Yet more Schiit Audio has come to Dismal Manor. Jason Stoddard has designed a little integrated circuit phono preamp that is an incredibly musical and flexible device. Oh, and Schiit Audio sells Mani for the princely sum of $129. And it works. And its dead quiet. Not a hint of hum. That’s insane! It was in impulse purchase.
References
- https://www.schiit.com/products/mani The product page
A quick guide to Mani’s Features
- Most moving magnet and moving coil cartridges are happy
- Several gain settings (30, 42, 47, and 59dB)
- 47 Ohm moving coil and 47 kOhm moving magnet input impedances
- differential input (I assume Jason used the input op amp in differential mode)
- line output
- passive RIAA equalization, no poles in the feedback paths.
- power switch on the back
- 16 VAC power input from an audiophile 🙂 wall wart.
Setting the gain
The input impedance and gain selection switches are on the bottom. Two pair of switches set the gain. These switches are grouped in pairs with each pair having one switch per channel. Both switches in the pair are usually set to the same position. So two switches with two positions gives 4 gains. The manual tells which combination gives which gain.
As Mani comes out of the box he is set up for a high output moving magnet cartridge, 47 kOhm impedance and 30 db gain. Play something fairly loud. If you don’t hear anything, select the next gain setting.
If you are using a moving coil cartridge, change Mani’s input impedance to 47 ohms.
To change gain settings, turn off the downstream device, turn off Mani, adjust the gain switches, turn on Mani, and turn on the downstream device. Mani will make rude noises if switches are operated while Mani’s signal path to output is active.
First Listening Impressions
Mani is quiet, dead quiet. Not a trace of hum if the turntable chassis is grounded to Mani.
Mani has a neutral voice. I listened to Disk 1 Side 1 of Snarky Puppy’s Family Dinner Volume 2. This is an acoustic record, well mostly, well there are horns and drums. The Family Dinner records are incredibly complex with Michael League bass lines warping the space time continuum, complex polyrhythmic percussion lines, horn parts, wailing Moogs, and electric guitars ranging from clean to raunchy. And Jacob Collier brought his vocal harmonizer, a wicked gadget that MIT Media Lab souped up to autotune a vocal mic input to whatever chord the synthesizer is playing.
A Sumiko Black Pearl moving magnet cartridge manages to turn all of this complexity into about a 2 milliVolt signal that has to be amplified, deemphasized, and passed off to the Parasound USB Phono A to D converter. From there, I auditioned the record using Audeze LCD-2 headphones plugged into the Parasound monitor output.
So, I had a preamp, why the second?
The Parasound USB Pre has 2 line inputs and a phono input switchable for moving coil or moving magnet. It offered 2 choice of gain for moving coil and one for moving magnet. The levels were odd when dubbing. I was a little more concerned about headroom. and I recall it being a bit hum sensitive in setup.
The thing that provoked this impulse purchase was the Schiit Audio house sound (neutral and dead quiet), and me researching the balanced connections post. Phono inputs are a natural use of balanced differential inputs yet all my vacuum tube preamps had single ended inputs and were prone to buzz a bit, especially on the quiet bits. After reading the Mani Specs page and looking at the marketing slicks for the integrated circuit operational amplifiers Jason said were inside, I made the guess that clever Jason would connect the cartridge in differential mode to cancel any hum picked up in the leads from turntable to preamp. It is dead quiet.
My pet peeve
When there is a power cut, the rig pops. That’s Vidar grumbling that his power went away but all the others do too. But all of the Schiit Audio gear analog stages prefer to have continuous mains power and will emit output pops when the mains drop.
Dismal Manor Dispatches 