I picked up a B1 build from a fellow DIYer, knowing it had a problem (and hoping I could troubleshoot it). It works, but one channel has extremely low output. I can hear the signal coming through, but even at full volume it is barely audible. The other channel works fine. At first I suspected the Alps Blue Velvet pot, so I removed it from the circuit and wired the output wires directly to the board (I want to use it as a buffer only with my passive preamp anyway). That wasn't the problem... I've checked continuity of all the wires, and there are no issues. I've also verified that all grounds are common on the board. No issues. So I checked voltage from the caps (c100/c200 and c101/c201) to ground and they seem read about the same. I also checked all the resistors, and they seem fine. So at this point I'm stumped. I guess my next thought is a bad JFET? But I thought that since the caps read similar voltages the JFETs were probably okay ... but I could be completely wrong bout that. For the record, electronics isn't my strong suit, although I'm trying. I'm not sure how to check for a bad JFET.
Any thoughts or suggestions on what might be wrong or what to check next? My plan, if I can get it working properly, is to take it out of the chassis it's in now and mount the board into a box that matches my passive pre. It will not have a volume pot, and I'll only need one input and one output. A pic of the board that is used is attached (it's a clone B1 board).
Thanks! And I can take pics of anything if needed or if they'll help.
Tom
Any thoughts or suggestions on what might be wrong or what to check next? My plan, if I can get it working properly, is to take it out of the chassis it's in now and mount the board into a box that matches my passive pre. It will not have a volume pot, and I'll only need one input and one output. A pic of the board that is used is attached (it's a clone B1 board).
Thanks! And I can take pics of anything if needed or if they'll help.
Tom
Attachments
The soldering doesn't look too good, I'd start with that. Make sure there's 10VDC bias on the input gate.
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That is an unlicensed PCB and not original Pass Labs.....
Soldering looks pathetic, builder did not understand the connector symbols obviously. Then, after having made the mistake not to use connectors wires have been twisted so sloppy that you can see near shorts. Grounding and input wiring done wrong ...Building like this gives DIY a bad name.
Since it ia s shameless chinese copy I would say support is unwanted.
Soldering looks pathetic, builder did not understand the connector symbols obviously. Then, after having made the mistake not to use connectors wires have been twisted so sloppy that you can see near shorts. Grounding and input wiring done wrong ...Building like this gives DIY a bad name.
Since it ia s shameless chinese copy I would say support is unwanted.
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well put.
Tlarwa,
go and buy a new approved PCB and then we can advise on your new build.
This Forum declares it will not support copyright infringement, but rarely takes action.
Maybe this is the time?
Actually, buying the Pass board and JFET kit from PassDIY and swapping parts is exactly what I was thinking would be the best thing to do. I assume most parts will be usable, and I can always buy the ones that aren't. For the record, I did NOT buy this board originally or build it!
I've been helping Tlarwa troubleshoot this little pre a bit over email and can maybe provide some more second hand details.
The symptom is that the right channel is very weak/low output. The left one sounds like it's working correctly (I haven't heard it personally, but Tlarwa would know if there was an issue as he has played with a lot of gear and knows his own system well).
* The power supply and the 2 x 10k resistor divider (mid point to upper JFET gate) measure correctly.
* The JFET sides of the output caps (10uF) both measure about 8.5VDC.
* The JFET sides of the input caps (1uF) both measure the same DC voltage between channels (maybe Tlarwa can provide the exact measurement).
* Tlarwa removed the input pot so tracking/bad pot can be eliminated.
* touching the lead of the input cap on the JFET side leads to a buzz in the right channel (no effect in the left channel)
I am not a JFET expert, but it sounds to me like the JFETs are biased correctly (or at least consistently between channels). Could they measure consistently between channels but still have a dead (or incorrectly installed) device in the right channel? We've also been discussing the possibility that one of the caps in the right channel is bad, though JFETs are the more fragile device and that's where our suspicions are still focused.
Personally, I think it's important to be sensitive to the fact that this is a board based on a Papa Pass schematic and I agree that making demands of the original designer would be inappropriate. That said, calling it copyright infringement (and the implication that the board is therefore illegal) is inaccurate. That's just not how copyrights work. This misunderstanding potentially does more harm than good in addressing the actual IP issues at stake and helping designers determine how they can/should build value around what they create. If the seller had used Nelson's own schematic images and assembly manual, it would absolutely be a copyright issue, but if the seller had provided Pass-level documentation, we probably wouldn't be troubleshooting in the first place 🙂 Ok, stepping off the soap box...
The symptom is that the right channel is very weak/low output. The left one sounds like it's working correctly (I haven't heard it personally, but Tlarwa would know if there was an issue as he has played with a lot of gear and knows his own system well).
* The power supply and the 2 x 10k resistor divider (mid point to upper JFET gate) measure correctly.
* The JFET sides of the output caps (10uF) both measure about 8.5VDC.
* The JFET sides of the input caps (1uF) both measure the same DC voltage between channels (maybe Tlarwa can provide the exact measurement).
* Tlarwa removed the input pot so tracking/bad pot can be eliminated.
* touching the lead of the input cap on the JFET side leads to a buzz in the right channel (no effect in the left channel)
I am not a JFET expert, but it sounds to me like the JFETs are biased correctly (or at least consistently between channels). Could they measure consistently between channels but still have a dead (or incorrectly installed) device in the right channel? We've also been discussing the possibility that one of the caps in the right channel is bad, though JFETs are the more fragile device and that's where our suspicions are still focused.
Personally, I think it's important to be sensitive to the fact that this is a board based on a Papa Pass schematic and I agree that making demands of the original designer would be inappropriate. That said, calling it copyright infringement (and the implication that the board is therefore illegal) is inaccurate. That's just not how copyrights work. This misunderstanding potentially does more harm than good in addressing the actual IP issues at stake and helping designers determine how they can/should build value around what they create. If the seller had used Nelson's own schematic images and assembly manual, it would absolutely be a copyright issue, but if the seller had provided Pass-level documentation, we probably wouldn't be troubleshooting in the first place 🙂 Ok, stepping off the soap box...
That board is almost a plain copy (volume control pads differ) of the original one which makes the statements, at least morally, true. No misunderstanding here.
The boards even look to be interchangeable. Thanks God I am not a lawyer but using someone else's design and copying the PCB without even asking for permission seems impolite to say the least (whatever the particular law system in the area you live in dictates). This simply is taking without giving.
I think we ought to understand that what is a hobby for many may be a living for some. In this case someone that has a warm friendship with a DIY community and gives away his designs for non commercial purposes which is quite rare if not unique. I am quite sure Mr. Pass does not earn his money from the DIY community, I think it even costs him money. He separated commercial ready built devices from the DIY community but still gives that community a chance to enjoy his designs. He knows most won't be paying customers of his ready built stuff anyway and he probably gets some inspiration and new ideas from his interaction here in return. Original Pass Labs PCBs give the DIYer the opportunity to build a more or less same version of that expensive Pass Labs device he/she can't afford. You get schematics, building tips and support for free and in return you buy the board to compensate a little. That is how it should work, again at least from a moral point of view.
Please note that I am not affiliated with Pass Labs in any way except that I really like the way they deal with DIYers.
The boards even look to be interchangeable. Thanks God I am not a lawyer but using someone else's design and copying the PCB without even asking for permission seems impolite to say the least (whatever the particular law system in the area you live in dictates). This simply is taking without giving.
I think we ought to understand that what is a hobby for many may be a living for some. In this case someone that has a warm friendship with a DIY community and gives away his designs for non commercial purposes which is quite rare if not unique. I am quite sure Mr. Pass does not earn his money from the DIY community, I think it even costs him money. He separated commercial ready built devices from the DIY community but still gives that community a chance to enjoy his designs. He knows most won't be paying customers of his ready built stuff anyway and he probably gets some inspiration and new ideas from his interaction here in return. Original Pass Labs PCBs give the DIYer the opportunity to build a more or less same version of that expensive Pass Labs device he/she can't afford. You get schematics, building tips and support for free and in return you buy the board to compensate a little. That is how it should work, again at least from a moral point of view.
Please note that I am not affiliated with Pass Labs in any way except that I really like the way they deal with DIYers.
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Jean-Paul, copyright protects the expression of an idea, not the idea itself. Legal protection of a process or design such as the B1 would be provided by a patent, not a copyright. A patent must be applied for and granted while a copyright is essentially imbued in a work at the time of publication.
Copyright in this case extends to Pass's documentation and schematic files (or the mountain of support that he is so good to share here on the forum). These are an expression of an idea. But copyright does not cover someone using the same design (idea) to create their own schematic files, manuals, or boards (expression) and resell them. Again, that would need to be covered by a patent.
To be clear, I'm definitely not defending the ethics of cloning another designer's work and selling it without any compensation or reference to the original. But misunderstanding what is and isn't protected by copyright is not a good first step towards everyone making ethical decisions as consumers and/or building (legally defensible) value around an idea as designers.
Edit: I agree with everything you said in your edit. Pass's huge efforts and generosity in the community are exactly the kind of 'value' I'm referring to and I think it's why people are quick to defend him when a clone pops up.
Copyright in this case extends to Pass's documentation and schematic files (or the mountain of support that he is so good to share here on the forum). These are an expression of an idea. But copyright does not cover someone using the same design (idea) to create their own schematic files, manuals, or boards (expression) and resell them. Again, that would need to be covered by a patent.
To be clear, I'm definitely not defending the ethics of cloning another designer's work and selling it without any compensation or reference to the original. But misunderstanding what is and isn't protected by copyright is not a good first step towards everyone making ethical decisions as consumers and/or building (legally defensible) value around an idea as designers.
Edit: I agree with everything you said in your edit. Pass's huge efforts and generosity in the community are exactly the kind of 'value' I'm referring to and I think it's why people are quick to defend him when a clone pops up.
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OK. Your legal system obviously works different (and somewhat bent too) but never mind. I now see why TTIP and CETA were created 😉 One can not apply for a patent for everything one designs is it ? No patent means you're a sitting duck for competitors or worse, copycats ?!? I just noticed seller of that PCB even calls it "Pass B1 clone" which indicates he used the name of the designer, uses the same device name and even admits it is a clone... I think we don't need the law of whatever country to understand it just isn't right for someone to clone a device and sell more of them on Ebay than the original version is sold by the original designer/company. Only thing we can do is buy the right PCB. I leave it to the buyers to decide which PCB is the right one.
Till now I never defended Pass Labs or anyone else in such matters as it mostly concerns DIYers making just 1 copy for themselves but I think I made my point.
Till now I never defended Pass Labs or anyone else in such matters as it mostly concerns DIYers making just 1 copy for themselves but I think I made my point.
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At the risk of running further off course, I appreciate your willingness to discuss civilly and I'll indulge myself in more IP talk.
You can definitely apply for a patent for anything you create here (USA), but there's no guarantee that it will be granted (what's covered needs to be sufficiently unique and innovative). For example, I could apply for a patent on a cathode follower tube buffer using component values that I come up with on my own, but the patent wouldn't be granted because the design wouldn't be sufficiently unique or innovative. Similarly, I'm not sure if the B1 design would qualify for a patent because the JFET follower and current source aren't new concepts (but maybe the combination thereof could be).
And yes, without a patent my cathode follower design could be legally copied by anyone who cared to do so. But they couldn't use my schematic image files or my description of the schematic (which would be covered under copyright).
I'm not sure about using the name Pass B1 clone from a legal standpoint, to be honest. That could be a trademark violation if NP has trademarked "B1" or "Pass" (I think there's an extra complication when enforcing trademark on a name though).
As an aside, I work in publishing and one of our mottos is 'publish or perish.' I think it's in part derived from the very fact that copyright is a loosely defined topic that doesn't grant immutable protection from imitators. One can't rest on one's laurels and allow clones to capitalize on the success of any one book/product.
By the way, did you know that cooking recipes cannot be copyrighted? If you look around for a recipe for a beef roast, you'll find the exact same ingredients in the same proportions listed at dozens of websites and cookbooks. In a way, that's a good analogy for DIY designs (though the recipes are 'free' or paid for through advertising revenue).
You can definitely apply for a patent for anything you create here (USA), but there's no guarantee that it will be granted (what's covered needs to be sufficiently unique and innovative). For example, I could apply for a patent on a cathode follower tube buffer using component values that I come up with on my own, but the patent wouldn't be granted because the design wouldn't be sufficiently unique or innovative. Similarly, I'm not sure if the B1 design would qualify for a patent because the JFET follower and current source aren't new concepts (but maybe the combination thereof could be).
And yes, without a patent my cathode follower design could be legally copied by anyone who cared to do so. But they couldn't use my schematic image files or my description of the schematic (which would be covered under copyright).
I'm not sure about using the name Pass B1 clone from a legal standpoint, to be honest. That could be a trademark violation if NP has trademarked "B1" or "Pass" (I think there's an extra complication when enforcing trademark on a name though).
As an aside, I work in publishing and one of our mottos is 'publish or perish.' I think it's in part derived from the very fact that copyright is a loosely defined topic that doesn't grant immutable protection from imitators. One can't rest on one's laurels and allow clones to capitalize on the success of any one book/product.
By the way, did you know that cooking recipes cannot be copyrighted? If you look around for a recipe for a beef roast, you'll find the exact same ingredients in the same proportions listed at dozens of websites and cookbooks. In a way, that's a good analogy for DIY designs (though the recipes are 'free' or paid for through advertising revenue).
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