Thanks a lot sq, thats all correct. Please check the documents available through the link in my signature for schematic, build guide, etc
No production run planned as of today, sorry!
No production run planned as of today, sorry!
Lowering the gain?
Is there an alternative method other than replacing the emitter resistors? I need to trim c10db for a friend who has a clipping input stage on his A/D
Is there an alternative method other than replacing the emitter resistors? I need to trim c10db for a friend who has a clipping input stage on his A/D
The other way is changing the components in the RIAA.
10 dB is a factor of aproxinately 3. So you have to lower the resistors by a factor of 3 and raise the value of the capacitors by a factor of 3. Gain in a transimpedance stage is :
Gm x R so lowering the resistors lowers the gain. When you lower the resistors you have to raise the capacitors acordingly or the time constants will be wrong.
Working on the emitter resistors influences Gm so raising the value of the emitter resistors lowers Gm proportionally.
10 dB is a factor of aproxinately 3. So you have to lower the resistors by a factor of 3 and raise the value of the capacitors by a factor of 3. Gain in a transimpedance stage is :
Gm x R so lowering the resistors lowers the gain. When you lower the resistors you have to raise the capacitors acordingly or the time constants will be wrong.
Working on the emitter resistors influences Gm so raising the value of the emitter resistors lowers Gm proportionally.
Last edited:
Thanks joachim, pulling all eight resistors in that location on the pcb is a ball ache, as is redoing the riaa, looks like he'll have to use inline attenuators on the RCA cables.
In a feedback RIAA this is easier. Only one resistor. Not here.
I think the inline attenuation will work. Noise of the phono stage will be attenuated this way but you loose a bit of dynamic range. The best dynamic range you get when at maximum volume you do not get any overload. It is better to attenuate after a gain stage then before it.
I think the inline attenuation will work. Noise of the phono stage will be attenuated this way but you loose a bit of dynamic range. The best dynamic range you get when at maximum volume you do not get any overload. It is better to attenuate after a gain stage then before it.
I have been using version R2 for quite a while with no problems. Recently I have developed a hum in one channel. It is not a power supply problem. I have resoldered all the input and output signal wires. I have jiggles all the parts with no change to the hum. Any ideas would be greatly appreciated.
Regards,
Mas
Regards,
Mas
A worn out electrolytic ?
Can you measure PSU ripple with your DMM set to AC voltage?
If not then you can attach a capacitor in series with the probe and that isolates the DC component from the DMM and you then set the Vac scale starting at the highest and go down until you reach a sensible reading that is just inside the scale range.
The Vac needs to be multiplied by ~3 to arrive at a very rough approximation of the Vpp you would read on a scope.
Can you measure PSU ripple with your DMM set to AC voltage?
If not then you can attach a capacitor in series with the probe and that isolates the DC component from the DMM and you then set the Vac scale starting at the highest and go down until you reach a sensible reading that is just inside the scale range.
The Vac needs to be multiplied by ~3 to arrive at a very rough approximation of the Vpp you would read on a scope.
More likely the arm lead and cart tags than the Paradise. Try another phono stage before going mental.
No problem....hope to hear from you soon...i.e. when you find 10 minutes to answer to my questions 😛
Thanks!
Stefano.
Thanks!
Stefano.
I have been looking at my paradise pcb´s finaly.and I wonder what resistors should I use as input loading and what switch?
I prefer to shop from mouser.
Beeing a newbie with vinyl players I wonder what will the result be if I don´t use the loading resistors at all?? 😕
I prefer to shop from mouser.
Beeing a newbie with vinyl players I wonder what will the result be if I don´t use the loading resistors at all?? 😕
Hi,
have a look for the TE Con's LR1 1% and YR1 0.1% series at Mouser.
Both types feature thin films of a NiCr alloy, pressed on metal end caps and tinned copper wire legs for low money in 0207 casings.
jauu
Calvin
have a look for the TE Con's LR1 1% and YR1 0.1% series at Mouser.
Both types feature thin films of a NiCr alloy, pressed on metal end caps and tinned copper wire legs for low money in 0207 casings.
jauu
Calvin
Ryssen: if no lossning resistor is used i have understand then that the input impedance will be 10K. For most (certainly not all) mc cartridges this will be way to high, resulting in a bootsted treble... most low output mc cartridges are loaded with less then 1K...
Hi, please take a look at the documents (link in my signature), I have used Dale RN65 resistors for the loading and a C&K rotary switch with silver contacts. Works very well.
Now, what should be a good loading IMHO depends on the cartridge and your preferences. There are people that say that the loading resistor should be 2...4 times the cartridge DC resistance, others like to use 47k for MC..... The "native" input impedance of the Paradise is around 10k, so higher load resistors will not change anything.
My recommendation would be to use a good test record (e.g. Dr. Feickert) and measure the frequency response of your setup, then tune the load resistance to linear response in the treble, and use this as a starting point for listening optimization. Just my two cents.....
have fun
alfred
Now, what should be a good loading IMHO depends on the cartridge and your preferences. There are people that say that the loading resistor should be 2...4 times the cartridge DC resistance, others like to use 47k for MC..... The "native" input impedance of the Paradise is around 10k, so higher load resistors will not change anything.
My recommendation would be to use a good test record (e.g. Dr. Feickert) and measure the frequency response of your setup, then tune the load resistance to linear response in the treble, and use this as a starting point for listening optimization. Just my two cents.....
have fun
alfred
Will this one work allright?
http://www.mouser.se/ProductDetail/...JDZNNSWJmylnlaMPozB5myi%2bzW0w66Q409NPoerPg==
http://www.mouser.se/ProductDetail/...JDZNNSWJmylnlaMPozB5myi%2bzW0w66Q409NPoerPg==