Sk,
the hole for an XLR is not round.
It needs you to shape the hole to fit the back of the socket.
For very good RF attenuation you need many electrical contact points around the perimeter of that close fitting hole.
This way the socket becomes part of the "Chassis".
the hole for an XLR is not round.
It needs you to shape the hole to fit the back of the socket.
For very good RF attenuation you need many electrical contact points around the perimeter of that close fitting hole.
This way the socket becomes part of the "Chassis".
Yup, I think I might get one of those instead of drilling, dremelling and filing like a mad man. My Neutrik connectors are definitely round, although with notches on the sides if that's what you're referring to Andrew.
Something to consider
I have meant to post this and keep forgetting.
I read many years ago that when using LEDs as we are in the SALAS phono stage that one must shield the LEDs from light. Not just light used to illuminate a room but from light from the other LEDs.
Seems that a small voltage is produced when the LED is exposed to light.
Wish I could remember the source of this. I will try to look around and supply. Since I am in the middle of having to replace two sets of LEDs - one with a bad one in the middle and one I installed backwards (damnit) but after I verify that all is working I am trying to think of the best way to shield them from light.
Maybe tubes made of adhesive tape or little glops of MOR-TITE? I know it sounds nutty but I remember the phenomena being verified by someone who knows, not a goofy tweaker like myself. As I think about it I think it was first written about in the BOTTLEHEAD forum about their constant current source which uses LEDS.
Of course, this will not make a night and day difference but the key to tweaks is the cumulative effects of them all. Of course, one can then argue if they end up offsetting each other and all sorts of arcane arcana ...
I have meant to post this and keep forgetting.
I read many years ago that when using LEDs as we are in the SALAS phono stage that one must shield the LEDs from light. Not just light used to illuminate a room but from light from the other LEDs.
Seems that a small voltage is produced when the LED is exposed to light.
Wish I could remember the source of this. I will try to look around and supply. Since I am in the middle of having to replace two sets of LEDs - one with a bad one in the middle and one I installed backwards (damnit) but after I verify that all is working I am trying to think of the best way to shield them from light.
Maybe tubes made of adhesive tape or little glops of MOR-TITE? I know it sounds nutty but I remember the phenomena being verified by someone who knows, not a goofy tweaker like myself. As I think about it I think it was first written about in the BOTTLEHEAD forum about their constant current source which uses LEDS.
Of course, this will not make a night and day difference but the key to tweaks is the cumulative effects of them all. Of course, one can then argue if they end up offsetting each other and all sorts of arcane arcana ...
First article I found
Not sure exactly how this affects things but when we go to so much trouble to give a circuit a stable baseline ...
https://led-brdf.wikispaces.com/Led+Sensing+and+Spectral+Sensitivity
Not sure exactly how this affects things but when we go to so much trouble to give a circuit a stable baseline ...
https://led-brdf.wikispaces.com/Led+Sensing+and+Spectral+Sensitivity
We use them as combined voltage reference here. What if one changes something little to the other by shining? Giving bit different Vf total when together than adding their Vf when tested individually at same current maybe? No problem to our purpose. Slight self noise differentiation when together? We filter them as a team with a large cap across anyway. Their resistance adds up so the filtering is deeper for a row of LEDs vs a single LED.
Now listening to the folded with a Colibri XGP..... incredible resolution and poise. Set Rload to 1000ohms and VTF to 1.35g.
It is in another league compared to the Benz LP and even the Kiseki I had before.
The koetsu black is quite musical also but does not have this insight.... I wonder what a Atlas can sound like connected to this superlative riaa 🙂
It is in another league compared to the Benz LP and even the Kiseki I had before.
The koetsu black is quite musical also but does not have this insight.... I wonder what a Atlas can sound like connected to this superlative riaa 🙂
I have been told again in the past that Colibri XGP + FSP make a great duo but unfortunately I could not hear it myself because that system is in the Austrian Alps. Seems true in the Swiss Alps too. Must be the Colibri and FSP like to yodel.😀
Ready to install in the box
Both of my boards are working though I have not yet connected them to an amplifier.
Thought I would mention a few things before doing so.
My voltage at the B+ input is 50 volts, The most I can get at rail/ground is just under 33 volts - even with the pot turned all of the way up.
I have got the 3.6 v though I did not go back and see what rail/ground read once this was achieved. Patience is necessary for this! I was very surprised how even breathing on the board affected the bias. I ended up putting a piece of wool velvet over the board to stabilize the reading. It was unusually cool in Atlanta over the weekend so my house was unusually cool, also.
Does my rail/ground reading seem strange? I am hoping that it doesn't matter.
Sometime this week I will have all of the other wiring done and be able to connect it to my system. I would like to think this will happen tonight but one can never be too sure.
Any comments are welcome and needed.
Both of my boards are working though I have not yet connected them to an amplifier.
Thought I would mention a few things before doing so.
My voltage at the B+ input is 50 volts, The most I can get at rail/ground is just under 33 volts - even with the pot turned all of the way up.
I have got the 3.6 v though I did not go back and see what rail/ground read once this was achieved. Patience is necessary for this! I was very surprised how even breathing on the board affected the bias. I ended up putting a piece of wool velvet over the board to stabilize the reading. It was unusually cool in Atlanta over the weekend so my house was unusually cool, also.
Does my rail/ground reading seem strange? I am hoping that it doesn't matter.
Sometime this week I will have all of the other wiring done and be able to connect it to my system. I would like to think this will happen tonight but one can never be too sure.
Any comments are welcome and needed.
Congrats for solving your LEDS situation. For the 369s thermal thing please read this post: http://www.diyaudio.com/forums/analogue-source/129126-simplistic-njfet-riaa-1215.html#post3835719
The credit goes to Mr. Thomas for his irreplaceable counsel during my build.
One of the great partnerships in DIY audio, SALAS and TEABAG! We are very lucky that the both of you are willing to help us out with designs and what is needed to make something we could not have, otherwise.
Not that the temp thing is bothersome. I know it will be controlled when enclosed. Not having worked with FETs before I was very surprised by the phenomena. I know you had given warning, I just did not expect such sensitivity. I surmise a device as sensitive to temperature is probably just as sensitive to the tiny signal it is being given to amplify.
I will find a way to keep that resistor and the FETs to a constant temperature, no need for more parts in a simplistic phono stage!
Again, gratitude for both of your efforts is hard to verbalize.
One of the great partnerships in DIY audio, SALAS and TEABAG! We are very lucky that the both of you are willing to help us out with designs and what is needed to make something we could not have, otherwise.
Not that the temp thing is bothersome. I know it will be controlled when enclosed. Not having worked with FETs before I was very surprised by the phenomena. I know you had given warning, I just did not expect such sensitivity. I surmise a device as sensitive to temperature is probably just as sensitive to the tiny signal it is being given to amplify.
I will find a way to keep that resistor and the FETs to a constant temperature, no need for more parts in a simplistic phono stage!
Again, gratitude for both of your efforts is hard to verbalize.
Salas,RCruz,others,
If you had to splurge on resistors other than the 47k in the signal path, where would you do so? Cartridge loading resistors? 6.8K RIAA? I have foil for 47k, but didnt know if the others would have as big an impact.
If you had to splurge on resistors other than the 47k in the signal path, where would you do so? Cartridge loading resistors? 6.8K RIAA? I have foil for 47k, but didnt know if the others would have as big an impact.
Thanks for your kind words. Nobody here found the 369s Tempco thing to be an unsurpassed practical obstacle yet. Drastic input FETS current bias stabilization means more active parts in the most sensitive signal area and its logical to try avoid if possible but not something to be afraid to test on the other hand if really needed in an installation with too much of an ambient delta. The information is there if any need will arise. It will up the input stage PSRR is a benefit despite some extra hiss that could be audible or not given the cart output and gain setting specifics. This discussion is irrelevant to the MM and HMC builds as they are far less prone to their 369's positive Tempco by design.
Cartridge load resistor(s), Riaa filter area resistors, collector and drain load resistors.
I don't recall reading this. But, what about RIAA capacitors. Other than PP, that is. Anyone try Russian K75 styrene, or the teflons? Any advantages?
Where am I going wrong, SALAS?
All of my LEDs are lit. My rail/ground just under 34 volts. I add 1.66K R to 6.2K RR3x to see if this will increase rail/ground V. It does, barely, but the LED trio goes dim and TP1/TP2 sinks to approx .7V.
Take away the 1.66K from R3x the LEDs return to bright but TP1/TP2 stays at .7 V.
What do you suspect has died?
THANKS!
All of my LEDs are lit. My rail/ground just under 34 volts. I add 1.66K R to 6.2K RR3x to see if this will increase rail/ground V. It does, barely, but the LED trio goes dim and TP1/TP2 sinks to approx .7V.
Take away the 1.66K from R3x the LEDs return to bright but TP1/TP2 stays at .7 V.
What do you suspect has died?
THANKS!
Unfortunately
Turning the pot does nothing - the TP1/TP2 stays around .7 Not sure if it means anything but the LEDs brightness does not change, either, when turning the pot. Rail/Ground down to 30 with no change.
Input voltage is 50.
Rail/Ground - max 35.2
TP1 to ground 8.03
TP2 to ground 8.75 with Rail/Ground at 34.4 (where it was when I measured it)
Does this give any clues?
Turning the pot does nothing - the TP1/TP2 stays around .7 Not sure if it means anything but the LEDs brightness does not change, either, when turning the pot. Rail/Ground down to 30 with no change.
Input voltage is 50.
Rail/Ground - max 35.2
TP1 to ground 8.03
TP2 to ground 8.75 with Rail/Ground at 34.4 (where it was when I measured it)
Does this give any clues?
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Say you test TP2 to ground while turning VR2X, no change again? See if Q3Y (or Z) are in the right place for BC560C or 2SA970 type when following the instructions and board print.
In response
Starting with rail/ground at 35.2 (fully clockwise) TP2 to ground - 8.08
with rail/ground at 31.9 - TP2 to ground - 7.96
Q3Z is oriented correctly - remember when I first connected to B+ I could get the 3.6V but rail ground was just below 34 V. It worked before but I was concerned about the low reading of rail/ground and that is when the extra resistance was added to the 6.2K R3x and that dimmed the trio of LEDs and my TP1/TR2 went to .7__ and that is where it has stayed even after the removal of the extra resistance (1.66K).
TEA BAG has suggested that I replace Q3x with another 2SK117 - I have one that measures .6. I dread having to do this and thought I should be sure it was a possibility before proceeding. Pretty tight in there - figure it would be best to remove R3x before doing this. Plus to make it easier I was, with the assumption that the device has been destroyed, to simply wiggle it back and forth to break the leads and then clean up the holes from the back of the board.
AS ALWAYS I greatly appreciate your counsel!
Starting with rail/ground at 35.2 (fully clockwise) TP2 to ground - 8.08
with rail/ground at 31.9 - TP2 to ground - 7.96
Q3Z is oriented correctly - remember when I first connected to B+ I could get the 3.6V but rail ground was just below 34 V. It worked before but I was concerned about the low reading of rail/ground and that is when the extra resistance was added to the 6.2K R3x and that dimmed the trio of LEDs and my TP1/TR2 went to .7__ and that is where it has stayed even after the removal of the extra resistance (1.66K).
TEA BAG has suggested that I replace Q3x with another 2SK117 - I have one that measures .6. I dread having to do this and thought I should be sure it was a possibility before proceeding. Pretty tight in there - figure it would be best to remove R3x before doing this. Plus to make it easier I was, with the assumption that the device has been destroyed, to simply wiggle it back and forth to break the leads and then clean up the holes from the back of the board.
AS ALWAYS I greatly appreciate your counsel!