Folsom doesn't have a sound card? Something like the Focusrite Scarlett series would be able to give you an idea of what the distortion is. Add a precision oscillator (see "Victor's oscillator") and you'll be able to at least get a spot measurement.
A Scarlett 2i2 would set you back about $200 so you'll have to sell a few more boards. Big deal... Something like the Quant Asylum QA400 would set you back about $400 as I recall. Starting to approach real money, but still not out of reach as a business expense. Just saying. The QA400 is the best audio analyzer I'm aware of aside from the APx500-series from AP (which start at about $6500).
I suggest applying some of this perfectionism to the characterization of the circuit then.
Tom
I take it from this you're currently unaware of Avermetrics which goes for $3k.
Avermetrics - High performance audio analyzer for analog and digital audio products: Amazon.com: Industrial & Scientific
Tom, thank you for the suggestion of the QA400. It could be a purchase this year. It would allow us to take some basic measurements - but it has limitations. Believe me, no one wants us to get the high grade measuring gear more than us!
When I remake the GB, with the new LED first option, battery second, powered feedback I'll try to write more eloquently. But I apologize because there will be some mystery to the circuit. We may not have as many "features" to name off, but I can assure you the subtlety in choices Folsom makes shouldn't be disregarded. Our intent with DIY projects is to offer the kind of stuff we want to own, so we aren't satisfied until it sounds damn good. It's a curated celebration about building your own gear, not involving the whole advanced DIY crowd for circuit design (arguing).
Also, thank you for noticing our project, Tom. We are fans of your work and know you have lots of builders.
When I remake the GB, with the new LED first option, battery second, powered feedback I'll try to write more eloquently. But I apologize because there will be some mystery to the circuit. We may not have as many "features" to name off, but I can assure you the subtlety in choices Folsom makes shouldn't be disregarded. Our intent with DIY projects is to offer the kind of stuff we want to own, so we aren't satisfied until it sounds damn good. It's a curated celebration about building your own gear, not involving the whole advanced DIY crowd for circuit design (arguing).
Also, thank you for noticing our project, Tom. We are fans of your work and know you have lots of builders.
It won't work, a floating LT3045. It would pilfer performance. Believe me, we've been through this trying to brain storm solutions, running LTspice simulations over and over... Our circuit rejects noise very well, and we've checked the cells, they don't produce enough noise to matter. This isn't a matter of being lazy or weird, it's a matter of keeping seriously low memory distortion.
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Oh and I couldn't possibly detail every last system I've heard, swapped gear in, etc... If I have a super power it might be recalling what systems sound like, and being able to pick out particular qualities. It's more like I can make lots of mental notes, than I "hear" the music in my head. One of the biggest things to learn that was so much gear I thought looked dope as hell, and imagined sounded fantastic... didn't. And now it's a personal mission to offer stellar sound to people that can put in the elbow grease, but can't afford big dollar gear - but like in the way that I'm in competition with big names against my DIY projects.
AP will be happy to sell to you. In the meantime, why not use a sound card?
It would also be interesting to see the amount of ripple voltage on the solar cell supply under various amp output conditions (say 20 Hz sine wave, rail to rail, and 10 kHz square wave). I'm curious what the output impedance of those cells are. Fairly high would be my assumption, but it would be nice with measurements ... and you do mention that you have an oscilloscope, so that would be feasible to do.
Tom
Jeremy - I would opt for the green+orange connectors. My dual-mono DIY 7297 never happened (stereo version is still my main unit, along with the Allo stack, displacing the Devialet 400).
I will likely build this one when your revisions + solar integration is ready. Please sign me up for a dual-mono set of boards.
I will likely build this one when your revisions + solar integration is ready
. Please sign me up for a dual-mono set of boards.
Tom, here is the exact solarcell. It should give you all you need about impedance. Better yet if you can measure one better than us... we see no ripple and we are driving the LED with a regulator to control voltage and current (it will never blink, and this circumvents the LED driver).
My laptop sound card is too inferior, and I am currently in possesion of the working amps. We got a real reading of circuit success by measuring for matching with modeling - which a soundcard can't do for us. The proof will be in the pudding... the sound pudding. And it is the kind of pudding you would fill a swimming pool with.
Absolutk, noted!
My laptop sound card is too inferior, and I am currently in possesion of the working amps. We got a real reading of circuit success by measuring for matching with modeling - which a soundcard can't do for us. The proof will be in the pudding... the sound pudding. And it is the kind of pudding you would fill a swimming pool with.
Absolutk, noted!
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"Distortion: I don't have the equipment to check really low distortion, but can tell you it is somewhere 5-100x better than the standard TDA7293. (It does NOT sound like an average chipamp at all)"
I will not jump on this one as I'm seeking HIFI. Sound described as like or better than "tubes". Technology used/described seem to be based on guess work or "hope".
Often distorsion is preferred. But hey, if you like it, you like it
But when one starts to get things together, it's obvious that it is the wrong way.
//
I will not jump on this one as I'm seeking HIFI. Sound described as like or better than "tubes". Technology used/described seem to be based on guess work or "hope".
Often distorsion is preferred. But hey, if you like it, you like it
But when one starts to get things together, it's obvious that it is the wrong way.
//
We have no objection to distortion measurements. But we lack the equipment to do it properly. And we are considering - when we can - buying something that'll give sufficient numbers for people that want to do the project if they can see them, but ultimately is useless for our internal needs (not a good use of our funds for our own needs).
You're also re-contextualizing what I have said. I described it as having a parallel to tubes in that it is easy on the ears, perhaps due to sharing better linearity since there is a character similarity. That has nothing to do with distortion. Do you have any idea how many low distortion tube amps there are? I wasn't talking about a triode-space-heater for my comparison, or the character of distortion for that matter. By the way in-case you don't know, linear distortions are not measured in THD, and they are a focus of this amplifier.
There is no guessing around the circuit or anything to do with it. There isn't a single component or choice made that was a guess. Even when we recommend input capacitors we know what type of a profile each capacitor has for distortion. We know what type of distortion the resistors we use happen to have. We spend hundreds of hours listening so that we can help you make informed decisions on the personal choices involved with building an amplifier. This is all after extensive LTspice modeling, that we're rather proud of because we're very good at it - which was verified with an oscilloscope to our demanding satisfaction.
So out of your whole message the only thing you said was you're going to go seek a project that has a THD measurement because you think that is the answer to subjective quality. That is, while implying I said entirely different things than stated, and that I am some sort of fanboy for distortion. So please do go find another project.
You're also re-contextualizing what I have said. I described it as having a parallel to tubes in that it is easy on the ears, perhaps due to sharing better linearity since there is a character similarity. That has nothing to do with distortion. Do you have any idea how many low distortion tube amps there are? I wasn't talking about a triode-space-heater for my comparison, or the character of distortion for that matter. By the way in-case you don't know, linear distortions are not measured in THD, and they are a focus of this amplifier.
There is no guessing around the circuit or anything to do with it. There isn't a single component or choice made that was a guess. Even when we recommend input capacitors we know what type of a profile each capacitor has for distortion. We know what type of distortion the resistors we use happen to have. We spend hundreds of hours listening so that we can help you make informed decisions on the personal choices involved with building an amplifier. This is all after extensive LTspice modeling, that we're rather proud of because we're very good at it - which was verified with an oscilloscope to our demanding satisfaction.
So out of your whole message the only thing you said was you're going to go seek a project that has a THD measurement because you think that is the answer to subjective quality. That is, while implying I said entirely different things than stated, and that I am some sort of fanboy for distortion. So please do go find another project.
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Now, now... my mom always told me not to get involved in other people's beeswax, and I followed suit. But that was before I realized there's enough love to go around that there should never be friction, especially on an Internet forum!
Every amplifier designer is fighting against the same set of evils before building system synergy. Decades of physics theories are pulled together to fight the same old EMI, RFI, mains noise, build current, reduce heat, adjust impedances and such... each 'designer's' approach is unique. Designer in quotes because at some point the number of variables to tweak are so vast compared to the number of people tweaking it that it approaches art territory.
What Folsom is selling is their philosophy on a circuit board. No pressure to buy into it. You may find that doing a quick 7297 build with their Antipole PSU helps you decide cheaply if you like it enough to invest some time into the bigger project.
I built one of their first amps and paired it with a source from another philosophically aligned company. A sum total of <$500 worth of components ended up displacing >$10,000 worth of gear! It's a great way to keep the hobby alive on the cheap! The downside is I'm left with too many amps
Every amplifier designer is fighting against the same set of evils before building system synergy. Decades of physics theories are pulled together to fight the same old EMI, RFI, mains noise, build current, reduce heat, adjust impedances and such... each 'designer's' approach is unique. Designer in quotes because at some point the number of variables to tweak are so vast compared to the number of people tweaking it that it approaches art territory.
What Folsom is selling is their philosophy on a circuit board. No pressure to buy into it
. You may find that doing a quick 7297 build with their Antipole PSU helps you decide cheaply if you like it enough to invest some time into the bigger project.I built one of their first amps and paired it with a source from another philosophically aligned company. A sum total of <$500 worth of components ended up displacing >$10,000 worth of gear! It's a great way to keep the hobby alive on the cheap! The downside is I'm left with too many amps
Hey guys, here is the PSU board. It uses copper allow terminals. The green ones with clamps are cool but needed too much room and didn't work with the DENO easily.
It allows IEC at the bottom, into the PCB board with filter for AC, and ground isolation w/DENO. Then out the otherside, into the transformer, and back out of the transformer and into rectification and ripple smoothing.
It allows IEC at the bottom, into the PCB board with filter for AC, and ground isolation w/DENO. Then out the otherside, into the transformer, and back out of the transformer and into rectification and ripple smoothing.
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Thanks for the mention!!
I really need to spend a bit more time on these boards... but where will I find the time?
Hi Destroyer OS,
It would be really helpful to show a schematic so we can see what you are doing that is special. I hear error correction and feedback using transistors and solar cells. But haven’t a clue how that’s implemented. Looking around in thread still see no details. If it’s a trade secret you will need to at least show a populated board up and running and some measurements. Anyone with a sound interface and REW can produce nice enough measurements. My 2 cents if you want to see more interest.
It would be really helpful to show a schematic so we can see what you are doing that is special. I hear error correction and feedback using transistors and solar cells. But haven’t a clue how that’s implemented. Looking around in thread still see no details. If it’s a trade secret you will need to at least show a populated board up and running and some measurements. Anyone with a sound interface and REW can produce nice enough measurements. My 2 cents if you want to see more interest.
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