Wednesday, November 25, 2020

“Carbon” - chip based phono preamp

 















A mix of MKT, Polyester and low ESR electro caps. All carbon film Rs through. Differential PS onboard. Genuine OPA2134 from RS and machined milspec socket. Two 9V batteries for about 50 to 100 hours play depending on battery type. I often use eBay lithium’s first 100 hours.

 

Cast Al enclosure with bituminised heavy Al in the bottom for resonance and vibration control. Paint is Epoxy Enamel with an etching primer. The finish is gloss and tough. This one is also called “Carbon” for obvious reasons. 

 

Some don’t like carbon film resistors but I find they produce a very smooth sound but still let instruments shine in their own space. The preamp is new and requires about 50 hours to burn in. Listening to it with late model Rega P3 and Gerrott P77i cart. Very nice and to think it will improve

Monday, November 16, 2020

“Succinct II” - integrated 180W Class D amp with tube preamp

 









The original Succinct was built on commission and again it was a 180W Class D amp. The owner lost all in our latest bushfires. By accident I found this out and offered to replace the amp for cost of parts only. We added a tube preamp to make this a true integrated. 

It is all housed in a light weight 2U charcoal 19” rack mount. There are two inputs selected by a small front switch. The onboard PS with the hifimediy T4 module is used here and a Radi0kit 12V/250V PS is used to power the tube section. The tube is a Raytheon 12AU7 and the preamp is built on a small piece of Vera-brd. The tranni is 300VAC and connects direct to the amp module. The amp module has speaker crowbar protection. Twenty second delay on and immediate off. 

The sound, as usual from these T4 modules, is pristine, very detailed and with excellent bass drive down to 30hZ the limit of my speakers. For way under $AU1K this map has a stack of power (180W into 8ohms) and crystal clear with only a touch of tube warmth.