04 March 2001
This is NOT a Virtual Visit. I knew I was going to be in New York during the first week of March and wrote to Jeremy in order to arrange a meeting during my stay. He accepted and invited me to his place on Sunday morning. Jeremy and I only knew each other through the mail list called JOENET. Joenet (also called JoeList) is an email reflector list which facilitates discussion of DIY (do-it-yourself) audio topics. The list was started by Joe Roberts, the man behind Sound Practices magazine. In fact there are other members of Joenet mail group who appear on this web site (chronogically): Dave Slagle, Bert Doppenberg, Hugh R. Dean, Roscoe Primrose, Jean-Michel Le Cleac'h, Thorsten Loesch.
It is so much fun to meet a virtual friend in person. Especially when you share the same passion. We both enjoyed the few hours we spent together listening to music, discussing audio, schematics and of course mostly Jeremy's system.
Looking at the size of the speakers and the very limited power of the amp (1.5W/channel), I thought I was going to hear a relatively small sound slightly on the lean side. Well, I was totally wrong (hearing is believing): the sound had an amazing bass extention (for its size) and control, mids were very natural, detailed and airy, treble was extended, natural and devoid of any kind of tiring harshness. The music was so much alive and liquid. Truly unbelievable!
I will now leave it to Jeremy to talk about his own system that he himself built (with the exception of the CD player and tuner).
"I think I will start from the back to
the front. The speakers are folded Voigt pipes, which is a sort of hybrid
TL/back horn. They are two-ways, and I have installed a silk dome tweeter
on top with a simple inline capacitor as the only crossover element, the
idea being to make the load as simple and tube-friendly as possible. The
main driver is a Radio Shack 40-1354 fullrange with whizzer cone, 8 ohm
impedance, which does a good job with most of the frequency spectrum. I
first heard a similar speaker (with a another driver) built by Roscoe Primrose,
another featured friend on your web site. His were so good and so ridiculously
cheap that I soon copied them. After trying them for a few months and learning
some things about these folded pipes, I gave them to my brother and made
the set you heard. By the time I built the second set, I had heard and
liked this 40-1354 driver in Herbert Jeschke's tall Voigt pipe, and so
I approximated his design, except in a folded cabinet to save space. There
is some good information shared among the members of the Full Range Driver
Forum and I include the
Speaker cables are CAT-5 network cable, two runs per speaker, which contain 4 twisted pairs each of teflon-insulated solid core copper wire. I connect all the solid-colored conductors to the positive and all the striped conductors to the negative.
While I am on the subject of cables, for line level I use braided Kynar-insulated wire wrap wire, 30-ga., very simple and pretty good. I have heard some DIY silver interconnects that are much better, I will probably build a few sets of those. I am fortunate that my house seems to be a relatively clean RFI/EMI environment, strict shielding does not seem to be required as it is for other environments. Of course, I probably should enclose my RIAA preamp!
The power amplifier you heard is a DC-coupled "Double Darling" amplifier using 2 x 1626 indirectly heated triodes per channel, parallel single-ended, and a 8532 driver which is loaded by a choke and direct-coupled to the output stage. This amp is similar in approach to a 2A3 amp I built and called the "Free Lunch," however this one is not quite as good - the 2A3 "Free Lunch" has more extended bandwidth and better dynamics. The amp you heard is perhaps 1.5 watts per channel, and its prime virtues are a sweet tone and good dynamics within their limits.
There is a volume-control autotransformer feeding the power amp, this is of the type for in-wall home installations, it is an experiment in using transformer volume control rather than resistors. So far, I like it, although the steps are pretty coarse. It was extremely cheap, less than 30 dollars.
The preamp is a single stage using the Russian 6C45Pi tube, with input grid chokes and output transformer. I am using a small guitar amplifier output transformer, roughly 5K:8 and this gives me an extremely low output impedance with which to drive the autotransformer while stepping down the large gain of the 6C45Pi (about 25:1 step-down.) I would like to experiment with a 12B4 line stage and a closer step-down ratio, say 2.9:1 (5K:600) like the one used in your preamp. I think the transformer I am using now is only of medium quality and can be improved upon. I think I hear the bandwidth limits in this part - I should have demonstrated the RIAA straight into the power amp for you, it sounds very different.
The CD and tuner run into this preamp, the CD is an inexpensive SONY 5-CD carousel, the tuner is a good old ONKYO analog-tuned unit which I have had for quite a while - I rarely use it, but my wife likes being able to let the radio DJ's pick the music for her sometimes. I already like the sound from this tuner - but I wonder what kind of tweaks it might like?
The LP source has a tube RIAA preamp which
I worked out in collaboration with Bob Danielak. It is based on his Octal
Phono Preamp found on his website, and uses 6SN7 and 6SL7 with a single,
simple shunt-regulated supply using gas regulator tubes. Bob has been very
helpful to me as I learn about this hobby - he is technically *very* astute
and has cheerfully participated whenever I come up with ways to "improve"
his designs. Most people would have told me, "I designed it that way for
a reason!" but he has always explored the pros and cons of different ideas
I have raised, and he has
The turntable is also homemade, using the
bearing and platter of the Teres group project, and a Maxon DC motor with
a very clever contol unit designed by Manfred Huber which is quite wonderful.
I use a belt made from a spliced loop of 1/4" magnetic audio tape. The
tonearm is an air-bearing linear
I can't finish up without some comments
about "software": the food you feed your ears is without a doubt the thing
that matters most. Without music, there is no point to any of this, and
it was as an avid music fan and collector that I came to the audio side
of this hobby. I try not to lose sight of which is the cart and which is
the horse, and I try to appreciate the music and not the system. My goal
with building gear is always to enjoy the music and to have it come through
as emotionally and purely as possible.
I try to broaden my musical preferences
wherever I can, it was curiousity about music that got me into this, after
all. I have long been a big fan of some rock performers like the Rolling
Stones, Elvis Costello, and the Talking Heads, but these are not really
artists I would recommend for their
A strong preference of mine is for the 50's Chess label artists, especially Muddy Waters, Bo Diddley, Chuck Berry, and Howlin' Wolf. Though their records are very unnatural sounding (distortion! slap-echo!) good reproduction of this powerful Chicago sound is an important task for any system I'd call mine. The Chess Box reissue series is absolutely essential listening in my opinion.
I listen to a fair amount of 50's Blue
Note-era jazz, I like Sonny Rollins, Miles Davis, John Coltrane, Cannonball
and Nat Adderley, and Thelonious Monk. The Fantasy Jazz family of labels
has put out a simply amazing series of reissues on LP - not all are sonically
notable but many are musically
Joe Henderson has made some great jazz albums more recently - "Lush Life" being a highlight. Discs featuring piano (solo and trio) are also a habit of mine, I especially like many of Bill Evans' CD's and LPs, Duke Ellington's "Money Jungle" and the Mosaic boxed sets by Bud Powell and Herbie Nichols. I'm also very partial to Teddy Wilson's work backing Billie Holiday. Other jazz vocalists I like are Sarah Vaughn and Shirley Horn.
I am still in the learning stages with regard to classical music. I buy tons of cheap LP's from secondhand stores these days in order to educate my ear and my taste. So far the best thing I have come up with this way has been the Chigi Quintet's recording of the Brahms Piano Quintet in F Minor (Op. 34) on Decca (also London.) This disc really moves me.
A couple of lesser-known CDs I'd like to recommend, which I often use as system checks:
Bob Danielak's Audio Web Page:
The Full Range Driver Forum:
Tim Reese's Joelist Information Page:
Mick Maloney's Phono Preamp Info:
The Poul Ladegaard Tonearm:
The Teres Turntable Project:
The Phonogram discussion list for vinyl lovers is a great resource, email firstname.lastname@example.org for details on how to join.
Jeremy's comments about his System:
AA: "Jeremy, how would you describe your system's sound?"
JE: "I have always been working towards a relaxing, natural, liquid sort of a sound, I prefer sweetness to "slam" or "speed." Openness and clean imaging performance are important to me. This system does well on this basis. I have another power amp which was out on loan when Adnan visited, which uses 2A3 output tubes and to my ears outperforms the 1626 amp in every way - it is more dynamic, more detailed, and has better bandwidth. But you'll have to take my word for it. One of my goals has been to have nothing but tubes from input to output, and since getting this done (on the LP source at least) I have been glad I pushed to do this, it really helps the sound."
AA: "Do you think there is room for improvement?"
JE: "I would say I'd like better extension down to the very low frequencies, with more fow frequency power. I'd also like more consistent performance - there are some times when the system sounds better than other times. And lower noise floor - it's not that I actually hear objectionable noise listening to the system, it's just that cleaning things up always reveals better detail."
AA: "Have you got plans for upgrading?"
JE: "Definitely. The turntable is only a promising prototype - I expect to be able to improve its performance further by improving the base and stand. The line stage is sort of a sketch of an idea rather than a finished product, I am surprised it sounds as good as it does. But removing it exposes flaws I would like to correct. With regard to consistency of performance, I think there are both AC power issues and issues with layout and construction. I am getting a little bit of inconsistency in my phono tracking from the way the phono cables are attached, I need to find a better solution to this too. I will probably either return to the Grado MCZ cartridge, with a new stylus, or perhaps use a Denon 103D and increase my phono gain to suit the MC cartridge output. I have a schematic and most of the parts for an OZLoesch Tube/JFET hybrid phono preamp that will probably be fun to try out, and I also have most of the parts to build a 2A3 push-pull amp. I am experimenting with an archaic phase splitting scheme from the '30's for this amp, I am again curuious to hear how this will sound. I think a properly built DHT push-pull amp will probably sound very different from the usual pentode PP amps.
Some of these ideas aren't necessarily intended as "upgrades" per se - I am also just looking to hear how different circuits and implementations sound different.
My gear is always in flux these days because I am still learning how to get the sound I like. I'm at the point in this hobby where I have a long list of things I would like to listen to and evaluate. But DIY is quite a bit cheaper than buying stuff if you like to experiment! The limiting factor really becomes the time spent."