Wow, very nice! Hope to hear some initial impressions soon. The pre-amp should be good to go in just a few hours of operation. Cartridge needs hours and a lot of experimenting to make it work optimally as you might gather from my comments..
I am still waiting for my chassis maker to get back up and running after a summer of disruption and construction (ongoing), so no packaging just yet, the design is not susceptible to anything in my system in close proximity.
I am still waiting for my chassis maker to get back up and running after a summer of disruption and construction (ongoing), so no packaging just yet, the design is not susceptible to anything in my system in close proximity.
Looking good, David!
I am working on mine, too. But I missed some parts and just placed another order. My chassises are from the store here. I think the chassises are ok, workable and nice looking. I also ordered balanced inputs for the future modification.
Although I may finish the SG system, I have to wait to use it because I took my table apart and am waiting for the parts for modifying my table into an air bearing one.
I am working on mine, too. But I missed some parts and just placed another order. My chassises are from the store here. I think the chassises are ok, workable and nice looking. I also ordered balanced inputs for the future modification.
Although I may finish the SG system, I have to wait to use it because I took my table apart and am waiting for the parts for modifying my table into an air bearing one.
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Super, I notice that C2 is rather small, this is a 400V part hopefully? With most cartridges there is going to be more than 100V on that node, the part looks to be the same as C1 which is a 100V part (with about 12V across it +/-). (All other film caps except for C1 should be 400V minimum)
Only one instance of C8 should be installed. Remove one, does not matter which.
Looks good!
Listening to the boards shown below at this very moment.
Only one instance of C8 should be installed. Remove one, does not matter which.
Looks good!
Listening to the boards shown below at this very moment.
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Super, I notice that C2 is rather small, this is a 400V part hopefully? With most cartridges there is going to be more than 100V on that node, the part looks to be the same as C1 which is a 100V part (with about 12V across it +/-). (All other film caps except for C1 should be 400V minimum)
Only one instance of C8 should be installed. Remove one, does not matter which.
Looks good!
Listening to the boards shown below at this very moment.
Kevin,
Both C1 and C2 are 400VDC. I ordered cheap Multicaps for now. If it runs good, I may order nice caps later on.
C8 is kind of big. It is 47uF50V. I kind forced the legs through the holes. I hope I didn't destroy the metal on the wall of holes. Both C12 and C13 are small, 10uF50V. I ordered them from Michael Percy Audio. Why did I order them from Michael Percy Audio in stead of Digikey? I had no idea.
I must have been confused. Here are close up photos of the boards. Please check them for me. Thank you!Jim
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On the audio boards R5 needs to be installed, it's not optional.
On the PSU, I see impending fireworks, glad you asked. The devices on the heat sinks need nylon shoulder washers between them and the stipulated 4-40 machine screws. I believe you have probably shorted the devices directly to the heat sinks which are grounded for safety.
Depending on whether the screws have damaged the heat sinks and/or pads you may need to replace those too. (The devices should be fine.)
I am not a big fan of nylon fasteners but it might be safer for the fets on both boards.
The recommended nylon shoulder washers are posted with the other stuff you asked for.
On the PSU, I see impending fireworks, glad you asked. The devices on the heat sinks need nylon shoulder washers between them and the stipulated 4-40 machine screws. I believe you have probably shorted the devices directly to the heat sinks which are grounded for safety.
Depending on whether the screws have damaged the heat sinks and/or pads you may need to replace those too. (The devices should be fine.)
I am not a big fan of nylon fasteners but it might be safer for the fets on both boards.
The recommended nylon shoulder washers are posted with the other stuff you asked for.
Yes! They absolutely need to be 400V parts.
C4 has about 160V across it except at start up when the full 300V will appear across it. Likely this capacitor will fail over a short period of time.
C5 always has 300V across it, and will fail.
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On both boards, there are some empty slots because I forgot to place order some of parts together. I will order again. I missed R5 and ordered it with some of other parts.
I do have the nylon washers but I didn't know what they are used for.
Ok. I will order new caps, too. And #4 screws.
Thanks!
I do have the nylon washers but I didn't know what they are used for.
Ok. I will order new caps, too. And #4 screws.
Thanks!
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The mute switch if applied to the output will not protect the pre-amp from an open circuit input, a large transient will be generated and there is a possibility of overvoltage on the JFETs.. It is intended to survive "accidents" but no reason to push your luck.
You cannot place the switch at the input because of the bias current, shorting there will also cause a massive shift in DC operating point - no risk of damage to the JFETs but still a huge transient as the operating bias goes completely away.
You cannot place the switch at the input because of the bias current, shorting there will also cause a massive shift in DC operating point - no risk of damage to the JFETs but still a huge transient as the operating bias goes completely away.
Been listening back and forth between the 450c2 and 451 with conical and shibata tips swapped in/out , and the shibata was glued in its housing slightly off , forcing the body to be cocked to get it aligned (lofgren B alignment) with the cantilever , so I,m not yet fully confident its boundaries are met properly.
Waiting for another to get here for a better comparison, but there is a certain purity and ease without irritating you ( no harshness) as things break in and settle down and open up with either for now.
Can,t stand conical tips as they can,t track their way out of a High freq. paper bag, but for wharever reason, I am having no problems with mis tracking at 2.6 grams after about 10 hours disc time . Many piano discs played and maybe 2 hot cut songs were starting to mistrack,
At 2.4 grams, no dice..,
There is a little too much gain (J2-2,3 pins) into a Audible Illusions 3a Aux input. Around 8 o'clock ( Elma stepped attn ) Not necessarily an issue with a stepped attn. , but if someone is using any Alps pot ,they don,t start tracking well until 11 o'clock and up.
Need to check the line dip switches.. or change to the CD input to get more range as it has an inline resistor for hot CD players I believe..
I am not using my linear arm just yet (JVC QL-10/stock arm ) and in comparison to my SOTA vacuum, Spectral Reference LOMC , Stock ET-2 arm ,into Verion transformer, Ai 3a phono stage, it doesn,t quite match just yet in detail , layering and separation, but there certainly is promise and more fiddling to squeeze more out of it. Just needs more effort
Half the fun is getting there and I think the gap will narrow even more.
Watching an FFT plot on all songs and comparing the SG line combo to phono stage , I percieve more separation and dynamic shift with the lomc combo and need more time for comparisons
The road has just begun really and that's makes DIY Worth the effort.
No pain no gain !
More experimentation to come..
Regards
David
Waiting for another to get here for a better comparison, but there is a certain purity and ease without irritating you ( no harshness) as things break in and settle down and open up with either for now.
Can,t stand conical tips as they can,t track their way out of a High freq. paper bag, but for wharever reason, I am having no problems with mis tracking at 2.6 grams after about 10 hours disc time . Many piano discs played and maybe 2 hot cut songs were starting to mistrack,
At 2.4 grams, no dice..,
There is a little too much gain (J2-2,3 pins) into a Audible Illusions 3a Aux input. Around 8 o'clock ( Elma stepped attn ) Not necessarily an issue with a stepped attn. , but if someone is using any Alps pot ,they don,t start tracking well until 11 o'clock and up.
Need to check the line dip switches.. or change to the CD input to get more range as it has an inline resistor for hot CD players I believe..
I am not using my linear arm just yet (JVC QL-10/stock arm ) and in comparison to my SOTA vacuum, Spectral Reference LOMC , Stock ET-2 arm ,into Verion transformer, Ai 3a phono stage, it doesn,t quite match just yet in detail , layering and separation, but there certainly is promise and more fiddling to squeeze more out of it. Just needs more effort
Half the fun is getting there and I think the gap will narrow even more.
Watching an FFT plot on all songs and comparing the SG line combo to phono stage , I percieve more separation and dynamic shift with the lomc combo and need more time for comparisons
The road has just begun really and that's makes DIY Worth the effort.
No pain no gain !
More experimentation to come..
Regards
David
Sounds about right! Place an ugly little blob of that blue tac stuff (various names) available at most ACE hardware stores and Home Depot on the nose of the cartridge. It will do quite a lot in the imaging department, looks ridiculous of course.. Both separation and HF "air" were noticeably improved.
The housing these cartridges are in is really their achilles heal, it's just not very dead and doesn't do the best job of coupling the cartridge, and elements in particular to the arm.
The ugly looking mess I use really does help. This set up in many ways supercedes the performance I am getting with a Windfeld and SPU A95 on the same arm.
The photo shows my current best, which is based on Yamamoto HS-5, 1/8" thick 10gm copper spacer, and 5/32" cocobolo block. This provides the required mass and damping for the cartridge. The cartridge currently in use is a 465C tracking at just north of 4gms with a Panasonic OEM Shibata quad stylus. It's pretty nice. (The cartridge shown is probably the 451C which I think wants a bit less mass than this, with Bliss stylus.)
As an aside I liked the sound a bit better with -25.4V bias so will go back. (Not sure why)
The housing these cartridges are in is really their achilles heal, it's just not very dead and doesn't do the best job of coupling the cartridge, and elements in particular to the arm.
The ugly looking mess I use really does help. This set up in many ways supercedes the performance I am getting with a Windfeld and SPU A95 on the same arm.
The photo shows my current best, which is based on Yamamoto HS-5, 1/8" thick 10gm copper spacer, and 5/32" cocobolo block. This provides the required mass and damping for the cartridge. The cartridge currently in use is a 465C tracking at just north of 4gms with a Panasonic OEM Shibata quad stylus. It's pretty nice. (The cartridge shown is probably the 451C which I think wants a bit less mass than this, with Bliss stylus.)
As an aside I liked the sound a bit better with -25.4V bias so will go back. (Not sure why)
