or just connect your power supply to the regulator output pads and omit the 1000 µF caps.
@J.M.K
I have my PSU set up exactly the same way feeding DC to J6.
In terms of minimizing the heat generated by the Hypex regulators an input voltage of 15.5VDC should be sufficient (minimum stated DC input voltage needed by the Hypex regulators: 15.0VDC), considering the voltage drop across those resistors in front of the 1000uF/25VDC capacitors, because it's already regulated against fluctuations of the mains voltage by the 1st stage regulator. I only added some additional 0.1 uF / 50VDC SMD capacitors in parallel to those electrolyts to filter higher frequency noise coming from the SMPS.
What you got then is a double regulated power supply with the "premium" regulator beeing the second stage. Your 1st stage regulator should be able to handle 1A output current at 15.x VDC for the BPBP.
I have my PSU set up exactly the same way feeding DC to J6.
In terms of minimizing the heat generated by the Hypex regulators an input voltage of 15.5VDC should be sufficient (minimum stated DC input voltage needed by the Hypex regulators: 15.0VDC), considering the voltage drop across those resistors in front of the 1000uF/25VDC capacitors, because it's already regulated against fluctuations of the mains voltage by the 1st stage regulator. I only added some additional 0.1 uF / 50VDC SMD capacitors in parallel to those electrolyts to filter higher frequency noise coming from the SMPS.
What you got then is a double regulated power supply with the "premium" regulator beeing the second stage. Your 1st stage regulator should be able to handle 1A output current at 15.x VDC for the BPBP.
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Thanks a lot to you all.
My 1st stage PSU is supposed to hold 2 x 0.63A, I guess that should be fine.
I'll tell you next week how it's working, my soldering station just passed away, I'll have to wait for the new one a few more days.
JM
I tried that
but the answer I got was: - no schematics avialable
- I should buy the finished product instead of the kit
That doesn't seem to lead nowhere.
Additionally I asked for the type of controller used => no answer and what color those LEDs have => no answer. He is probably just selling that stuff.
I think you're looking for a complete, proven, working solution when none exists (apart from the Hans Polak board)
Please do go and read up on the main thread about the pot and the volume control law.
- the 10k value isn't particularly important; it doesn't particularly define the loading of the previous stage or the drive characteristics for the subsequent stage
- Note that Bruno specifies a linear pot
- so you don't want a logrithmic pot (this kit is almost undoubtedly logarithmic)
- however, a linear pot is specified because of the inherent non-linearities (distortion) of a printed-track logarithmic pot
- the law (volume/vs angle) of the linear pot is dire
- and if you're using switched resistors, then you don't want a linear attenuator either, you don't have the limitations of a printed-track pot, and so you want to create your own law with your own resistor values
Looking at the board, it has 7 relays, so since it gives 128 steps it's behaving in some form of binary way.
What we do need with the BPBP is make before break - don't want the input of the volume opamp to go open circult. We can't tell if the board does that.
So what the board provides you with is
- a bunch of relays
- some form of knob to binary encoder for the relays
- a display for the binary setting of the relays
- and a patch board that lets you have a first stab at mounting the resistors
but the rest is up to you.
You will need to define the resistors to give the law you want, but Hans and AndrewT have already helped in that direction
That's it - a convenient and affordable bag of parts that can probably be evolved into something useful
I'm going to feed my board with +/- 15v DC (or thereabouts) from the SMPSU of a Hypex UCD32 module. Do I need to bypass the rectifiers on the AC input of the board, or will the small voltage drop be within the limits that the regulators can cope with?
It will make the wiring easier if I can go in via the AC input!
It will make the wiring easier if I can go in via the AC input!
Sorry, yet another series of questions about the potentiometer:
I have the slightly unusual requirement of needing only three discrete volume levels, 0dB, -20bB and +20dB.
I was therefore thinking of using a ladder of resistors with the -ve of the LM4562 connected at the point of unity gain.
First question, assuming my resistors all add up to 10k, what proportions would give unity gain? Is it 5k on both sides, or is that too simplistic?
To adjust the gain, without the danger of open circuit and infinite gain, I was going to use relays to short out resistors either side of the fixed point on the ladder, so when in the +20dB or -20dB positions, the total resistance will be less - would it be best to have, say a 20k ladder so that the worst case resistance is around 10k?
Hopefully the image will show what I'm trying to do... will this work?
I have the slightly unusual requirement of needing only three discrete volume levels, 0dB, -20bB and +20dB.
I was therefore thinking of using a ladder of resistors with the -ve of the LM4562 connected at the point of unity gain.
First question, assuming my resistors all add up to 10k, what proportions would give unity gain? Is it 5k on both sides, or is that too simplistic?
To adjust the gain, without the danger of open circuit and infinite gain, I was going to use relays to short out resistors either side of the fixed point on the ladder, so when in the +20dB or -20dB positions, the total resistance will be less - would it be best to have, say a 20k ladder so that the worst case resistance is around 10k?
Hopefully the image will show what I'm trying to do... will this work?
An externally hosted image should be here but it was not working when we last tested it.
20dbswitch by Jem Hayward, on Flickr
Rectifiers, or regulators? - the DC should get through the diodes, I think...
You can either feed DC power to the normal AC power inputs,
or bypass the rectifiers and feed into the output of the rectifiers This also bypasses the first expensive melf filter/current limiter.
or bypass the on board smoothing and feed into the regulator inputs
or bypass everything and feed into the regulator outputs.
4 choices, and the option to link across any part you don't want to populate.
or bypass the rectifiers and feed into the output of the rectifiers This also bypasses the first expensive melf filter/current limiter.
or bypass the on board smoothing and feed into the regulator inputs
or bypass everything and feed into the regulator outputs.
4 choices, and the option to link across any part you don't want to populate.
5k1 before and after would be a good choice that does not load the opamp too heavily while still keeping added noise at an acceptably low level.
Thanks for answering some of my questions.
What do I gather from this:
- a linear stepping is not needed, because we don't have a pot with its idiosyncrasies here but switched metal film resistors. So something semi-logarithmic would be OK, wouldn't it ? It probably is something like it but its not documented...
- its been stated by the seller that he could deliver a 10k input resistance ladder instead of the 50k offered on Ebay
- 7 relays is fine 2^7 eq. 128 steps
- make before break is unknown
- the rest is up to me...
Trying to use someone elses design without documentation (schematics) is a pain, especially if that "someone" is as far away like China and communications at best are sparse etc. I don't want to start tracing boards to find a fault, if not absolutely necessary. If something has to be changed / adapted one is on his own. Some features are not described at all like the processor and what features are supported by the software. If the software is buggy, what to do: unknown up to now. It seems to be switchable between four inputs. Muting: unknown ? LED color: unknown. Supply voltage: 12VDC. Schematics: non-existent. Assembly instructions: mostly non-existent.
I usually don't like to gamble, therefore I try to gather as much information as possible beforehand to get to know what I am up to and if its OK to sink my money into it. This is just for fun on my side thus I don't want to take to many (unneeded) risks. It's a "kit" I know, but that doesn't say to much in terms of building blocks. A lot of experimenting is not planned on my side either...
The word is "probably" or not...
The risk here is, that something not quite usable is been delivered.
What do I gather from this:
- a linear stepping is not needed, because we don't have a pot with its idiosyncrasies here but switched metal film resistors. So something semi-logarithmic would be OK, wouldn't it ? It probably is something like it but its not documented...
- its been stated by the seller that he could deliver a 10k input resistance ladder instead of the 50k offered on Ebay
- 7 relays is fine 2^7 eq. 128 steps
- make before break is unknown
- the rest is up to me...
Trying to use someone elses design without documentation (schematics) is a pain, especially if that "someone" is as far away like China and communications at best are sparse etc. I don't want to start tracing boards to find a fault, if not absolutely necessary. If something has to be changed / adapted one is on his own. Some features are not described at all like the processor and what features are supported by the software. If the software is buggy, what to do: unknown up to now. It seems to be switchable between four inputs. Muting: unknown ? LED color: unknown. Supply voltage: 12VDC. Schematics: non-existent. Assembly instructions: mostly non-existent.
I usually don't like to gamble, therefore I try to gather as much information as possible beforehand to get to know what I am up to and if its OK to sink my money into it. This is just for fun on my side thus I don't want to take to many (unneeded) risks. It's a "kit" I know, but that doesn't say to much in terms of building blocks. A lot of experimenting is not planned on my side either...
The word is "probably" or not...
The risk here is, that something not quite usable is been delivered.
Please, please don't guess at the volume law
- read/search the main thread (created before any of these group buy threads)
- read Bruno's original article
Do this anyway - the idiosyncrasies of the pot have been fully discussed there
- or make yourself a spreadsheet:
for equal changes of angle or %age of pot movement
calculate the values for each part of the pot value
calculate the gain at this angle
plot gain vs pot angle
You could also take Andrew's resistor values (which I linked to in an earlier post) and calculate using those
Decide whether any of the above characteristics will suit your use.
Beware the infinite gain setting! Beware the pot wiper going open circuit! <- these are very important bits that you possibly haven't spotted yet.
No, it's all up to you
(unless I get round to building it first, but don't hold your breath - my first BPBP assembly will simply be with a 10k linear pot to get it working, and that's going to be some weeks off)
Then this volume control option isn't for you and never has been.
Ignore it.
I'll repeat (I've said it lots of times) the volume law of the linear pot is horrible. To quote Bruno from the original pdf (https://www.diyclassd.com/img/upload/doc/an_wp/WP_The_G_word.pdf):
At this stage if you want something risk free you should only be considering Han's solution (or some derivation of it) or Andrew's resistor values. (or a 10k linear pot) They're the only pre-existing documented solutions that I'm aware of
That is what I did first. And discovered that it did not suit what I needed.
The volume law over the middle range of rotation is actually quite good. It's the top 25% and bottom 25% that becomes very high gain or very high attenuation. And as these high ranges are entered the tolerance between the two halves of the lin vol pot become exaggerated for poor balance.
If you only need attenuation and are effectively restricted to using the bottom 50% of rotation and half of that is into the high attenuation range, then you are left with a quarter rotation for your usable range. That's what I could not live with.
Use the stepper to give the operating RANGE that you want and then select the step size to suits what adjustments you would like.
I found the 1.5dB steps to sound almost like it was a continuous attenuation with the steps hardly audible.
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