A Perfect Match ~ Venerable TU-8200R Powers The NanoOnkens Sweetly 19Dec24

I sought the right amp to power the somewhat sensitive (86dB @ 1watt @1meter) NanoOnkens. I've "always" been curious about the Japanese Elekit TU-8200R amp DIY kit. First, the sound at 8 watts is supposedly awesome (though I'd never heard one), but additionally it receives wide accolades from audiophiles on it's clever auto-biasing circuit ~ aiding those wanting to mod & tube roll the amp. So, I built one! It's actually a Christmas gift from Kala, but yeah, I specified, found, and acquired it. There are more modern variants from renowned Mr Fujita but I found a TU-8200R that could accommodate an inboard DAC (also a DIY build) as well, and it was a lot less expensive than his newer stuff. Holy mackerel this is a perfect combination ~ I can fill a big room no problem and the sound is GR8 driving the NanoOnkens full range in free space alone, or when supported by the NanoSub. Woohoo.

Building The 8200R... I mentioned it's DIY. I bought the kit with English instructions, but for $150 less you can still get one direct from Japan without. The build was straightforward and took me 12 hrs or so, on and off. This thing is heavy, solid, and of great build quality; I found only one error in the instructions, and even that is debatable. Howdy there are many screws, but everything registers correctly. Just a few images from the build process...

Firing Up The 8200R With NanoOnkens... I was fortunate to have my build run correctly on initial fire-up! I didn't yet make any capacitor or transformer upgrades as profiled by some DIY audiophiles. I first ran the stock JJ 6L6GC power tubes with the stock JJ ECC82 pre-amp tubes, as these are already pretty nice. Beautiful. But I had a hankering to use that auto-biasing circuit, and the 8200R can support a variety of power tubes, including 6L6GCs, 6505s, KT88s & the series, and EL34 & like... quite a range. And, using jumpers, one can set the amp to run power as pentode, triode or ultra-linear (efficient like pentode but accurate like triode). All my initial measurements are made in triode strapping ~ I could easily get 95dB from the NanoOnkens and I preferred it best, but I may go back and measure other modes. Lastly before impressions and measurements, I stayed with the stock ECC82s throughout, but again, I may well roll through some new pre-amps later.

Listening To And Measuring The Kit... I first listened to 10,000 Maniacs' "From My Tribe" spit from my Onkyo DP1 through the new TU-8200R & the NanoOnkens ~ stellar; then I heard Al Stewart's "Modern Times" ~ heard every instrument. Finally AJ Lee & Blue Summit gave me "City of Glass" and I played Molly Tuttle's & Golden Highway's "City of Gold," I'm a super-fan of these and they both sounded great on the system. The NanoOnkens are amazing, even more so now driven from a high quality tube amp. I took measurements of course and the flatness 80Hz-22KHz is evident. The NanoSub hookup has to be at powered level unfortunately as the 8200R does not have a sub-out at line level. That's not a big deal as the down-converter in my plate amp does not appreciably alter the impedance back to the amp or speakers. I took NanoSub measurements at several crossovers and chose the 110Hz setting and only 35% gain as the best mating to the speakers driven by this amp and wiring the sub as variable. I then also measured the whole integrated NanoKit. My sub placement for measurement is not ideal and I will of course remeasure when I find this kit a home.

Tube Rolling In The TU-8200R... I have two non-stock sets of power tubes for the 8200R of which to listen and measure: a matched pair of Tang-Band 6550s and a matched set of Psvane KT88s. These, like the JJs, are modern manufactured tubes, not NOS tubes. As mentioned, accomodating the new power tubes is just a matter of turning the amp off, letting the current tubes cool sufficiently to pull them, and reinserting the news ones. Surprising to me was that all 3 sets of power tubes measured almost equivalently. The NanoOnkens and the room environment dominate the situation. There is some faster rolloff measured in the highs with the KT88s though. More was apparent in the listening realm. I heard the difference with the KT88s before measuring it; the Psvanes just didn't deliver the vibrancy I'd seek in the high end. These tubes were stock removed from my Willsenton amp that I use to drive the center channel in the NestMT; they were replaced by Mullard EL34s ~ and I will try a pair of those in the 8200R at some point. Too bad I don't like the Psvanes more; they are the best color match to the copper-coned NanoOnkens ~ ok, not too important. If hard pressed to decide between the other two, I'd have to say that the Tang-Band 6550s seem a bit more dynamic than the JJ 6L6GCs, so they'll stay in the sockets for now. I am really pleased beyond expectations with the range, dynamics, and overall sound of the NanoKit driven by the TU-8200R.

Building PS-3249R Onboard DAC... I built the optional "integrated" DAC and installed it in the 8200R. Finishing and installing the DAC was straight-forward. This DAC is not the best I have or have heard but at just $50 for a 16bit/48KHz delta-sigma DAC that travels with the new 8200R, it's awesome. There were plenty of options in the build that I did not strap for, like SPDIF out, external clocking, external power, etc. Those seem primarily for when you want to build a separate box for it.

So, despite its being inside the cabinet, it is not connected to power in there or even the amp board. Power is supplied from the digital source (most often a computer) and the odder part is that its "analog out," via 3 pole mini-DIN is fed to the amp via the source 2 mini-DIN "in" on the amp! Fortunately I had a very short male-male mini-DIN cable perfect for the task. The line out level from the DAC is strong so the amp plays pretty loud without further mods. I streamed some YouTube (Sabrina Carpenter in the pic, but I did rock, bluegrass, and more as well) to test and the DAC is fine... neh good.

I will A-B the onboard DAC against the excellent miniDSP 2x4HD once I retrieve it from Summit. It is 32bit/192KHz and would even allow me to do some DSP on the NanoKit output ~ though that is not very necessary, and I could send the sub just what is necessary at line level. I will also be rolling the pre-amp tubes (which may impact power tube choice as well). So fun, so excellent.

December Music Appreciation ~ Some Deep Dives 16Dec24

Though we're rolling into holiday times, I am not listening to muzak or holiday tunes. This month's MA offer deals out some deep dives into some old and new bands.

Shook Twins ~ I’m very late to the Shook storm. Whatever, I can still offer a stepback. I love the coincident vocals, and then they mod their voices to complicate the show. So cool… mighty skills on audio. Portland, OR trio now ~ gotta find the tour stops.

Shook Twins - Live @ Caffe Lena 15Aug23
Shook Twins on eTown- Talkie Walkie 10APR19
Shook Twins @ Paste NYC - Various 19Aug19
Shook Twins on Audiotree Live - Various 30Sep14

Broken Compass Bluegrass ~ Breaking kids from Chico. Opening/Accompanying the best of NorCal and US bluegrass artists. They are rock stars with some keen covers and originals.

Broken Compass Bluegrass On Yub Trail Trailhead Faires and Lightening 01May24
Broken Compass Bluegrass ft Sierra Hull Luxury Liner 04Jul23
Broken Compass Bluegrass @ SCU/Chico Jack Straw 15Jun23
Broken Compass Bluegrass @ CSU/Chico 22Mar23
Broken Compass Bluegrass @ Off The Rails China Cat Sunflower 04Apr22
Broken Compass Bluegrass @ Green Room New Horizons 18Oct22

Anna Moss/Handmade Moments/AM & The Nightshades/Moss Tones - Introduced just in Moab at the FF this year. I am already a huge Anna Moss fan now. I dove hard on her work, which is deeply outstanding; the Handmade Moments (Anna & Joel) have a cool and at times tragic story. Anna has a killer voice with keen beat box & scat sounds added. When I saw her in Moab she played 6 instruments over 6 songs ~ my sense is that she can do anything musical; so good.

Anna Moss @ OffBeat Sessions In New Orleans (covers Love You Anyway, Penis Envy, Colors) 13Sep24
Handmade Moments in her backyard “Cruisin’” cover 22Nov22
Anna Moss in New Orleans “Don’t Stop Me Now” cover 08Mar22
Handmade Moments in a VW Rabbit in Orleans “High Class Woman” 19Oct22
Anna Moss @ Glasshouse Coffee in Eugene, OR Amnesty 2021
Anna Moss on her NO front stoop for SmallSongs Colors 09May21
Anna Moss in New Orleans “Slow Down Kamikaze” 06Jun21
Rainbow Girls ft Anna Moss “Son Of A Preacher Man” cover 27Apr21
Handmade Moments @ Daytrotter Studios Various 24Aug18
Anna Moss on KVNF Field Productions “Are You That Somebody” cover 28Jan16
Anna Moss in Some Club Somewhere “Ain’t No Sunshine” cover 12Mar15

Building DRC NanoSub & NanoOnkens ~ Custom 2.1 System Yields Huge Sound From Small Boxes 15Nov24-07Dec24

I liked the 5L Elinevan NanoOnkens so much that I decided to get another pair of the Mark Audio Pluvia 7.2HD full range 4" drivers and build another pair, for me this time. The alternative copper colored metallic cones were in stock, so I bought those to distinguish from the originals. I will not repeat the build process here as it is identical to the originals. I had sufficient 15mm Baltic birch leftover from the last build to cover a new pair AND add a subwoofer. The NanoOnkens are just 11"x6.5"x7" and the NanoSub is just 13.5"x9"x12", but they all are pretty heavy. This compact, straightforward, and affordable 2.1 system is completely awesome, with the right amp for the NOs (more on that later).

Suffice it to say that the NanoOnkens are heavily braced, fully lined, restricted port, reasonably efficient (87dB), extended range Onkens that sound great. Pluvia 7 second gen high def drivers are sweet from about 80Hz to 24KHz! They are great "full range" drivers, especially in this cabinet, but also want for low end grunt... hence addition of the NanoSub.

I finished the NanoOnkens in COS so did the measuring and full kit listening there (after 72hrs of break in), driven by the Blodgett Theater Integra Research gear. Here's the 2.1 integrated measurement of the new DRC NanoKit in free space (and the NOs themselves). With sub support the NanoKit is solid from 35Hz to 22KHz! Far below are the discrete measurements of the NanoSub and NanoOnkens that initially gave me excitement for the sub described below crushing its NanoOnken support role and great integration dovetail. There is distortion in the sub but it does not rattle me.

Subwoofer Driver & Design... A key to this 2nd Nano kit is the addition of a custom subwoofer. While I've often preferred sealed subs for their tight musical bass, I didn't want the large driver required to get one down to 40Hz (the low note from a standup acoustic bass). So, I chose the 6.5" Tang Band W6-1139SIF and built a tuned port sub; the sealed box for this driver only went to 62Hz. The TB1139  throws a lot of air with 11.5mm Xmax and wide roll rubber surround. And, with a vented fb of 35Hz, it should cover a standup bass fine.

The challenge of venting to get the 35Hz is the length of the bass port needed. A 5cm (2") port would need to be ~15" long in an cabinet with just a Vbox = 11.45L (derived from Small Thiel parameters), and that is a challenge in a small box. I did the math for a full 3" port but this made the port length ~ 100cm (38.7") ~ I will stick with the 2" port version! I also attempted to design a subwoofer around Onken-like rectangular ports but the cabinet needed to be too big for my use... and I've been there once before and abandoned the build. Finally, an alternative to venting is to employ passive radiators instead. Mating the Tang Band to a like Cms/Vas passive radiator was challenging and ultimately didn't even yield a satisfactory model response curve; I eliminated it too. Here are the modeling compares... I'll lose a little low end using my smallish box, but not much.

When designing a cabinet for bass response, size counts, but I still wanted to keep it "Nano." One also needs to account for volume consumed by any amp, ports, and drivers inside the box. With Vamp = 3.795L, Vdriver = 1.108L, Vport = 3.17² * 𝝿 * 31.4 = .994L ∴ Vspk must be at least .994 + 1.108 + 3.795 + 11.54 internally. But I also needed to assure the height accepts the driver and the port flange; and the depth accepts the driver, the amp, and the port I'll run up between them; and the width accepts the driver or amp. So, ultimately I drew a box which internally is 8.25"x11.25"x13" (WxDxH) that yields and internal volume of 19.8 liters (before subtracting the innards' volumes). I then remodeled "my box" with the final cabinet and 35Hz tuned port (shown above).

Subwoofer Parts... I cut the cabinet material from spare 15mm Baltic birch, and had lots leftover for bracing. I used simple black ABS drain pipe parts for the port but I did get a nicer flanged end for the port to the exterior, and the even interior end, to avoid chuffing. I did have to modify the elbow a bit and ABS glue is messy. Port design was tight inside the smallish cabinet I desired, but I got it done; Lp = 31.4cm. I chose a Dayton Audio 100W class AB plate amp and Precision flanged port pieces.

 

Once I assured the internal fit I disassembled the hardware and glued on the final side. Once dry I'll sand and stain and poly coat before final re-assembly.

I did my usual finishing of sanding, staining in True Black, and coating with 3 layers of polyurethane. Since it's "winter" I did all the finishing inside the warm radiant & water heating closet to assure good curing. I then installed the sub driver, the port, and the amp. The DRC NanoSub came out nice IMO. I might yet "paint" the driver "cone" with some metallic copper design to better mate it to the DRC NanoOnkens.

That's all nice but did it achieve the design objective of righteously covering a standup acoustic bass and integrating with the NanoOnkens well? Yes indeed. After getting a good ~90dB signal from REW to the measurement mic, I set the low pass at several different settings and took measurements. The sub is reasonably flat from 25Hz - 90Hz on its own... very cool. I favored the "orange" low pass cutoff at about 80Hz (clearly the amp continues to pass a signal above that but ok, I understand rolloff). I then checked the integration with NanoOnken measurements in free space just as Eline has them running. GR8 integration. I do hear some chuffing at super-low frequencies below 25Hz, but my material rarely reaches down there. Playing material is different than measuring and the NanoSub is awesome and a perfect compliment to the NanoOnkens.

Now I need to mate the NanoKit with a perfect dac/amp, and find the whole thing a true home. The current temporary home is on the StudyDesk driven by the Topping MX3S.

"Winter" Fishing The PT ~ Plenty @ Nature Center & Valco 04Dec24

Flows are down to ~80cfs; viz is 25"; air temps are ~65°; crowds are modest during the week; fall mayfly and midge hatches mid-morning to mid-PM. I had a decent outing on the PT, 1st at Nature Center, and then at Valco upstream. I caught a 100 tiny trout 6"-10" on everything on the line: mayflies & midges including olive mylar Perdigon, black beauty, pop top, awesome midge, grey & black RS2s, etc. I also caught a couple of 18"er cutbows, one in each section (no pic of #2 as my battery died), and some 15"-16"ers too. Fish were spread out and comfortable but I didn't see the even bigger fish in here. It was a nice day on the water, and it was not too crowded at all.

I was especially excited about the performance of the new Rodfather Ghost Bomber. Of course it handled landing all the fish today on 5.5X but the long line nymph rig casting and mending performance was completely "on."  This has got to be one of the very best rods from a Chinese blank, MHX Native. I can't wait to get some bigger stuff on.

At the Nature Center, above the big weir, I was surprised to see redds formed. I don't know if they are brown trout spawning beds or what. Perhaps the fish are confused or finning off sections early but I did see fish on them! Weird. I didn't fish to them but did catch some decent 'bows nearby... dunno.