Phono 70

                                                 Introducing the Paradox Phono 70
 The 70 (70db of voltage gain) is a low output Moving Coil (MC) phono amplifier.
There are no switches in the signal path, switches degrade sound period.
 
Highlights of great importance;
70db of overall voltage gain, will work with 0.1mv MC cartridge.
Passive RIAA, using Audionote tantalum resistor and matched precision parts for highly accurate full range equalization.
PI filtered power supply with Mundorf Mlytic, styrene bypasses and isolation.
Simple ultra-low noise JFET circuit using the LSK170.
PIO coupling capacitors.
Cardas phono wire for signal and power path.
Special RIVER circuit board technology, must be engineered for each product, is not a program.
Input impedance 100k ohms with infinite loading possibilities via external load RCA’s.
Completely hand built and assembled, damped rigid chassis and high quality connections.
Separate DC power supply at 18VDC. It is acceptable for the supply to be up to +/-0.5VDC off.
Upgradeable components for the 70, DC power supply, DC umbilical cord, Pulse AC power cord.
Two year warranty bumper to bumper.
 
LOADING read thoroughly with intent to understand;
Input impedance of 100k ohms is on the board permanent load, your external load is in parallel and necessary for the MC cartridge to sound proper.
NO damage can occur if an external load is not present but the sound will not be right.
The use of external load is in parallel to the 100k making your actual value slightly less than actual load resistor value, so 500-ohm load resistor may be something like 495 ohms. This difference is unimportant.
Load resistors are a component that goes from the input signal to ground/"0".
There is no advantage whatsoever in using anything but precision (metal film) resistors as it will NOT matter sonically since it goes to ground!
Loading is very misunderstood and I hope this helps your understanding.
 
Load resistor mounting;
A pair of 400-ohm resistor has already been inserted into the screw down RCA as an example.
I like to bend the ends of the load resistor back over on itself a 1/4" and then insert into the end of the RCA with the screw terminals, this provides more bite for a secure connection but is not necessary.
Loosen RCA screw end in preparation for the load resistor. Insert ends of resistor and tighten screws down. Most of the MC cartridges I have used like 400 to 700 ohms (500 ohms being the most used) for a load. Since the load acts as a dampening across the coils of the cartridge only you and your system will know the correct values.
Build as many different values as you like but you will have to label them to keep order.
It is easy to get them mixed up if YOU don't use caution and keep pairs together.
You can also build your own male RCA's with a resistor soldered in place but the sound will NOT improve so why waste the money.
 
Specification of no sonic merit; subject to change.
SNR: >80db
ID: 0.001
THD: <0.01%
Internally there is a lot going on. The RIVER circuit board is noticable in the ground and signal planes.
Parts quality is as good as it gets, well almost as the Signature Phono 70 is coming soon.

This is what the back looks like befor being mounted to the chassis. There are Right and Left inputs, loading RCA's and signal out.
Power connection and grounding point.

The Phono 70
Bottom view; very simple mounting points for circuit board and rubber feet. Chassis internally is also damped.
If you would like higher levels of isolation it will be up to you!

70dB of passive RIAA super low noise JFET gain. This will make everyone who uses Step Up Transformers (SUT) and/or RIAA gain circuits obsolete. No matter what topology being used, tubes or solid state, all before will sound broken by comparison!