Thanks for the kind words nezbleu. No worries for the grumpiness, I fully understand. This was my first PCB build and I went in a little arrogant thinking it would be a cake walk. I paid for not having all the right tools (light and magnifier), but I've learnt my lesson now!
I now have 2 working O2s! Woo! The old transformer that I found in the shed does seem to work, even though it only puts out 12.5 V without a load. (Mains voltage is 230 or 40 here in Germany). I thought that more than 13 V without load was required? Maybe because I'm using low volume it's fine?
For completeness I went out looking for a better transformer. I found and bought this one at the local electronics store.
TRANSFORMER F.LED LIGHT SYSTEM 20 VA | Accessories for outdoor lighting Outdoor Lighting Lighting Home & Garden | Conrad Electronic SE - Accessories for outdoor lighting
It spits out 13.5 V without load and is rated for 1.6 A. I should be able to run both of the amps from this in parallel, no? Neither is going to get near 800 mA. One amp will live on my desk and the other will be on the move, charging at the desk.
Hey,
the data sheets on LED and halogen bulb transformers are usually worthless.
Because the lamps will be damaged or have a reduced lifetime when driven with more than 12V, the transformers usually do NOT output more than 12V.
I have been to a shop that sells and installs lights and measured literally dozens of transformers, none came above 12V without load (so they would not work WITH load for the O2).
Also, I have bought one of the Conrad units that said 13.5V and it delivered 12.5V idle (still not enough for the O2, RocketScientist himself tested it).
That is the only reason I am having the custom transformers built for my GB thread.
They are slightly more expensive than off the shelf units, but are European quality products and come complete with the matching tip for the O2...
(Other members of the first GB thread and I have looked at many alternatives, this is the one that worked best.)
Otherwise you could always run the O2 on rechargeable batteries and swap them out and charge them externally.
More of a hassle, but it works.
Best regards,
Jokener
the data sheets on LED and halogen bulb transformers are usually worthless.
Because the lamps will be damaged or have a reduced lifetime when driven with more than 12V, the transformers usually do NOT output more than 12V.
I have been to a shop that sells and installs lights and measured literally dozens of transformers, none came above 12V without load (so they would not work WITH load for the O2).
Also, I have bought one of the Conrad units that said 13.5V and it delivered 12.5V idle (still not enough for the O2, RocketScientist himself tested it).
That is the only reason I am having the custom transformers built for my GB thread.
They are slightly more expensive than off the shelf units, but are European quality products and come complete with the matching tip for the O2...
(Other members of the first GB thread and I have looked at many alternatives, this is the one that worked best.)
Otherwise you could always run the O2 on rechargeable batteries and swap them out and charge them externally.
More of a hassle, but it works.
Best regards,
Jokener
I have ordered and received the higher-grade and military-grade parts.
But I have not yet assembled the O2's because I didn't have the time.
Once the GB-orders are out the door and things are more quiet, I will get back into hardware-mode.
The fairydust-edition is also close to being ordered, but that is an order for 250€ of components.
(Don't want to order that if I'm not about to build it.)
At least the Ersa i-Con 2C that I ordered will arrive in a couple of weeks.
Then I don't have to work with the pre-war soldering iron anymore and can expect perfect solder-joints.
(Not that you would need an i-Con for that, but I needed to buy something and hate cheap quality, so I tend to go with 'overkill'.)
Best regards,
Jokener
But I have not yet assembled the O2's because I didn't have the time.
Once the GB-orders are out the door and things are more quiet, I will get back into hardware-mode.
The fairydust-edition is also close to being ordered, but that is an order for 250€ of components.
(Don't want to order that if I'm not about to build it.)
At least the Ersa i-Con 2C that I ordered will arrive in a couple of weeks.
Then I don't have to work with the pre-war soldering iron anymore and can expect perfect solder-joints.
(Not that you would need an i-Con for that, but I needed to buy something and hate cheap quality, so I tend to go with 'overkill'.)
Best regards,
Jokener
Hi, the i-Con 2 is a good choice, have one myself and love it! In case you need some additional tips or accessories, solder and so on let me know, I am originally from that little town in Germany where they are produced and will get them with a substancial discount ;-)
Regarding the transformers, I found some reasonably priced ones here that will match the required specs:
Steckernetzteile Wechselstrom AC / AC Adapter - Lüdeke Elekronic Elektronikhandel
made in China though but will do for me, never had any bad experience so far. I asked the shop owner about the voltage without load and requested some datashets if possible - no datasheets but measured voltage is between 1.2 and 2.5 volts higher depending on type and specified load voltage. so the 15V one should be spot on.
You'll find my order in the GB thread
And, big thanks to the RocketScientist for this little jewel!
Regarding the transformers, I found some reasonably priced ones here that will match the required specs:
Steckernetzteile Wechselstrom AC / AC Adapter - Lüdeke Elekronic Elektronikhandel
made in China though but will do for me, never had any bad experience so far. I asked the shop owner about the voltage without load and requested some datashets if possible - no datasheets but measured voltage is between 1.2 and 2.5 volts higher depending on type and specified load voltage. so the 15V one should be spot on.
You'll find my order in the GB thread
And, big thanks to the RocketScientist for this little jewel!
for me, the amp is really versatile, thank you. last time I was planning to make my own PCB and layout from your design before GB was opened. I really like the way how you designed the amp. Here is my contribution:
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An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
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What would be the symptoms of a transformer that isn't delivering enough voltage? So far my old transformer that gives only 12.5 V without load appears to work, although I don't have batteries installed at the moment. In fact the amp is much too loud for me unless I have the pot very low. I intend to change the gain settings. 1x gain requires simply removing the resistors?
I have another question for you guys - one that I asked Rocket Scientist once. I wanted to know whether it will give me clean gain as a preamp for my battery box power WM61a microphone. I need just enough for simple speaker measurements. He suggested that I look at devices from Alesis, Art etc., because he only has tested the O2 to +18 dB. Is it conservative to think that it won't also be reasonable at 20+dB?
I'm more inclined to build another O2 (or use my 2 piggybacked) than buy a mixer, if I can get away with it.
This will be my first headphone amp build and thanks to RocketScientist for all the hard work designing it and also for the all the hard work Jokener has put into the group buy, putting up with not to nice comments as well.
I have a quick question, I will be building some high end wooden enclosures for this HF amp, It’s a new venture, I have several threads on aesthetics in music reproduction equipment scattered around the tinterweb. I’m looking to combine art and music reproduction and see what comes out of the melting pot, like I said it’s a new venture and still in the ideas stage. But if this Amp is anywhere near as good as people have said then I would like to use it in combination with my hand made cases. Of course I will name the HF amp the O2 and will make all the references to your site. But I will have to charge people for them. How do I stand with respect to copy right etc ? I will be marketing them as a handmade case incorporating the O2 rather than just a HF amp.
I have a quick question, I will be building some high end wooden enclosures for this HF amp, It’s a new venture, I have several threads on aesthetics in music reproduction equipment scattered around the tinterweb. I’m looking to combine art and music reproduction and see what comes out of the melting pot, like I said it’s a new venture and still in the ideas stage. But if this Amp is anywhere near as good as people have said then I would like to use it in combination with my hand made cases. Of course I will name the HF amp the O2 and will make all the references to your site. But I will have to charge people for them. How do I stand with respect to copy right etc ? I will be marketing them as a handmade case incorporating the O2 rather than just a HF amp.
According to NwAvGuy's O2 docs, "This work is licensed under a Creative Commons Attribution-NoDerivs 3.0 Unported License." As it stands, that is your contract. You and he may want to hash out details.
Why don't you just sell the handmade cases. I for one just think profiting off an opensource design is harmful to th hobby, RS has done a lot to dispell myths and ripoffs that are prevailent in this hobby and what he altumately is achieving hear is teaching people how to fish rather than giving a fish.
How about selling the cases with customization without the amp, most people that enjoy amp design and building hate case work. A lot of the people who breach the contracts and unethitically profit on someone elses work are the ones posting fancy casework at the other forums, they'll build you a complete O2 with the fancy case for $500 (just not a fan of this). Its why Headwize died and why we don't share designs on any of the forums very often any more.
There is a real demand for a good case guy, especially if you did aluminum and tubes. Also the headamp fad is not a sustainable business model, the money is with well computer integrated DAC's.
I respectfully disagree. A little.
For one, I would also like a separate case. This is where I can agree with you.
I have designed a few myself (for the O2) and will manufacture them this spring.
Afterwards they will be made available for purchase (CNC machined from stainless steel, so price will be north of 50€).
Any 'competition' in this area would be greatly appreciated, because taste differs and there are more than enough customers to support this.
But a well-built O2 in a nice enclosure, maybe complete with a PSU, would be great for many people out there.
If I had not jumped in this head-first, I might still be sitting in front of my pre-war Weller and wonder if I were able to solder it.
Some have offered build-services, so why not offer a complete amplifier?
And if it is openly advertised as an O2-design, I see no problem in asking 1000€ for it.
It would be a problem if it were advertised as 'the next great piece of kit'.
But a Swarovski-covered O2 for $10000 just might be right for someone with bad taste and loads of disposable income
And since Fivetide asked about this so openly, I would be inclined to put him in the 'honest person with a valid interest in earning some money'-category.
-> Ready-built O2 in a nice case for somewhere between 100 and 250€. Depending on the case and build-quality, this is a valid value proposal for many potential buyers.
For one, I would also like a separate case. This is where I can agree with you.
I have designed a few myself (for the O2) and will manufacture them this spring.
Afterwards they will be made available for purchase (CNC machined from stainless steel, so price will be north of 50€).
Any 'competition' in this area would be greatly appreciated, because taste differs and there are more than enough customers to support this.
But a well-built O2 in a nice enclosure, maybe complete with a PSU, would be great for many people out there.
If I had not jumped in this head-first, I might still be sitting in front of my pre-war Weller and wonder if I were able to solder it.
Some have offered build-services, so why not offer a complete amplifier?
And if it is openly advertised as an O2-design, I see no problem in asking 1000€ for it.
It would be a problem if it were advertised as 'the next great piece of kit'.
But a Swarovski-covered O2 for $10000 just might be right for someone with bad taste and loads of disposable income
And since Fivetide asked about this so openly, I would be inclined to put him in the 'honest person with a valid interest in earning some money'-category.
-> Ready-built O2 in a nice case for somewhere between 100 and 250€. Depending on the case and build-quality, this is a valid value proposal for many potential buyers.
I totally agree I would much rather spend the time designing and making the cases, you have no argument from me at all. Quite frankly I don’t really enjoy all the soldering etc or buying the parts and so on. The only caveat I would add is if someone who buys the case also wants the amp fitting or as a complete unit, I would have to consider supplying it. Or the other scenario would be that I make the cases and sell them, and the person who bought it, adds the amp and sells it on for greater profit. Either way my principal focus will be on the case design and creation.
I will be working mainly in metal and wood and experimenting with resins.
@Turbon: Time will tell.
I asked RocketScientist about it and he said it might be a licensing-issue.
-> I would have to open a business, apply for the license (maybe pay for it) and then it is an SMD design, so I would have to have it manufactured in China.
While that is an interesting idea, it was never my plan to become an actual dealer.
My job is somewhere else and I can only make so much profit with this, before it becomes a problem.
(Imagine an engineer at Mercedes or BMW to open a company and earn a second salary off of it. No supervisor would believe it, if you told him it didn't reduce productivity.)
I will most definately offer the ODA (not ODAC) though.
And I'll try to be the first guy with the PCB design and I'll order an express-batch for the early adopters and then a couple hundred boards for those with more time.
(The only difference being a couple €'s in price per board for expedited access to the manufacturing line.)
Also, I will offer the component kits for the ODA as well as enclosures and power supplies.
All of that will happen ASAP as RocketScientist's schedule allows. But we will have to be patient, because in contrast to me, he is not making ANY money in this.
And finally: I might be able to buy a large batch of the ODAC's and offer them at a reduced price.
Or at least as an addition to the ODA so people can order everything through me for their convenience.
I will make the necessary announcements as soon as this happens.
I asked RocketScientist about it and he said it might be a licensing-issue.
-> I would have to open a business, apply for the license (maybe pay for it) and then it is an SMD design, so I would have to have it manufactured in China.
While that is an interesting idea, it was never my plan to become an actual dealer.
My job is somewhere else and I can only make so much profit with this, before it becomes a problem.
(Imagine an engineer at Mercedes or BMW to open a company and earn a second salary off of it. No supervisor would believe it, if you told him it didn't reduce productivity.)
I will most definately offer the ODA (not ODAC) though.
And I'll try to be the first guy with the PCB design and I'll order an express-batch for the early adopters and then a couple hundred boards for those with more time.
(The only difference being a couple €'s in price per board for expedited access to the manufacturing line.)
Also, I will offer the component kits for the ODA as well as enclosures and power supplies.
All of that will happen ASAP as RocketScientist's schedule allows. But we will have to be patient, because in contrast to me, he is not making ANY money in this.
And finally: I might be able to buy a large batch of the ODAC's and offer them at a reduced price.
Or at least as an addition to the ODA so people can order everything through me for their convenience.
I will make the necessary announcements as soon as this happens.
OK, I'll put in an order for 2 ODA's in parts and one of the ready built ODAC's whenever they are available. Starting to have too many well sounding DAC's now.
Brgds
If it is hard to keep everything in mind Jokener, put in a spreadsheet
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I will do my best, though it won’t be mass production each case will be unique and tailored for a specific type of amp or dac etc.
It would be a matter of supply and demand, I will supply the case only without hesitation but if someone wants the full package, as I have said I would have to either outsource the build or make it myself.
Thnaks for that comment I am trying to be open and honest about this .