Alex, congrats for "new" cart and new job. Good luck and let us know how the cart went again on FSP. Please post one picture of your build for Chris to see it also (as he joined late in this thread) when you will be having some spare time.
Arrrrghhh. And all that just to cause you noise and pain searching for the source of it! So glad it got repaired. Yes, please, post pics of your build.
I am trying to use your figures to predict the maximum output from the RIAA pre.
3mV is the specification for a 5cm/s groove modulation.
The typical maximum modulation is ~25cm/s
This would result in a maximum cart signal of 25/5*3 ~ = 15mVac
Applying 43dB of RIAA gain gives a maximum output of inv log(43/20) * 15 = 141.25*15 = ~2.12Vac
Are my numbers correct?
Is my method correct?
Yes your method and numbers are good. I had calculated those numbers when I was preparing the FSP so it will be about -10dBV (consumer output standard) at 0dB (5cm/s velocity) and that a loud record will bring about as much volume at peaks as the CD max RMS (0dBFS). So not to overload line pre amps of unknown headroom spec. Then I had listened to typical music records and CDs from my collection flicking the input selector between sources. The mastering levels are all over of course in both mediums but roughly the FSP will sound loud enough next to CD if a reasonably dynamic record is replayed. Not to have you adjusting volume all the time between sources due to great differences at least.
Glad to know I am still awake and thinking straight.
I suffered a bout of transient memory loss (lasting about 90minutes) recently after a day out at the beach. Weird, no recollection of anything during the incident, nor any knowledge that some part of my very recent existence had gone, forever.
Fortunately I was not alone and my friend stopped me from driving into town because she realised I was not "right".
I suffered a bout of transient memory loss (lasting about 90minutes) recently after a day out at the beach. Weird, no recollection of anything during the incident, nor any knowledge that some part of my very recent existence had gone, forever.
Fortunately I was not alone and my friend stopped me from driving into town because she realised I was not "right".
The board level sinks ain't big enough. Ask Stajo who trimmed his board's edge and used bigger external sinks if he ever run a comparison. Me I only run it standard.
I got everything set for 60+ dB on FSP and my sound is perfect. I never got such detailed and live-like sound coming from my TT. So, the NOISE that I was fighting for so long is gone and it was coming from my damaged cart's coils. Man, I suspected and tested, and changed so many things assuming it is PSU ripple, GND loop, bad cables, RF and EMI....
It was cartridge!!!!
I'm more than happy with my setup now.
Please see my build pictures (as Salas asked) taken about 6-7 month ago when I just finished my FSP. I already uploaded them once, but for the guys who did not see....
Couple changes vs. to what I have today in my FSP:
1. R13 is Mills MRA-5
2. R1X is Caddock MP930
3. C2X is EVO Aluminum Oil, instead of EVO Aluminum
It was cartridge!!!!
I'm more than happy with my setup now.
Please see my build pictures (as Salas asked) taken about 6-7 month ago when I just finished my FSP. I already uploaded them once, but for the guys who did not see....
Couple changes vs. to what I have today in my FSP:
1. R13 is Mills MRA-5
2. R1X is Caddock MP930
3. C2X is EVO Aluminum Oil, instead of EVO Aluminum
Attachments
Hi Salas,
Many thanks! The needed information is in a PDF near the beginning of this thread? I'll just ask if I need anything else. Looks straight forward.
Hi Alex,
Thank you for posting those pictures. I LOVE your case, it's exactly my style. Too bad I couldn't match your work in a million years. You have more than enough reason to be proud of your work. I am serious, it's lovely!
Mine will be done in a way that might be acceptable to be seen. I've been playing with the idea of putting my next projects into test equipment cases, the older HP style. Cosmetics aren't my strength.
-Chris
Many thanks! The needed information is in a PDF near the beginning of this thread? I'll just ask if I need anything else. Looks straight forward.
Hi Alex,
Thank you for posting those pictures. I LOVE your case, it's exactly my style. Too bad I couldn't match your work in a million years. You have more than enough reason to be proud of your work. I am serious, it's lovely!
Mine will be done in a way that might be acceptable to be seen. I've been playing with the idea of putting my next projects into test equipment cases, the older HP style. Cosmetics aren't my strength.
-Chris
Hi Chris,
Thank you. BTW, these boxes purchased raw from some guy live in Quebec about 2-3 years ago. He retired and does not make them anymore. Very nice enclosures and easy to work with. I buy boxes from eBay too. Not bad actualy. Please see this one. I just use it for my first made phono called BHL.
BZ2409H Silver Full Aluminum Enclosure Mini Amp Case Preamp Box PSU Chassis | eBay
I asked that guys to send me one with the IEC opening for PSU and other without any holes it for Phono. Not bad quality and quite easy to drill.
I also use his feets. They kinda of small, so you can use 40mm diameter if you want.
4X Aluminum Feets for Power Amp with Rubber Ring D 29mm H 15mm | eBay
Thank you. BTW, these boxes purchased raw from some guy live in Quebec about 2-3 years ago. He retired and does not make them anymore. Very nice enclosures and easy to work with. I buy boxes from eBay too. Not bad actualy. Please see this one. I just use it for my first made phono called BHL.
BZ2409H Silver Full Aluminum Enclosure Mini Amp Case Preamp Box PSU Chassis | eBay
I asked that guys to send me one with the IEC opening for PSU and other without any holes it for Phono. Not bad quality and quite easy to drill.
I also use his feets. They kinda of small, so you can use 40mm diameter if you want.
4X Aluminum Feets for Power Amp with Rubber Ring D 29mm H 15mm | eBay
Attachments
Yes Salas, I remember Stajos work and I hope he will give a view.
Still, would it give anything regarding stability or numbers?
Not that I in any way am unsatisfied with the sq - I'm still amazed and still enjoying it!
Alex - that setup is wonderful. Amazing
Regards
Hi Chris
Yes, its the third link from post#1. For convenience, here it is again.
Official PCB version guide MC & MM
Yes Salas, I remember Stajos work and I hope he will give a view.
Still, would it give anything regarding stability or numbers?
Not that I in any way am unsatisfied with the sq - I'm still amazed and still enjoying it!
Alex - that setup is wonderful. Amazing
Regards
In general such architecture of regs drops output impedance bit further and also cares less about AC modulation THD on rails from the load swing when you run them high CCS current. This one on FSP will keep its 100 deg phase margin if you will boost it from about 100mA as it is now to 250mA for instance, but its unity gain cross point will go further up in bandwidth. What we don't know is how much the FSP itself would subjectively have responded to those things in an A-B comparison for him or different listeners in his or other sound systems. The swing and current demands are not great neither insignificant in FSP but there are several local RC cells for noise filtering that could mask some advantages more than in DCB1 for example. More circuitry and housekeeping here. FSP has it's reg smack to its well defined sum consumption node with very short Kelvin traces and sub stars for the stages zero returns to a main one too. Its a different implementation to the single stage DCB1 in enough ways.
Yes Salas, I remember Stajos work and I hope he will give a view.
Still, would it give anything regarding stability or numbers?
Not that I in any way am unsatisfied with the sq - I'm still amazed and still enjoying it!
Alex - that setup is wonderful. Amazing
Regards
Hi. I never hotrodded anything but I did put some larger sinks on. It was mostly because I wanted to box it kind of narrowly together with other components, like chip volume control, an DCB1 and a DAC. It is not done yet, Ive been making a new electrical system on a ship all summer.
I did some measurement on temps parallell with volatage stability over time and as I recall it I got very stable values after 20 min to half an hour after initial startup, which is what is described in the manual so no big change there. The values are somewhere back in this thread I beleave. My primary goal was not to shorten the startup stability sequence but merely to make a system that stays stable over time and not getting affected to much by outside temp and by other comps in the box. Hence the oversizing and the configuration that the sinks vents to the outside air and not inside the box.
Andrew, wish you well, take care!
If you will ever be in hot-rod mood just solder 4.7 Ohm 5W over the 15 Ohm CCS set resistors so to make thermal and subjective observations. As you mentioned, we should not forget that one of the reasons we kept it a lower heat build is that it has to be in a box for most builders and high current heat can side effect the signal JFETS operation points much more in a high gain phono than in an actively CCSed operation point line buffer.
*Not everybody, your sinks will become barbecue grills, only Stajo that has external bigger ones
*Not everybody, your sinks will become barbecue grills, only Stajo that has external bigger ones
I could test it later on. The sinks will have its own airflow just for the purpouse of not affecting the signal JFETS more then necessary. The signal side of the NJFET RIAA will stay in its own compartment of the box, pretty much without airflow. The PSU side, ie the sinks, gets shut of by a wooden contruction to the sinks compartment which have vent holes in the casing.
The internet, if it's to be believed, that it usually only occurs once, very few ever get a repeat episode.
We blamed sunstroke/dehydration for the incident. (yes, it can happen in Scotland!)
But it's weird that I was completely unaware after the event, that 90 minutes was missing from my life.
And I did report to the Doc two days later on a different issue. She seemed not too concerned other than report immediately if there is ever a repeat. Now I need a Nanny to check if I'm in the middle of an event.
Can she be a gorgeous 30 something?
40 something is just about acceptable, any volunteers?
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