Sunday, February 28, 2021

"La Ruse" - Gold Lion ECC83 SRPP preamp in a plastic jiffy box


"La Ruse" as the name suggest is hiding something. Its under the paint work and similar to "Illusion", its chassis is a plastic jiffy box. This time spray with Ocean Blue hammertone. Mach that with a large gold knob, looks the part. The tubes I've had for years and are Genelex Gold Lions ECC83 gold pin (similar to 12AX7) which have high gain. About time I finally put these premium tubes to work.

All resistors are 1/4W carbon. I like carbon because it appears to produce great musical flow and combined with the high gain tubes produces a big bold sound. No cost cutting with the attenuator which is my favorite Alps Blue velvet and it is on the output. With the pot on the output you are not throwing away precious raw signal by attenuating the input then trying to amplify what remains producing more noise. 

Once more Russian Military paper-in-oil caps are on the output, they always sound good. There are two inputs selected by the small switch at the front. The external PS produces 12V regulated and 250VHT electronically smoothed. All hookup wire in the audio path is silver plated fine copper wire. There is no PCB. Wiring is a combination of  component-2-component and point-2-point. The preamp is dead quiet. La Ruse not only looks good but sounds great and very grounded. 

Friday, February 5, 2021

"Noir" - SRPP Psvane 12AU7 TII preamp


A new preamp all completed in record time. Should be I've probably made eight like this. Sounds detailed, laid back and smooth with the Psvane 12AU7 TIIs. Worked at first on.


Voltages are;

HT = 247V

bias = 2.44V

current = 5mA.


I'm using a Radi0kit external PS kit. Regulated 12V and electronically smoothed HT. Turn it up and it’s dead quiet no hum, buzz, crackle, snap or pop. Looks and sound extremely good. 

Alps pot on the output, Russian PIO output caps and SRPP topology. Metal film resistors. Wood cheeks have been finished with a finishing oil. They really have lifted.  Epoxy enamel paint on top of etching primer.

Thursday, January 28, 2021

"fiih-300" - Holton based 300W power amp


Once again a powerful 300W Holton based power amp using the upgraded 200W modules. These have the more powerful dual die power FETs installed to allow the modules to produce 300W into 8 ohms and 500 into 4. 80,000uf of 100V filter caps all snubbed and an RFI/EMI power filter.

An over size heatsink is used but still runs up to over 50C. Tranni is 500VAC but will be more than enough to drive the hardest loads to high volume. Once more excellent Holton bass depth and control. Clear, transparent mids. Allover an excellent sounding amp. 

Friday, January 15, 2021

“Sortilege” - enhanced Class D power amp


Another 180W Class D amp based on the hifimediy T4 module. This time the input caps have been upgraded to Mundorf EVO oils and an additional 22,000uf of Mundorf MLytic audio grade capacitance has been added to the PS. Total caps with onboard Nichicon is 32,000uf. The filter caps are snubbed. Enclosure is attractive two tone, earthed and fused. A RFI/EMI power filter has been added and a ferrite choke on the power cord to block RFI. A 500VA tranni does the grunt work and the onboard Motorola ultrafast/soft recovery diodes for the rectifying. 

The amp sounds excellent, clean, clear and fast with optimum bass control. For the extra work replacing the input caps and adding the better filter cap the sound quality has improved. Other amp builders who have heard it agreed and its new own is very pleased. So am I.


Saturday, December 26, 2020

“Mantra” - kit tube MM phono preamp.


Another quality tube MM phono kit from Greek Radi0kit. This time in a Hammond wood cheek chassis and sprayed Indian Red. Also from Radi0kit the PS kit which employs regulated 12V for the filaments and electronically smoothed HT of better than 250V depending on load. 

As with all these kits they sound excellent with the standard JJ 12AX7S tubes. Parts are quality;- ceramic sockets, Visheys, Dale, Nichicon and Cornell Dunbilier. Mantra is dead quiet, looks smart and sounds really great. Happy with the build.

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.