Should I make a Phonoclone or VSPS for the Shure M97xe cartrdige? I'm not sure if it's high or low output.
Thanks, shouldn't be a problem
Thanks, shouldn't be a problem
Dunno. Have you googled it?
That's why I used ones from my bits box. It's always worth gathering old broken kit to salvage for spares. Traffos rarely go wrong, and you can salvage many other goodies as well, such as caps, enclosures, etc. Why not stick an ad on your local freecycle list for any old or damaged hi-fi?
The X-reg PCB design is there for you to download and make your own boards or fab them at Olimex or wherever. I don't have them for sale. The closest option would be to use a set of VSPS300 or Phonoclone 3 boards and just populate the X-reg section, taking the output from pad 4 and pad 7 of the unpopulated opamp socket IC1.
/R
/R
No, there is not. A 25 VA toroid will set you back about $25 + shipping. Considering the amount of time and effort that goes into building the phono preamp, it seems to me odd to skimp on the power supply (and the sound) for the sake of saving such a small amount of money.
That said, yeah, I went through that "must scavenge everything from old techtronix 'scopes and computer power supplies" phase myself. The day eventually comes when the time vs. money equation tips in favor of "just buy the damn part".
/R
I'll have to find some other traffos first, I doubt the X-Reg would like 25V up it!
Pinkmouse,
The fundamental limitation of the X-reg design is set by the maximum power supply voltage on the opamps, spec'd at +/-22V for the OPA27. The input voltage is dropped through R9 and R10 before it is applied to IC3 and IC3, but for a practical safety margin I would not use it with V++ V-- supplies above 20 V.
/R
A question about the resistor values. I'd like to use the exact values for the VSPS (105k and 732k), but I can't find those values. Would it make a difference if I just connect several resistors in series? I'll be sure to use a multimeter to get the values right.
Yeah, I've opened up some old hifi products (Technics tuner, amplifier, cassette player), but they didn't have a toroid transformer, so I'll just buy one.
Yeah, I've opened up some old hifi products (Technics tuner, amplifier, cassette player), but they didn't have a toroid transformer, so I'll just buy one.
R1 balances the cartridge input impedance. Making it bigger will increase noise, making it smaller will decrease the input noise overall but could increase certain kinds of distortions.
C3 blocks DC and attenuates low frequencies. If it is too small the bass response will be limited. Making it exceptionally large, however, will not increase the bass response further and may sound poor due to distortions of the capacitor.
C3 blocks DC and attenuates low frequencies. If it is too small the bass response will be limited. Making it exceptionally large, however, will not increase the bass response further and may sound poor due to distortions of the capacitor.
Matching cartridge impedance
Dear Richard,
in order to choose values for R1 and R2, I have similar questions than the ones posted before.
My cartridge is an old Benz Micro Reference (first series) that has the following technical specs
output voltage 0,26mV at 3,54cm/s
internal impedance 3,5 ohms
recommended loading 50-47.000 ohms
I know the output is quite low, so using a value for R2 that is above the 1k you recommend in the BOM is appropriate? Does that increase the tendency to pick up hum?
And for R1: Do I use any value that is similar to the internal impedance, in my case 3,6R?
Thanks for shedding some light on this. At the moment: everyday is a schools day for me, as I am a newbie to the DIY community, and I want to get that project right.
kind regards, Ulrich
Dear Richard,
in order to choose values for R1 and R2, I have similar questions than the ones posted before.
My cartridge is an old Benz Micro Reference (first series) that has the following technical specs
output voltage 0,26mV at 3,54cm/s
internal impedance 3,5 ohms
recommended loading 50-47.000 ohms
I know the output is quite low, so using a value for R2 that is above the 1k you recommend in the BOM is appropriate? Does that increase the tendency to pick up hum?
And for R1: Do I use any value that is similar to the internal impedance, in my case 3,6R?
Thanks for shedding some light on this. At the moment: everyday is a schools day for me, as I am a newbie to the DIY community, and I want to get that project right.
kind regards, Ulrich
There is a worksheet in the BOM named "Phonoclone Gain Calculator".
If you input your cartridge data, it tells you that R1 is 3.5 Ohms and R2 is 134 Ohms.
These are approximate values, adjust R2 from there as appropriate for your system.
The BOM parts values of 47R and 1k for R1 and R2 are highlighted in red, with a comment noting that they must be selected to match the cartridge. The BOM default is for the Denon DL-103.
If you input your cartridge data, it tells you that R1 is 3.5 Ohms and R2 is 134 Ohms.
These are approximate values, adjust R2 from there as appropriate for your system.
The BOM parts values of 47R and 1k for R1 and R2 are highlighted in red, with a comment noting that they must be selected to match the cartridge. The BOM default is for the Denon DL-103.
I need a bit of help wiring the toroidal transformer. It's 100VA 2x12.
To start, it's tightly wrapped in plastic with the wires coming out. Should I remove it? It's good isolation, but if it's dangerous I should remove it.
There are 2 red wires, one blue, one green, one yellow and one black (so six wires total). The description says:
230V 50-60 Hz Rd - Rd EN61558 (I figure these go to the AC)
12V 4.17A Grn* - Yel FUSE T5A
12V 4.17A Bl* - Blk FUSE T5A
What does the * stand for?
Can I ignore the "EN61558"?
Am I supposed to connect a T5A fuse to the 12V wires?
To start, it's tightly wrapped in plastic with the wires coming out. Should I remove it? It's good isolation, but if it's dangerous I should remove it.
There are 2 red wires, one blue, one green, one yellow and one black (so six wires total). The description says:
230V 50-60 Hz Rd - Rd EN61558 (I figure these go to the AC)
12V 4.17A Grn* - Yel FUSE T5A
12V 4.17A Bl* - Blk FUSE T5A
What does the * stand for?
Can I ignore the "EN61558"?
Am I supposed to connect a T5A fuse to the 12V wires?
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See here.
The two red leads go to the AC.
Green and yellow go to the "~" lugs of the first rectifier bridge.
Blue and black got to the "~" lugs of the second rectifier bridge.
The "*" usually indicates the positive phase of the secondaries, but isn't absolute if the phase of the primary winding isn't similarly indicated, and anyway isn't important when you use two rectifier bridges as shown in the linked page above.
T5A indicates a slow 5A fuse is recommended for the secondaries. That's the maximum you should use, it allows the rated 4.17 A to be drawn safely from the transformer. For the phono stage it is not necessary to fuse the secondaries. A single slow 0.5 A fuse on the AC line is sufficient.
The two red leads go to the AC.
Green and yellow go to the "~" lugs of the first rectifier bridge.
Blue and black got to the "~" lugs of the second rectifier bridge.
The "*" usually indicates the positive phase of the secondaries, but isn't absolute if the phase of the primary winding isn't similarly indicated, and anyway isn't important when you use two rectifier bridges as shown in the linked page above.
T5A indicates a slow 5A fuse is recommended for the secondaries. That's the maximum you should use, it allows the rated 4.17 A to be drawn safely from the transformer. For the phono stage it is not necessary to fuse the secondaries. A single slow 0.5 A fuse on the AC line is sufficient.
I seem to be a bit confused again. I want to build the Xreg Voltage Stabilizer. [url=http://phonoclone.com/diy-xreg.html]This schematic[/url] is supposed to be the one to be coupled with the VSPS. But the voltage levels are confusing me.
Shouldn't the input be -12V and +12V? The schematic says -18V and +18V, even though it's supposed to be coupled with a 2X12VAC transformer.
Also, shouldn't the output be -12V and +12V as well? I thought the VSPS worked at 12V and not 9V as the schematic shows.
Shouldn't the input be -12V and +12V? The schematic says -18V and +18V, even though it's supposed to be coupled with a 2X12VAC transformer.
Also, shouldn't the output be -12V and +12V as well? I thought the VSPS worked at 12V and not 9V as the schematic shows.