PRCarter's Oswalds Mill 2006 Photos

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Apologies for the quality of the photos below - they are raw, full resolution from my circa 2000 Olympus digital camera and run about 350k each. I didn't really have much time to take pictures on Saturday, so these were mostly shot on Sunday morning. You are welcome to make copies of these and re-work them for other uses, maybe you can give me a credit if the result is decent...

Thanks to everyone for a great weekend and conversations - If you have any corrections or questions, send me a note at

(BTW, this folder/index is marked with a robots-no metatag, it should not show up in a Google search - don't lose the link!)

2006_mill_stage_P1010013.jpg

Left to right: Oswalds Mill 'house' RCA horn array speakers (Ubangi basshorns, multicell mids with RCA 1428 field coil drivers, AH! conical horn with another 1428 for high-mids, Fostex horn tweeter for highs...

Brown cabinets are legendary RCA LC1141 single driver speakers brought by Hans Dietze (retired RCA engineer)

Tall glowing rack contains the 'house' RCA 1940's PP 845 theater amplifier with 300B driver amp at top of cabinet

Black rack at center is the house linestage, phono stage, TEAC CD player (Vintage Technics SP-10 turntable in window)

Table with Jeffrey Jackson's giant 304tl amplifier

On floor is another of Jeffrey's DHT preamps (Experience Music) - using 71a tubes driving into a transformer volume control at output

2006_mill_270_sunday_am_collage.jpg: Paste-up panorama of the main mill room - 1MB

2006_mill_discussion_P1010027.jpg: From bottom: Steve Killian with coffee (NC), Steve Scholl (PA), Dave Cigna (Upstate NY), Adam Israel (Cleveland, OH) looking away

2006_mill_preamps_P1010012.jpg: Preamps on the floor - Steve Killian's Lefty on left, Randy Carter's breadboard 'Not-so-matic' preamp on right. The 'Not-so-matic' was built to try different tubes with switchable filament supplies and replaceable signal sections for different tube bases (globe 27 tubes were used for listening at the mill)

2006_mill_douglas_P1010011.jpg: Douglas Piccard (Dearborn, MI) brought this 12B4 linestage and 1269 pentode (thoriated tungsten filament 807) amplifier, and another 'junk project' preamp as well (sorry, not shown)

2006_mill_basshorn_P1010010.jpg: Plywood basshorn for Cogent bass compression driver

2006_mill_lefty_killian_P1010040.jpg: Steve Killian's 1LE3 DHT 'Lefty' linestage with battery filaments (one D cell per tube will run 1LE3 filament for about a month), transformer volume controls, choke loaded with transformer output and gas tube regulation on the B+!

2006_mill_discussion_P1010028.jpg: Jack Roberts (Coastal SC) and Steve Killian (NC) discuss the finer points of cathode bias with DHTs

2006_mill_house_845_P1010020.jpg: Oswalds Mill 'house' system closeup; 300B amplifier to drive PP 845 theater amps

2006_mill_house_845_P1010022.jpg: Oswalds Mill 'house' system closeup; PP 845 theater amps

2006_mill_jj_304tl_P1010009.jpg: Jeffrey Jackson (Memphis, TN), AKA Experience Music, brought this mutant breadboard 304tl amplifier, a whole table-full of thoriated tungsten goodness... 304tls glowing - careful, those plate caps are high voltage with lots of current - no touching! (as Steve Blair said "We'll be sorry, you'll be dead!")

2006_mill_jj_304tl_P1010015.jpg: ...the B+ end - note variacs on each stage, Yoda totem on giant filter choke

2006_mill_jj_304tl_P1010016.jpg: ...and the other end, not sure what all this little stuff does

2006_mill_jj_304tl_P1010018.jpg: ...closeup of 304tl - why yes, those plates *are* glowing orange

2006_mill_jj_304tl_P1010019.jpg: ...closeup of 866 mercury vapor high voltage rectifiers

2006_mill_jj_304tl_P1010024.jpg: ...Eimac 15E thoriated tungsten driver tubes - cute! - don't touch these either!

2006_mill_jj_304tl_P1010026.jpg: ...yet another angle of the 304tl a-glowing

2006_mill_jj_304tl_P1010025.jpg: ...artsy depth-of-field attempt with 304tl in blurry foreground

2006_mill_P1010031.jpg: ...outside the mill

The Presenters, in no particular order:

Hans Dietze, PA
RCA LC1411 cabinets with 15 inch dual concentric drivers - one MI 11411 prototype driver (Hans was the developer for RCA) and one LC11411-c production driver - crazy good sound.

Doug Piccard, Dearborn MI
12B4 Active Load (tube constant current source) linestage
Push-Pull 1269 amplifier
'Junk' linestage in recycled rack mount

Adam Israel, Cleveland OH
Experience Music 71a DHT linestage with transformer volume controls
'Dowdy Lama' GM70 amplifier

Steve Killian, Lincolnton NC
'Lefty' 1LE3 DHT linestage

Jeffrey Jackson, Memphis TN
Experience Music
304tl transmitting tube breadboard

Randy Carter, Charlotte NC (that's me!)
'Not-so-matic' convertible linestage breadboard with choke loaded globe 27 tubes and Altec 15095 mic transformers as parafeed output iron.

Jack Roberts, somewhere in coastal SC
6BL7 SE amplifier (octal TV tube)
6EB7 SE amplifier (another octal TV tube) with high-pass contouring for biamped setup

Larry Dobbins, King of Prussia PA
50W point to point chip amp

Herbert Jaschke, NJ
Dual 300B integrated amplifiers
Pipe speakers, wedge TLs with dual 1354 fullrange drivers and a paper tweeter

Frank C, Central NJ
Western Electric 753c Speakers (713a compression driver, 32 horn, Jensen 15 inch woofer)

Bill Wood, Canada
AH! conical horns
Measuring everything in sight...

Joe Perucki, NJ
56 Preamp/driver amplifier for 45 amplifier

Miscellaneous:
RCA SL12 speakers in attic system, driven by 20 watt RCA PPP 6V6 amplifiers (no shoes allowed in the attic!)
RCA 64a Olson-designed back loaded horn with RCA field coil dynamic driver
Steve Blair (Asheville, NC) brought a pair of early-production Goto 555 alnico compression drivers and cast alloy horns

Other Attendees:
Rick 'Joisey' Henthorn, Blacksburg VA
Ken Lochridge, Greenville SC
Walter Clay, Northern MA
Dave Slagle, Hudson Valley NY
Dave Cigna, Upstate NY
Jim Dowdy, 'Dowdy Lama', Asheville NC
Steve Schell, Cogent, California
Rich Dreysdale, Cogent
Doug Eisenman, PA

The Tastings, in approximate order:

1
Experience Music 71a DHT linestage
'Dowdy Lama' GM70 amplifer
House RCA horn speakers
Flavor: robust, but with clear sub-tones and immediacy

2
Doug Piccard's 12B4 linestage
PP 1269 pentode amplifier
RCA LC1141 dual concentric speakers
Flavor: brighter, sharper, a lot of drive

3
RCA PPP 6V6 monoblock amplifiers
Western Electric 753C speakers
Flavor: sorry to say, I missed this tasting

4
Herbert Jaschke integrated 300B amplifier
Jaschke pipe speakers
Flavor: excellent balance and poise

5
Steve Killian's 'Lefty' 1LE3 DHT linestage
Jack Roberts' 6BL7 SE amplifier
RCA LC1141 dual concentric speakers
Flavor: clear and quick, firm bass

6
Randy Carter's 'Not-so-matic' globe 27 linestage
Larry Dobbins' Chip amplifier (eeek, solid state!)
RCA LC1141 dual concentric speakers
Flavor: some miss-match between amp and speakers - too much damping?

7
Joe Perucki's 56 linestage
With ?
Time to get a beer... sorry Joe, it's not your linestage, it's just too much walking around...

8
Cogent bass fieldcoil in plywood straight basshorn
Flavor: surprising nice midrange without low-pass

9
Jeffrey Jackson's monster 304tl breadboard
Honestly, it all started to blur together after this...

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