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  • More models from the MRHA conference

    2015 - 06.27

    Okay, I’ve got a few more photos worth sharing that show the models that I had been working on to take along to the 2015 Milwaukee Road Historical Association 2015 conference in Yakima.  As seen previously, here is Bipolar E1 in the experimental Olympian Hiawatha paint scheme, this time from a different angle:

    Bipolar E1 in the experimental 1948 Olympian Hiawatha scheme

    And here’s his buddy, the Skytop sleeper/observation car #16 “Gold Creek” in the 1948 paint scheme with gold lettering, additional maroon band and gray roof.  I did a lot of work on this car: decals, dull coats, gloss coats, added stainless fluting to the rear, etched stainless lettering for “Olympian Hiawatha”, painted grabirons, interior partition, window glazing with Lee Filters #730 Liberty Green, and lightly weathered the trucks, which I swapped in from a Walthers car for better looks.

    IMG_7458 v2

    When running around Seattle’s Union Station on the unelectrified tracks, the fellow below would do the pulling: an NW2 switcher.  It’s a custom painted (not by me) Kato shell on a Broadway Limited SW2 frame which has sound and DCC.

    IMG_7426 v2

    Below we have some trailers for TOFC service (Trailer on Flat Car), as they would have looked in 1980, right at the end of the Milwaukee.  I did all decaling with Microscale decals, dull coat, light dirt weathering, and black diesel exhaust.

    IMG_7415 v2

    And one more close-up of Gold Creek.  Check out that stainless lettering.  Sharp!
    IMG_7465 v2

    All aboard for Yakima

    2015 - 06.15

    This week I’m heading to Yakima Washington to take part in the 2015 Milwaukee Road Historical Association conference, which will be focused on the very area where my model railroad is set!  As part of the convention there is a modeling competition, so I decided to polish up a few models and be a part of it.  Here is probably my favorite, Bipolar E1 in the experimental Olympian Hiawatha scheme.  Weathered the trucks with Tamiya desert yellow, black weathering chalk to fill in surface details then wiped off, floquil hi-gloss over the whole body, added wires to the bells, white flags to denote a passenger extra.  I’ll have more photos down the line…..

    Bipolar E1 in the experimental Olympian Hiawatha paint scheme, circa 1948

    Electric Trumpet pedalboard snapshot: 5/22/15

    2015 - 05.31

    Here’s a few more photos to document the transitory pedalboard setup of the month. I’ve continued borrowing pedals from the fantastic service PedalGenie.com and this month I’m enjoying three new ones: 1. The SolidGold FX Apollo Phaser 2. The SolidGold FX Funkzilla envelope filter and 3. The Electro Harmonix Pulsar Tremolo. Here’s an overall shot of the board as she appeared for the 5/15/15 and 5/22/15 sessions:

    The board: 5-22-15 edition
    A few observations about each:

    1. The SolidGold FX Apollo Phaser is a decent-to-good phaser packed with some totally amazing features. What I mean by that is, purely as a phaser, I still prefer the 1970s Maestro Phaser also seen in the overall photo, BUT the Apollo has some super creative ways of applying the phase that I’ve never seen on another phaser. First off, you can connect an expression pedal and use it to control the position of the phase combination. They describe it as an interesting take on the wah, but since a phaser is totally different than an envelope I’m going to say that the similarity ends with the fact that both are controlled by your foot. This was the feature that drew me to the pedal and I will say that it delivered, conceptually, on what I envisioned when I read the description. In use, the expression control seems to be subtle in the context of a full band. Turning up the resonance of the filter makes it cut a bit harder, and it is quite captivating to mess around with. Matter of fact I have held onto this one from PedalGenie for two months to give myself more time to see what plays out with this expression pedal control.

    SolidGoldFX Apollo Phaser

    It took me a while to figure it out, but the expression pedal control is best used slowly, to create a textural metamorphosis rather than quickly, like you’d “waka-chicka” on a wah.  With that approach a ‘bigger’ sound is yielded, one which allows more subtlety to come out.  Surprisingly, in the context of improvisation the feature I find myself reaching for more than the expression pedal control is the randomizer function, which bounces the phase position all over whimsically. This, combined with the tap tempo control allows you to create a rhythmic texture that sounds similar to a step filter. I really like that effect.  The randomizer and the expression control both do a lot to make this pedal something special. I know I am going to miss this one a lot when it’s gone.

    2. The SolidGold FX Funkzilla Envelope Filter–with a name like that, how could it be bad?! It might be the coolest looking pedal I’ve ever seen with the Godzilla graphic and the sparkly purple paint job. It also has expression pedal input although I couldn’t seem to make it do much that felt interesting. Last month I had tried the Voodoo Labs Wahzoo pedal which is a wah, step filter, and autowah all in one. Regretfully the attack range of the autowah on that pedal was simply out of range for what my trumpet produces, and it literally did nothing. So the Funkzilla is the autowah sound I was wishing for! When you play a very fast phrase you can feel it getting slightly behind on its attack but for the most part it keeps up well even through brisk phrases. This sound is a lot of fun.

    The first session I Funkzilla’d (YES!) I had the ‘Zil after the wah pedal which I think was a mistake. On the second one I used it before the wah, which allows me to slowly sculpt the tone without losing the Funkzilla filter attack. So this guy belongs early in the signal chain I think.

    The SolidGoldFX FUNKZILLA.

    One thing I despise about both of these SolidGold FX pedals is the footswitches they use are hard as a rock and click very loudly when you engage them. Even if I was a guitarist and these were on the floor, I think I’d still dislike that. In our recordings you can hear them click on and off loud and clear. Why anyone would prefer this type of a switch, I do not understand. I’m very biased since most of my pedals reside at waist height and I actuate them with my hands, but were I to buy either of these pedals, I think I would open them up and rip out these awful switches to replace them with soft ones.

    3. The Electro Harmonix Pulsar Tremolo is the most complicated tremolo I’ve ever seen. Complexity is a double edged sword of course, and I feel like I’m stumbling through hallways in the vast mansion of what it can truly do. Right away the coolest feature seems to be the fact that this tremolo offers a few rhythmic patterns besides a constant on/off cycle. Those patterns can also be adjusted to have a different attack with the waveform style knob, swapping from a hard-edged square wave to a smoother triangle wave, to the smoothest sine wave setting. There is a ton of variety in here. I’m blown away by the possibilities that it offers but I’m also left wondering how many people ever touch the bottom on this thing. One dangerous aspect of a very complicated pedal is when you’re in the heat of a cool moment and you reach for it, expecting, you know, a tremolo–but instead it’s still set to that weird-ass setting from earlier in the jam that you were playing around with and was cool at the time but is totally out of place now. The Eventide Pitch Factor has burned me a few times in the same way. Awesome pedals, and they do so much, but they demand your attention to really control them.

    The Electro-Harmonix Pulsar Tremolo

    4. The TC Electronic Flashback Delay–I got this pedal as a loaner from PedalGenie and I liked it so much that I had to actually buy one to keep full time. This now makes 3 (yes, three) delay pedals on the board, which is getting a little bit ridiculous, but wow, it has such a tremendously big soundstage when used in stereo that I was instantly hooked to it. Vince (our guitarist) commented on a portion of our jam “that’s quite a trumpetscape”… any pedal that can coin a new word deserves consideration as a permanent member, I think.  Besides it’s giant stereo field which immediately makes it presence known, the Flashback also has a host of varied sounds which each have their own appeal.  I’ve been digging the LoFi mode and the Ping Pong most of all, but the mod has quite a pleasing modulation sound as well.  And the Tone Print setting lets you add in pretty much anything else you can think of using the very comprehensive editor which runs on your PC and transfers new settings over via USB.  That’s a brilliant idea.

    So full-time TrumpetScape™ Technology is now on hand and life is good. Having these extra pedals around is a lot of fun and stimulating.

    TC Electronic Flashback stereo delay modeler.  With my gaffer tape snake proudly carrying all signals in the background.

    Hurrah for New Speakers!

    2015 - 05.02

    The culmination of my most recent loudspeaker construction project is finally here! The JB mk.IV’s are now complete. I spent a good amount of time listening and I’m feeling great about how they turned out. Some digression:

    On the enclosure: I would use Red Oak again, for sure. My nervousness for working with hardwood for the first time was totally misplaced. When cut with my circular saw, it was essentially the same as pine or any other softwood. Only with the router did I get burning of the surface and it was fairly easy to simply sand that away. If I did another pair like this, I’d probably pay extra to go to a lumberyard instead of Lowes though, since I suspect that some of the porosity I saw on the inside of my cuts wouldn’t be there with a higher quality of board. You can only expect so much from a big box store.

    2-in-1 polyurethane/stain; I would use that again. Wipe-on polyurethane was simply too thin though. That’s good for a final finish only but any sanding is going to take it straight back off again. As my final step I used a triple-thick polyurethane that worked well, although I notice that it did irritate my eyes for about 24 hours afterward, and that’s even with a fan blowing the vapors away from me in the garage. Maybe that stuff has to be used strictly outdoors. The end finish came out quite glossy as you can see in the pictures although it’s not a mirror finish since I did eventually reach the point of no longer caring about how perfect they looked, especially with the flaws already noted in my carpentry. I was too anxious to get to the listening!

    On the design: It’s a minimalist design, really. Two driver system with the simplest crossover possible: the -6dB/octave Butterworth filter, which uses only a single capacitor and a single inductor. That’s somewhat of a major feature on these speakers since nearly all popular designs opt for a Linkwitz-Riley filter with the steeper -12dB/octave rolloff that allows the tweeter to be crossed off lower and/or play louder. The values I selected for the components do leave a slight gap: the cap rolls off at 2.65kHz while the inductor rolls off at 2.55kHz.

    crossover components

    With my mastering and EQing experience, I figured a slight dip at 2.6kHz would actually be pleasing to the ear anyway. The major advantage to the Butterworth filter is a linear phase response to the rolloff region–that is to say there will be no phase cancellation or comb filter effects around the crossover frequency, which all of the other crossover designs suffer from in varying severity. Judging by online reviews of the tweeter and its response curve, I should be able to get away with loud volumes at this crossover point since the resonance frequency of the tweeter is 1.1kHz. Both the tweeter and the woofer had very smooth response curves, so the expected character of the system should be quite neutral. As with my brothers speakers I knew right away I wanted to use an L-pad to compensate for the impedance and sensitivity mismatch between the woofer and the tweeter. The L-pad is a fun way to get a lot of different sonic flavors from a single system as well, since it’s essentially an extra tone control for your stereo system. Never again would I build a speaker without one.

    L fully assembled, R in progress

    For the crossover components, I did go a bit higher end since there’s only 4 total parts. German copper foil inductor for that precision midrange and a French polypropylene film cap for that snooty, refined treble. I did not even both mounting these to a PCB, instead screwing in a spare piece of wood to clamp down the heavy inductor, and a glob of silicone to secure the cap. Both are soldered directly to the inside lug of the + binding post to eliminate an extra set of connection points. The opposite end of the copper foil inductor was also attached directly to the woofer binding post, so it actually has no extra internal wiring on the + connection. For the rest of the wires I used 14 AWG solid copper wire that I also employ as the main bus wire on my railroad. It’s the same type of wire an electrician would use to wire light switches and outlets in a house, so very heavy duty. Totally overkill considering the stranded speaker wire which will probably be connecting these to any amp. It is somewhat difficult to work with though, since it’s stiff and fights against every bend. I’m 50/50 on whether I’d use it in another design.

    Philosophically, these units are quite different than the large speakers I built back in high school that are serving in my living room: those are 3-way with a dome mid, powerful low-reachingwoofer, and a complex computer-designed crossover that has like 40 elements in it. Since there are so many possible choices to make with speaker design it’s almost stupid to do the same thing twice but what can I say, I loved the tweeters from my brother’s green speakers so much that I had to use the same model again on these units since I missed their sound. Every speaker I’ve ever done has used cloth dome tweeters since I prefer their gentle timbre over a metal dome or a horn.

    crossover and foam installed, L-pad visible on the inside

    On the sound: I already knew that these tweeters were fantastic so they have been a joy to have back in my life again, so the ScanSpeak midwoofer is really the new player of intrigue for me here. Prior to building my brothers green speakers I had always wondered about the revered ScanSpeak brand and having been blown away by how good their tweets sounded I resolved to use a woofer of theirs as well on my own design.

    Initially my impression was neutral. The effect that a quality midwoofer has on the overall sound is more subtle, compared to the airy, delicate treble of fine tweeters.  Woofers typically do need a break-in period to loosen up and these seem like they needed that more than other drivers I have known… In my initial listening I did listen to “Spotlight” by SPC ECO and while experimenting with the tone controls on my Kenwood, I flipped on the 800Hz presence boost and immediately exclaimed “Oooh! Oh yeah!” after just a few moments of taking in the sound. Since the midwoofer is taking charge of everything from 2.55kHz and below, that’s definitely all his doing. I’ll need to spend some time breaking these in first, then listening to familiar material to give a true appraisal….

    As for the bass, it does not extend very low, but that was an intentional feature of the overall design. These speakers are intended to be paired with a subwoofer, not yet built. Knowing that, I purposely chose a midwoofer that had a high roll off and a good high end. Ideally I would have preferred a closed box but without making it a three-way design I could not find a driver that satisfied me. Everything that would go low enough in a closed box had a poor top-end response, either not reaching far enough or having too rough of a curve for my taste. Perhaps in the future I may experiment with drivers that do have coarse resonances and choppy curves. Like I did mention before, some dips in the response curve can sound pleasing in the right spots.

    response plots JB mk4 both drivers black

    I have superimposed the response/impedance plots of both drivers here; the plot is remarkably smooth for both drivers and with a 1.5×4″ port, an F3 of 80Hz is achievable with this woofer according to the Madisound website. Final enclosure volume is 4.5 liters or 0.16 cubic feet which is fairly small. The intended volume was 4 liters for the port design, but it’s good to go slightly over for internal bracing, components and stuffing; factoring those variables in, we’re probably beneath 4 liters again, but I have read that stuffing makes a box “look” bigger to a woofer. Another point of compromise was the ratio of sizes between front/top/sides. Ideally I would use 1.618, the fabled golden ratio. However the size of the driver faceplates dictated that wasn’t going to be possible, so I ended up with 1.3 and 1.9 instead.

    One other thing I did was to router off a smooth rounded edge on all sides of the front to reduce diffraction of the high end. The tweeter faceplace comes right up to the edge of the front panel though, so a harsh edge was unavoidable there. Curiously, I like the way the treble sounds when standing slightly above the axis of the tweeter so maybe a certain amount of diffraction is good sometimes? Or that could just be the overall directional response of both drivers that I’m hearing or something else entirely, who knows.

    More for my own later reference down the line than anything else, here is a breakdown of the parts:

    10uF Solen PB10 mfd Metalized Polypropylene film fast cap
    0.50mH Goertz CF.5 (16AWG) copper foil inductor
    ScanSpeak discovery D2606/9200 1″ textile dome tweeter
    ScanSpeak discovery 15W/8434G00 5.25″ midwoofer
    Yung 100W 8ohm L-pad
    Goldwood 1.5×4″ flared port
    Lowes Red Oak panel x2, 7.25″ wide
    Generic gold binding posts

    And some further reports as my listening extends into the weeks:

     Moving these speakers from my Kenwood receiver over to my Marantz PM750DC yielded a major difference in the sound.  Maybe it’s a combination of the room and the speaker placement but they have a new life to them near the railroad now.

     Basslines on Donny Hathaway’s rendition of “What’s Going On” come out clear and defined from my Marantz 6100 turntable.  I underestimated the capabilities of these midwoofers on their low end.  Happily thus far I haven’t heard a tune that exposes any bloated notes on basslines.  That’s always a pet peeve for me.  These speakers will really shine with a sub, afterall that’s how they are meant to be paired.  But until that’s built I can be content with what’s here.

     A whole new amount of depth and life appeared on Royksopp’s “Senior” album, one I have not listened to on a great set of speakers intently.

     Found a few new details in familiar recordings: you can hear the snare rattle as the toms are played at the beginning of Steve Miller Band’s “Fly Like an Eagle”.  And there is some kind of percussion instrument I never noticed before despite listening to Seal’s “Dreaming in Metaphors” hundreds of times–a song I used to be all about in high school.

     Something totally unexpected: I often listen with an extra compressor plugin “juicing up” anything being played over the PC, but who knew–with these new speakers I find myself turning the compressor off more and more, just listening to the original audio exactly as it was.  Compressors can often bring out extra details but jeez, these speakers are exposing how a wide dynamic range actually sounds better than a totally squashed signal that has all information crunched into a narrow volume range.  That’s a beautiful realization I did not anticipate.

     Getting a new pair of speakers sure is a great excuse to go back and listen to familiar music you may have listened to over and over at one point in your life…. which takes it all back to what this whole pursuit is really about

    Legit 70’s Firepower: The Marantz HD-770s

    2015 - 04.17

    Marantz HD-770 top-end drivers and L-pad array

    As posted about previously, I had encouraged my drummer to get the Marantz HD-440 speakers, since I have very much enjoyed owning a pair of their big brothers, the HD-770s. The “High Definition Series” speakers have walnut veneer cabinets and were built sometime in the 70s. In the Marantz 25th anniversary catalog (dated 1978) they are for sale as the medium tier product underneath the “Design Series”. For a mid-tier product though, these are extremely nice. And as an aside, that 25th anniversary catalog is a feast for the eyes if you’re into this kind of thing… here is a link to it at HiFiEngine.  You’ll need an account to view it but it is easy to create one… it’s worth the effort to check out that super sweet catalog.

    It’s clear they put some thought into the design of these units. The most attention-grabbing feature for me was the 1″ dome driver, which is labeled as a tweeter. I’d call that a misnomer though, since the overall frequency response is given as 33-22kHz +/- 3dB @ 125W of “program material”. Crossover Frequencies are 750, 2300, 5000Hz so that 1-inch “tweeter” is handling 2.3k-5kHz.  I have always been a big fan of dome midranges for their lifelike sound, especially on anything of an earthy, organic variety like acoustic guitar, piano, or exposed vocals. Dome mids do a great job of putting those things “in the room” with you. Interestingly the HD-770 has a stated efficiency of 90dB which is very high for a speaker depending on a 12″ woofer to handle the low end, since the woofer is almost always the limiting factor on efficiency and high efficiency woofers are relatively rare in larger sizes.

    marantz HD series lineup... HD-770s are 2nd from the left

    From the factory HD series units were supplied with a “Vari-Q damping acoustical plug” which you could insert to tune the port if you wanted to change the bass response. The trade-off was more definition in the 50-75Hz range, at the expense of anything below. My speakers were bought secondhand off Craigslist and did not come with this accessory. I see some on ebay with the mention that the original foam is long gone… a running theme. Like the HD-440s, the woofer foam on the HD-770s also crumbles away with time. In my case the previous owner swapped out the original woofer for a replacement driver instead of re-foaming it. This can easily be spotted by the convex woofer dustcap; the original was concave. Given the apparent attention that the Marantz engineers paid to driver selection, I wish he had re-foamed the original. If an opportunity ever presents itself, I would like to acquire the original driver and restore these to their intended stock configuration, although the replacement is doing just fine for the time being.  After searching a while on eBay that seems like a pipe dream though, since a pair in need of re-foaming recently sold for $227.50.  That says something though–one, the original drivers were good and two, the market of people out there enthusiastic about keeping theirs in prime condition remains hot.  My set is also missing the metal ring which mounts around the largest woofer, which is too bad because it does look cool.

    The HD-770s have a three-section resistor (aka L-pad) control panel on the front which allows you to individually adjust the volume of the super tweeter, dome midrange and cone mid-bass drivers. When I built the green speakers for my brother I definitely learned that L-pads are a tremendous asset to any speaker design. They really allow you to tweak the “voicing” of the sound to whatever suits your liking. It can’t be over-emphasized just how much of an impact this has on the sound. Put it this way: never again would I built another set of speakers without L-pads.

    These units have a really funky grille, which has brown fabric which comes outward at the center. I can’t decide if they look cooler with out without the grille on, so I keep the one closer to the door equipped with the grille to protect it from passing foot traffic and the one near the window exposed so I can enjoy the neat appearance of the drivers. Hopefully these units will last me a long time. They are certainly ready to pump out some serious dB’s but still have a soft touch for nuance at the same time. That’s a real nice combination.

    no grille... ... or yes grille?

    New Infrared Shooting, March 2015

    2015 - 04.12

    Happy to report that I’ve finally gotten out and done some more shooting on my Infrared-converted Canon XTi.  I don’t use this camera near enough so when we planned a camping trip, I knew this was my chance to get some great captures out in nature, where the IR SLR really shines.  Here’s a gallery of my favorites.  Some are color-shifted to appear blue instead of red, a few I left red and one is black’n’white.  Enjoy:

     

    A VHS Dubber’s Dream, and a Stereo Pre-Amp Sleeper: The Yamaha AVC-50

    2015 - 04.11

    Having acquired the KM-209 Kenwood power amp, I knew I needed a pre-amp to power it. Since it would be in the living room hooked up to the cable box, I knew it also needed to have a remote control. I’ve never been super into surround sound, so I figured I’d look for something stereo-only. Naturally I wanted to get something older, hoping for a better build quality than modern products… and I didn’t want to pay much. After spending a decent amount of time searching for untis with those qualities, it became clear the best deal would be a receiver or integrated amp which had pre-amp outputs, since a strict pre-amp is overtly aimed at the hi-fi crowd who will spend money for discretes. Remotes began to appear in the early 80s so I looked there, and ended up zeroing in on the Yamaha Natural Sound series.

    In short I was looking for a sleeper: something with great specifications that got lost in the mountains of A/V choices out there, forgotten by the advances of time and the piling-on of unneeded features. And I think I found it. The AVC-50. It’s got inputs from sun-up to sun-down, it’s stereo-only, has a remote, and a killer set of numbers behind it.

    Yamaha AVC-50

    If used as a pre-amp, the AVC-50 has some astoundingly good specs. Specifically it has a 103dB noise isolation between channels and a Total Harmonic Distortion of 0.005% which is… stupifyingly low. That’s not a typo, there’s really two zeros before the 5 in that. That’s very formidible for any pre-amp, even at a snobbish level of audiophile haughtiness. Yet here it is in this obscure seemingly mid-level Yamaha. Sort of strange.

    As to the sound quality, so far I’m very pleased. Between this and the Kenwood power amp that’s doing the grunt work, I can discern a notable improvement in the quality over the outgoing Aiwa. The AVC-50 needed some de-oxit spray to get rid of the crackling when the main volume control was turned, but that was it. I also like the switched power outlets on the back which feed my tape deck and the power amp. Hearing the relays inside all three of them go CLICK when you turn it on is neato.  One thing I do wish it had is tone controls.  There is no bass/treble control and I do miss that, although the speakers it’s driving are already balanced just about right anyway.  It does have a bunch of functions I’m not in need of though: this thing would be amazing for copying VHS tapes back in the day.  There’s a huge amount of video inputs, you can select any audio source while recording video, and it even has a video enhancing circuit with sharpness control.  If you were copying tapes, this thing would have been stellar.

    You could probably find one of these for about $50 if you were patient and persistent. Me, I paid a little extra at $75 to get this one off eBay which came with the remote (many didn’t) and manuals. Although the pictures didn’t really show me, I had a hunch that if it came with the manuals it was probably well-cared for. Indeed it proved to be, and not only did it come with the manual, it also had the receipt for extended warranty (long since expired) and, most interestingly of all, the promotional literature. Retro advertisements can be pretty entertaining to look at sometimes, so I’ve scanned in several pages of this for any who may be interested. The pictures date it. And there’s a lot of effort put into explaining the capabilities of the unit. It’s a long sell. Something that I haven’t seen for a modern product of equivalent standing. Below are all the interesting pages of the large brochure… Check it out:

    Subtle Improvements to the Home Studio

    2015 - 04.10

    I’ve got a cheap set of MXL 990 and 991 microphones that I’ve been using as room mics and overhead drum mics for all my sessions and they’ve been doing well considering how cheap they are.  A while back I saw on the web that there’s a community of people who are into modifying these mics to punch above their weight.  The simplest mod is a capacitor replacement; three ceramic caps which are part of the audio signal path are swapped out for film caps.  I know my way around a soldering iron so this was a slam dunk for $7 a mic.  A few before and after pics are below with audio results on the way later….

    IMG_7197 BLOGIFIED

    Shown above is the PCB with the three new caps sitting beside it, and there they are installed in the image below, noted by the green arrows.  Not the world’s most beautiful solder joints but they’ll get the job done.

    IMG_7200 BLOGIFIED

    Residual Greatness: The Kenwood KM-209 Power Amp

    2015 - 04.09

    So I spent a bunch of time on Craigslist not long ago helping a friend pick out components for his first “real” stereo and when I started doing this I knew that certainly I would come across something for myself that would prove too good of a deal to resist. Predictably that expectation came true in the form of a Kenwood KM-209 power amp from the 80s that I got for just $50. It’s nothing special to look at but it’s got some significant power: rated at 150W RMS into 8Ω with 0.015% THD–from 5Hz to 200kHz (according to HiFiEngine). That’s more wattage than any sane or reasonable person would ever need. And yet here we are.

    Kenwood KM-209

    For a very long time now I’ve had an old Aiwa receiver that’s been the heart of my living room stereo setup. I bought that receiver at Best Buy in the 90s, back in the era when Aiwa minisystems were the bomb and everyone had to have one of those. I admit, the trademark green source buttons with the active one lit in red both looked cool and was quite functional from across the room as well. But an Aiwa is an Aiwa, even if this was their attempt to break out of the minisystem market and be seen as something more legit in the hi-fi world. The receiver is still working, although some of the EQ and DSP buttons seem to have a mind of their own these days.

    Probably what won me over on this unit was the excellent experience I’ve had listening to the Kenwood KA-8300. And also the performance of the Marantz PM750DC Integrated Amp… The KA-8300 said ‘hey Kenwood was actually pretty serious, way back when’, and the PM750DC said ‘products built shortly after the peak of a manufacturer’s greatness can be a great deal’. 80’s Marantz gear worked out pretty good. Let’s give this Kenwood a go. For $50, I couldn’t pass her up.

    The sound is neutral, as far as I can hear.  It certainly goes plenty loud.  As for the unit itself there’s a glowing red display in the center labeled “Power Indicator” which has LED indicators which light up on either side of it for left and right channels. There’s also a toggle switch which lets you switch between 1x and 0.1x for the meters, which is a key feature for power meters.  Nothing exotic or amazing here, but some very solid numbers for a cheap price!

     

    A Relic of their Apogee: The Kenwood KA-8300

    2015 - 04.06

    The Kenwood KA-8300

    Probably the coolest piece of audio gear I have is this 1975 Kenwood integrated amplifer, the KA-8300. Kenwood’s not typically a brand associated with hi-fi now, but back in the day they built some real beasts. And beastly the ‘8300 is, weighing in at 35 pounds. It looks and feels like Kenwood had something to prove with this unit. Power is 80W RMS per channel into 8Ω with 0.1% THD rated from 20Hz to 40kHz. That power rating, being from ’75, is surely conservative. It can also handle 4Ω or 16Ω speakers too, which is somewhat unusual for this time period. The most obvious distinguishing features of the amp are those sweet-looking meters on the front. Watching these is a pleasurable novelty and has actually taught me a bit about the amount of wattage required for typical listening levels…not much! There is a toggle button which swaps the meter range between 3W and 100W. This switch is almost always left on 3W if you want to see the needles bump at all. That surprised me, just how little power is actually used for most listening.

    The KA-8300 has pre-amp outputs which can be used simultaneously with the speaker outputs if you want. When I bought a power amp off Craigslist those came in handy for testing it out. But maybe the most useful feature on this unit are the turnover controls, which are 3-position levers that affect the frequency of the “bass” and “treble” tone knobs. Having the option to move those frequencies around actually makes quite a difference in the usefulness of the bass/treble knobs since it allows the user to tailor the controls to match the speakers being driven. Similarly, the “Loudness” EQ adjustment (which boosts highs/lows for better listening at quiet volumes) has two settings. When listening on the Marantz HD-770s which have a 12″ woofer, setting #2 definitely sounds better whereas on their little brothers, the Marantz HD-440s, switching to setting #1 gave a better bass sound. Loudness is a nifty little circuit which I do prefer to use when the volume is at a low/normal level.

    Although this model was not Kenwood’s top-of-the-line unit, I believe it was only a rung or two below that. For the extreme collector, there is a rare copper-colored faceplace and a slightly higher wattage unit that was otherwise virtually identical in feature-set to this one. Those amps command a much higher asking price but I felt this one hit the sweet spot of equalization features and power for the dollar.

    The KA-8300 is totally built like a tank. The proof is in the pudding too, since when I bought this unit on eBay from a vintage-electronics restoration shop, the faceplate was in perfect condition. As you can imagine, I was quite disappointed to see that it arrived with a bend on the upper right corner despite the fact that the unit was very well pacakged by being wrapped up with bubble wrap and styrofoam around that. 1/4″ aluminum plate doesn’t bend easily and after attempting with a large pliers and channel locks, I gave up and decided to call it character. What I learned in the process is that it would take a lot of force to bend that faceplate, meaning the unit sustained a pretty good impact and has kept right on ticking, functionally. All the knobs and switches work good and I hope this one should be a centerpiece of my audio collection for the rest of my life. Here’s to many late nights of musical enjoyment…

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