Analogue revived !

diy audio

The future?

The DACmini CX is my new 24bit 192khz source. So far the sound is excellent… all it needs is a little tube love 😉 It may be too tight inside for an all in one source / tube amp, but there is plenty of room to make it into an optocoupler volume control LC 26 tube preamp.


After using the CEntrance DAC for a while I am convinced it is an outstanding value. Not just because of its excellent sound, ability to play 24/192 files via optical or coax and 24/96 files via USB, but because of its stability and isolation from noise. Now it’s time to see just how transparent the Asahi Kasei AK4396 DAC chip really is. Bypass everything and run the balanced DAC output right from the AK chip, into high quality 1:4 step up transformers, then directly to the Hornshoppe Truth buffered preamp. This sounds astonishing! Even better than directly coupling the DAC to the grid of a preamp or driver tube. The dynamics feel decompressed, headroom limitless. It must be the synergy of the interstage transformers being given what they love and the exponential expanding dynamics from the step up transformers creating the most exciting, real and dynamic presentation I have ever heard. Yes, maybe even better than vinyl. 😉 Pictures of the mod follow:

Don’t do this unless you have the steady hand of a surgeon, which is why my solder joints look as poor as they do. Each of those wires is only slightly larger than a human hair. 🙂

The power, USB, optical and coax inputs. On the back is an analog input as well.

The CEntrance DACmini CX has been ‘dechassified’ and wedged into the Hornshoppe Truth chassis. Still plenty of room left for the interstage transformers…

Introducing the True Green DAC. 😉 The final product has all the conveniences of a modern DAC. It is amazingly quiet, has a remote volume control, balance control, and plenty of gain. It is the perfect source for my powerful SMPS GM70 amp.

This post may not seem too interesting, but trust me… you will enjoy listening to this source at Hornfest.

This thing REALLY rocks!

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Inspired by Parker Audio

Over the years I have listened to some very good speakers, and Daves speakers always stuck in my mind as doing things better than most. (Actually, doing less wrong than most) Here is what I have been listening to lately…

I fell in love with these ultra light paper cone vintage drivers made by Grundig. Loose interpretation of the Parker Audio configuration but adding the baffle-less Grundig drivers is what you see here. Other than a single cap protecting the Heil tweeters, the speakers are crossoverless. Flat response is possible by wiring the dipole Grundigs in series which brought down the midrange sensitivity to match the bass output of the single 5ohm Grundig driver in the sealed box, and the 4ohm Heil. Putting the Grundigs back to back in dipole arrangement, along with the Heil tweeters sounds very real. My big JBL horns can’t come close to the presence these speakers have.

Compare my video to your own system… here is the Hi-Rez digital download from Reference Recordings. Free HRx 24/176.4 Music Download And two more HERE.

Randall Rash has a new amp.

Randys custom ampThis was a very special custom amp that I built for Mr. Rash. VT-25 (10) driven by a true grounded cathode 6c45p tube. I still miss listening to it, and the sonic impression it made upon my memory is lasting.

Randy has great ears, and knowing that he hears what I hear made me enthusiastic about this build. This amp was made for him after several conversations dating back to Oct of 2007. We listened to some of his equipment together, and talked about what he values most in audio. Realistic imaging is a weakness in all mass produced equipment, even tube amplification. Randys’ equipment (Zanden, Decware and Vaughn Carina) had a huge wide soundstage, but no depth. To our ears it made piano sound like it was the size of a semi-truck but flat and 2 dimensional. It took me a while to figure out how to control image depth and width, and Randys’ new amp does just that. It is the most accurate imaging amp I have heard. I was very happy to provide this equipment to someone who so appreciates it.

A little exurb from a recent email from Randy…


“…I spent 3 hours last night listening to music ….. wow …..  : ) There is no need to tell you how good the system sounds with the amplifier you designed and built because I am absolutely sure that you already know. I could use all of the worn out superlatives that describe an outstanding piece of equipment, but they honestly would not do this amplifier justice.  The best analogy that I can use is to say that I feel sorry for everyone who does not have this amplifier as part of their audio system.  It allows music to flow into the room in a way that I have never experienced before….”

Thank you Randy, that is just the way I felt about your amp. It brings me joy that you have it now.

Here is a recent schematic of the similar 417A RC VT-25 (10, 10Y, 801A) amp. The main difference is that Randy’s amp uses fixed bias, mercury vapor rectification, and the hot russian 6c45p as a driver.

The photo of Randy’s amp is a link to his website…

Long live diamonds and ditches!

A nice day at Horneshoppe Hornfest

What good could come from that rats-nest of wires? OH, it was an opportunity to try out my prototype source equipment with Jim Dowdy’s $30,000 amplifier. And things did go well, what a fine sound, just a great time! Some new friends, and some new ideas… for even higher fidelity. Ed Schillings’ Hornfest is great fun for young and old! The Hornshoppe horns proved fantastic!

I heart vinyl.

A new tube amp is born…

Everyone likes to watch other people work… maybe you will find this entertaining. Here are some photos of my 210 tube driving another 210 tube, interstage coupled. The schematic is listed on the next page under older entries.

Greenvalve Luddite 2 10 Amp

Have you ever been sitting at home, listening to your stereo and thought “I wonder if this is as good as it gets?” Well, I have. I guess it doesn’t matter much since the idea of what is best is different to every ear. But that hasn’t stopped me from trying! I will say that this is one of the best sounding amps in existence.

Shown below is the schematic of my finest design. Although choke loaded VT-25 driving VT-25 finals is fantastic, it sounds best using the stunning RCA 210 driving another RCA 210. For those who know, they know this is special. This is my gift to you, the DIY guy with great ears.

I have changed the amp to use filament current bias on the input tube, while allowing a choice of driver tubes. The VT-51 (841) tube is a detail monster. If you are into vinyl the 841 driving the 10 is something you’ve just gotta hear!  An added bonus of using the 841 is slightly higher gain, but because of less current draw the B+ ripple is lower. However, my favorite is the schematic shown… a 10 interstage coupled to another 10.

How can I say that this is the best sounding amp in existence? Well, I can not. I haven’t heard them all yet. But compared to every amp I have heard so far
 things look pretty good!

This amp would make a nice front-end for GM70 finals wouldn’t it? 😉

I wish you could hear this amp for yourself. The best I could do is make a few videos of it. They do give a sense of how well the amp images. For your entertainment
 Link to Videos of the Luddite 2 10

The photos below show the amp at various stages of its development. It no longer uses the Mundorf SGO caps for coupling, instead using Hammond 126C 10K:10K interstage transformers.

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