Depending on your gerber viewer/editor, you maybe able to add silkscreen and serigraphy or guess you mean soldermask to the existing gerber by creating new layers. I'll give it a try using gerbtool.
Yeah, I can add silkscreen text to the design using gerbtool. It is still a lot of work since you have to basically reverse Eng the layout against the schematic to figure out what is where.
The gerber data reads in as phono19-9.top, .bot, .drd (drill drawing) and excellon drill data as "thruhole". I just created a layer and called it .sst per usually orcad convention.
Lots of fun.
Yeah, I can add silkscreen text to the design using gerbtool. It is still a lot of work since you have to basically reverse Eng the layout against the schematic to figure out what is where.
The gerber data reads in as phono19-9.top, .bot, .drd (drill drawing) and excellon drill data as "thruhole". I just created a layer and called it .sst per usually orcad convention.
Lots of fun.
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I have had mine sitting idle for a few years now as it was working well and then strangely it powers up and the led's light up and then the go off.... only to begin lighting up again etc. with no sound from the cart. During the cycle it picks up radio stations that fade with the led's. One rail seems worse than the other.... scratching my head as to what could be going on?
I loved this thing and just don't have the technical knowledge of the circuit, any pointers would be really appreciated.
Thanks
Greg
I loved this thing and just don't have the technical knowledge of the circuit, any pointers would be really appreciated.
Thanks
Greg
Hei Greg.
Sounds like oscillation or a power supply problem.
First thing you need to use a scope and probe all power rails. If all power rails are ok, short the input to ground and check the amp's output with the scope. After about ten seconds from power on the output should stop swinging and settle down to maybe a few hundered millivolts of subsonic oscillation. If the output does not settle down you need to check that the power supply generates at least 600mA per rail and that the DC-Servo is working properly as well. Report back after this basic check.
Sounds like oscillation or a power supply problem.
First thing you need to use a scope and probe all power rails. If all power rails are ok, short the input to ground and check the amp's output with the scope. After about ten seconds from power on the output should stop swinging and settle down to maybe a few hundered millivolts of subsonic oscillation. If the output does not settle down you need to check that the power supply generates at least 600mA per rail and that the DC-Servo is working properly as well. Report back after this basic check.
Is it the voltage reference LED's in the head amp that fade or the power supply ones?
Sorry guys, I have been so busy of late with my little one starting school that I have just not had time to investigate. I hope to do so over this weekend as I have a new tt arriving (Commonwealth 12d) which has me inspired.
As to your question, yes i think it is the voltage reference LED's. The ones near the input? I will try to upload a video of what is going on.
I'm wishing that I had an electronic's degree about now.
Any help is hugely appreciated.
Thank you in advance.
Greg
Hi Greg.
Check the voltage rail feeding the head-amp, i bet the voltage drops and the amp cannot stabilize. Are you providing enough current to the amp PCB?
The amp will at least 600mA, if i remember correctly, in order to work. I supply it with 750mA to be safe
I will start there and report back. The strange thing is that it was working perfectly for ages, I never turned it off, and then it just started this power cycle. The twin green led's light up and then one side will fade out and then come on again and then the other side will do the same in a continuous cycle of about 3 seconds.
Thanks for your time and help
Thanks for your time and help
Cut Mr. Popa some slack, saying stuff like "half baked" is going against the DIY effort. Mr Popa kindly offered up his designs for all of us, never asked a dime. It was proto type after all. He made himself quiet clear on there is no support for something free. He has no time, he has a family iirc he said on his web site. We know of one user had some chip fail, suspecting it was running pretty hot.
Call it a sort of proof of concept
Being a prototype he did not offer complete cad files. He saved money and had his proto pcbs made with no mask and silk. I kind of support his decision, he does not want people out right stealing his designs and profiting.
I first learned of his phono design effort when I was contemplating building the Denis Colin LP797 design in AudioExpress mag. Mr Popa started with the Denis Colin design mod to the HPS5.1 design which I thought was over kill. I recall Scott W. on diyaudio saying sometime like, that is a lot of for a piece of synthetic diamond scratching some plastic.
Actually nothing wrong with LP797 or HPS 1.0 or 2.0 designs, I'd suggest one of them instead. Could even use ne5534 or cheaper opa to save $ over a AD797.
Call it a sort of proof of concept
Being a prototype he did not offer complete cad files. He saved money and had his proto pcbs made with no mask and silk. I kind of support his decision, he does not want people out right stealing his designs and profiting.
I first learned of his phono design effort when I was contemplating building the Denis Colin LP797 design in AudioExpress mag. Mr Popa started with the Denis Colin design mod to the HPS5.1 design which I thought was over kill. I recall Scott W. on diyaudio saying sometime like, that is a lot of for a piece of synthetic diamond scratching some plastic.
Actually nothing wrong with LP797 or HPS 1.0 or 2.0 designs, I'd suggest one of them instead. Could even use ne5534 or cheaper opa to save $ over a AD797.
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I have been using mine for the past 3 years+, it’s never switched off. Not having had a phono amp of this quality before I cannot comment on its performance compared to other designs, commercial or otherwise. The things I am aware of are its very low noise floor, good headroom (clicks, pops and other vinyl debris are unobtrusive) excellent dynamics and revealing nature; it is clearly a high end device. The measured accuracy of the RIAA filter is, <.1dbs. The cartridges I have used with the amp are Denon 103R, Lyra Delos and Ortofon SPU Silver Mister II
It was my first self-build so I learnt a lot. My comments below may be helpful.
PCB - .I used the designer’s gebbers and cut the board out on a prototype milling machine. I’m confident with soldering SMT parts so the lack of a solder resist was not a problem. I also used 0806 size parts where applicable.
When testing the design, ensure that the power supply you are using can deliver >.8 amps. Until the DC servo stabilises there are high currents circulating in the headamp feedback loop; if this is prevented by limiting the current, the servo will not stabilizes and you may cook the feedback resistors.
When switched on, the servo may never stabilize which will burn out the feedback resistors. This has been discussed earlier in the thread whilst the designer’s response is here. This is one reason why my amp is never switched off.
The 100ohm resistor in the collector of the ZXT790 gets very hot which in turn heats up the adjacent components most notable C225, the 1000uF supply de-coupling cap (I have measured 60-70⁰C). This can’t do much for the life of the component.
The build is not cheap although to buying a commercial product of similar quality would cost a significant amount more; you just need to make a decent case!!
I was never happy with the use of the LM317/377 regulators as designed. There is nothing wrong with them but I felt that the amp deserved better (in my limited experience that is!!). So I removed them and built a pair of pre tracking regulators using the same devices with a capacitor multiplier at the front end. These are separate modules with built in heat sinks. My source of info for the pre tracker’s is from here.
Due to the design not enjoying the same success/interest as the aforementioned Paradise Phono for example, info about it is limited whilst developments of the circuit virtually non–existent. Reading carefully through the build thread will get you a long way though (I missed a couple of important points) and I have attached additional info I found at the time of my build. Further there was a discussion of background relevance in the letters pages of the Linear Audio magazine (Vol.5) between the designer and Brad Wood, see here. This was in response to an article by Ovidiu in an earlier volume. And there is the designer’s web site…..
My own implementation of the design resulted in a two box solution with the Tx, rectifier, smoothing and filter in one and the phono amp, HPF and regulators in the other. I have designed the phono such that it’s a dual mono one, the only common item between channels is the IEC input connector/filter. I built the HPF but find I don’t need to use it. As I was not likely to build many phono amps, I did ‘go to town’ a bit, whether this has improved the SQ, who knows!
Would I build another one? Yes, but I would re-design the PCB to incorporating the HPF, removing the regulators and provide better space around the 100 ohm resistor mentioned above but these are personal preferences. I would also test the suggested improvements mentioned in the attached document and, if favourable, incorporate them; it would be a single channel PCB ie two PCB’s required.
I hope this is of use to you and any other prospective builder.
View attachment HPS 5.1 Info.pdf
Regards,
Preparation is the the largest part if DIY building. If you dont understand the concepts and/or can't find flaw's and faults in the project you build, is DIY then suited for you?
The trick with DIY is to understand what you are creating and what the effect is if you build it the way you do. All efforts to discuss findings and/or improvements are typically well responded to on this forum.
My 2 cents
The trick with DIY is to understand what you are creating and what the effect is if you build it the way you do. All efforts to discuss findings and/or improvements are typically well responded to on this forum.
My 2 cents