This project started as a experiment after reading the Solidophono article at TNT-Audio website. I was interested in the SSM2017 opamp so I’ve decided to give it a try.
On my project I’ve decided to go for a bit different topology using a split RIAA equalization. All my previous projects were created using a traditional passive equalization so I was exited to see the results.
The whole preamp is made of two stages. The first one is built around the SSM2017 amplifier from Analog Devices.
One could use the modern substitutes – SSM2019 or INA217. The gain of the first stage was set at 60dB! The second stage uses the OPA627 opamp from Texas Instruments. One could experiment with a variety of opamps here. The gain was set to 2. I used a jumper to change the second stage gain to unity in case no further amplification was needed.
The complete schematic for this project can be downloaded >>> HERE <<< Some pictures of the finished PCB. The project is using two separate aluminum boxes. One for the PSU and one for the preamp PCB itself.
The finished PCB inside a nice aluminum box.
The four voltage regulators are placed on the PCB. I’m using a small 20VA toroidal transformer to power up the whole thing. Here is the PSU section:
As you can see, this is a serious power supply. Such configuration could be seen in some expensive power amplifiers. Such a PSU has a very high ripple suppression and since the current demands are no big issue in RIAA preamps, it’s affordable and easy to build as well.
So how does it sound?
Well, I’m not going to describe my own creations as my judgement could be a bit subjective. However I could say this preamp has some very good dynamics with good transient attack.
I encourage you to try this project and see for yourself.
WARNING: The project is provided to the DIY community for free. As such it can only be used for personal needs and NOT for commercial usage.
THANKS FOR READING THIS ARTICLE.
those are just the names of the supply rails. I use separated supply rails for left and right.
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Hi, Why do you have +/- 15.1V and 15.2V supply rails ? ie. 15.1V for Ch1 and 15.2V for Ch2 ?
Great work by the way.
the voltage regulators for both positive and negative supply rails are simple emitter followers + zener. The LM317 regulators serve as a constant current sources/sinks. They replace the usual current limiting resistor for the zeners. This way a better ripple rejection is achieved.
“I encourage you to try this project and see for yourself.”
I think I will. I built an SSM2017 stereo balanced mike pre amp with great low noise results. Your project looks awesome.
Re your -ve supply rails: Why didn’t you use LM337 regulators ? I’m still trying to get my head around the LM317 arrangement in the -ve supply circuits.
The LM317 regulators serve as a constant current sources/sinks.
I suspected this, but had never thought about using the LM317 ‘upside down’,so to speak, in a -ve rail application.
I would have mirrored the +ve circuit with a LM337 in the -ve rail.
Your’s is a very clever design.
The OPA627 is US$30 each from Mouser. Crazy price! I thought about using OPA827 instead. (Free sample) It’s still a low noise device.
I have half a tube of SSM2017, so will make a start on this project.
Thankyou for sharing it.
R J ones
Nice design, can you supply a pcb for this project
Very good day. I recently subscribed to your page. I found it looking a PCB for Solidphono.
2 years ago I built this preamplifier as indicated on page TNT, you’ve only used the SSM2019.
But with proper design of PCB source as both preamps but I fear they are not adequate.
I tried it without making the final installation, and actually looks pretty good.
But seeing it done for you, I was interested.
Can you provide me PCB design?.
I would appreciate to help make this project.
From already thank you very much.
Hello. Good morning (in these latitudes).
Sorry for the inconvenience and insistence.
As I have already told you, I have assembled the circuit published on TNT on a homemade pcb.
But I would really like to assemble your circuit, but I don’t know how to do a PCB layout.
Could you sell me the PCB for your project, or if this is not possible, could you sell me the Gerber file so I can send it to be manufactured?
I would be very grateful, since I have seen your design for years and I want to make it.