Monday, February 19, 2018

Review: Ortofon Super OM 20 Phono Cartridge

Introduction: Reviewing phono cartridges is a difficult task.  Why?  Because it's part of a complex system involving the tonearm. platter, vibration, setup, and, based on the quality of the other components downstream, can radically one's perception of the whole system.  Also a cartridge that works wonderfully for one system may be dreadful on another.  That's the nature of the analog beast: difficult to tame but, to my ears, worth the trouble.

As for why I decided to replace the Shure M97xE; it's a matter of personal taste.  The M97xE is one smooth cartridge but I had the feeling I was missing something, mostly the very top end sparkle.  And since I'm upgrading my current system - one component at a time - I thought it was time to try something a little different. The OM series was mainly selected because it is supposed to be an ideal match with the lightweight arm on the Dual CS5000 turntable.  The CS5000 originally did ship with an OM cartridge, so why not take the manufacturer's recommendation to heart?

Among the family of Ortofon's OM cartridges I selected the OM 20 - it is affordably priced and, based on my online research, strikes a good balance between detail and listenability.  It's a Moving Magnet cartridge with a healthy 4mV output, which will work perfectly with my soon-to-be-replaced Adcom GFP-555 and my next future preamplifier.

Setup:  Since the Dual CS5000 has a lightweight tonearm, I pulled out the removable 2.5g weight that is inserted on top of the OM20 cartridge.  With the Dual's easy to remove headshell, cartridge swaps are easy; provided you have a pair of good eyes.  I'm definitely due for my first pair of bi-focals so it took a bit of fiddling with the wires, along with some careful tightening of the headship clips.  Once I had the cartridge mounted, I used the protractor that came with the turntable.  The narrow body of the OM 20 cartridge makes alignment easy.  Tracking force was set at 1.2g using my fiddly digital gauge.

Initial Thoughts: After installing the new cartridge I found the sound to be a touch bright and forward.  Lively was the first thought.  Some hotly records vocals were strangely muffled. After adjusting the VTA and double-checking the tracking force, I spun a couple of records that night.  A few days later I felt comfortable enough to start some detailed listening.

Lisa Gerrard of Dead Can Dance has a voice that is both ethereal and powerful.  The Mobile Fidelity pressing of Spiritchaser showcases her vocals wonderfully, as does the Ortofon OM 20.  The notes from that golden throat soar above the primeval music, and roll around, expand, and then come together like I'm under the effects of a psychedelic drug.  This is about as close as one can get to being high without taking an illicit substance.  I've heard this record done a little better on more expensive systems, but not by leaps and bounds.  Nor have I ever heard the Dual CS5000 sound this good.  Sure isn't in VPI Aries 1 territory, and any sins are ones of omission, but I am loving the overall sound coming out of the Wharfedale Denton speakers.  Considering the budget, very impressive.

Bass has depth and impact, while the left-to-right stereo spread go beyond the edges of the speakers.  The real magic is in the midrange - lively, engaging, and with good pace and timing.  The treble is more extended than the old Shure cartridge, but it isn't bright either.  So far so good.  For my next record I picked something a little more down to earth.

I'm not sure if you will find many Outlaw Country fans in audiophile-land, but with Waylon Jenning's Honky Tonk Heroes they're missing out on one humdinger of an album.  This first pressing is pure RCA studios: warm, wonderfully recorded, and just brimming with that old school Nashville production.  Jenning's vocals are rich, and if a system doesn't capture this magic, then you know something is wrong.

Bass: Attack of the deep bass guitar is quick with no overhang.  Warm, dark, and low - like it should be for this era of recording.

Midrange: full-bodied but no excessive warmth.  In comparison the Shure could overdo this portion of the spectrum. The upper midrange of the Ortofon is definitely more lively but still captures the huskiness of Waylon's vocals.

Treble: More extended, lively, but the upper end never becomes aggressive or shrill.  How much of this is the Denton speakers remains to be seen.  In this department the Shure was more rolled-off, and perhaps more pleasing on some hotly recorded albums.  

Other: Channel separation is excellent and every instrument sits in its own space.  I've heard more detail and body with moving-coil cartridges but this moving magnet, at least in this system, is more cohesive.  There is no portion of the frequencies that stick out like a sore thumb.  Depth is also less than the best I've heard.  It's not quite flat-as-a-pancake, but I certainly never got the illusion that the drums were in the next county.

Neil Young's Live at Massey Hall 1971 is an excellent recording that should be part of anyone's collection of good music and good sound.  This is a very system friendly album that sounds great on every stereo I've owned.  This current budget setup was no exception.

The body of the acoustic guitar was about as real as it can get, and so were the vocals.  The effect is similar to sitting mid-row in a small coffee shop.  So a very personal album.  Micro and macro dynamics of the guitar and the piano were fairly realistic, only bettered by the Aries 1 turntable and UREI speakers of yore.  Once again I heard shorter depth and a bit less detail than my older systems, but there was still a cohesiveness that really brought my enjoyment factor to a very high level.

At one time, when I was a much younger man, The Clash was called "The Most Important Rock Band in the World."  If anyone was listening to me, I would have to snub The Clash and go for James.  Their Eno produced Laid is an early example of what makes their albums sound so close to perfection: catchy hooks, memorable lyrics, Tim Booth's powerful vocals, and the ability to bring me near tears with a mix of sadness and elation.

The Ortofon cartridge wrings out the best of the 90s production - deep bass, the sound of the drums, the jangle of the guitars, and the dynamic contrasts.  This is no audiophile hidden gem since it was probably recorded on early digital equipment with plenty of overdubs and even a few effects.  Nonetheless I've never heard this album sound so right.  I had to tap my toes, smile, and remember my youth with wistful melancholy while being uplifted with the wonders of life.

The swelling and rolling of the bass was impressive and was the precision of the midrange.  The treble was never overly aggressive either.  Again there was a slight lack of body and some minor loss of definition compared to more expensive cartridges, but the Ortofon is really no slump in this department.  I'm looking forward to trying out some different phono stages to see if this area can be improved on.  The Adcom, after all, uses op-amps with high negative feedback and currently has some aged components, so perhaps I'm expecting too much out of this budget unit.

Conclusion: With cartridges it is hard to make blanket recommendations, but with the Dual CS5000 and it's lightweight tonearm, the Ortofon OM 20 bests anything else I've tried on this rather modest turntable.  It certainly is more cohesive than the Shure M97xE, an Audio Technica ATN95HE, and even better than the Nagaoka MP-110.  Of course the Ortofon is a bit more expensive than any one of these cartridges, but what is really happening here is a matter of system matching.  And, as a bonus, the Ortofon OM 20 cartridge can take any number of stylus upgrades which will be worth exploring in the future.

As for the sound of the OM 20, it really did exceed my expectations, bumping my rather pedestrian system up another notch in quality.  Considering the odd blend of gear here - vintage American amplification, small British mini-monitors, and a German turntable and cartridge - the sound is cohesive, engaging, and just touching on the fringes of high-end.  I hate to gush since such proclamations are often viewed with distrust, but, at least with this turntable and system, the Ortofon OM 20 is a real winner.  Highly recommended.

Adcom GFP-555 preamplifier
Adcom GFA-545 amplifier
Dual CS5000 turntable with Shure M97xe phono cartridges
Pioneer DVD-V7400 DVD player
Wharfedale Denton 80th Anniversary speakers
Kimber 8PR/4PR bi-wire speaker cables
various budget interconnect cables

Tuesday, February 6, 2018

Review: Wharfedale Denton 80th Anniversary speakers

Introduction: I've been running with B&W Matrix 805 speakers for almost five years now.  They are great speakers but after such a long time I was interested in trying something new.  I first started concentrating on finding some KEFs, which is a speaker brand that I've always liked.  I had my eye on a pair of LS50s, Reference 1s, or even some small Q towers.  Instead I was drawn to a Wharefedale Denton review on the Steve Hoffman forums which had several fellow audio nuts being in love with this speaker.  One of them even sold his KEF LS50s and stayed with the Denton speakers. Given the low price of these I decided they were worth a try.

The Wharfedale Denton is a small mini monitor sporting a 5" Kevlar woofer and a 1" textile dome tweeter, something you would find out of an 1980s speaker.  These particular units, with an original cost of $1000USD, were created for Whardale's 80th anniversary and as a homage to the original vintage version.  Sensitivity is a low 86dB so low-powered amplifiers may have trouble driving them.  The speakers can be bi-wired via the gold binding posts outback.  Bonus - prices have dropped considerably with this speaker, now they can be purchased for $400USD.

I bought my pair of Dentons used so they were already broken in.  The original Wharfedale box arrived quickly and without any damage.  Packing was excellent and the little cloth bags surrounding the speakers was a nice touch.  Build quality appears to be very high.  Rapping on the side of the cabinets gives a high "tink" instead of low, hollow "thunk" which reveals some heavy construction.  The veneer / wood combo and silver grille looks quite presentable in my mid-century modern furnished house.  Very high - at least in this domicile - wife acceptance factor.

After removing the Matrix 805s and associated line-level bass equalizer, I plunked the Wharfedale's on top of the speaker stands.  I then moved the speakers a little further out into the room.  Since I already had some Kimber 8PR/4PR cables in place I decided to bi-wire.  Amplification is the soon-to-be replaced Adcom GFP-555 preamplifier and GFA-545 amplifier while the front end is the Dual CS5000 with the soon-to-replaced Shure M97xe phono cartridge.  As you can tell, I'm in the middle of a system rebuild so stay tuned for further developments.  But right now this is a decent budget system, something that someone who has $400USD to spend on speakers might have.

Listening: Initial thoughts - a little boxed in sounding.  A little flat and very polite.  But these speakers were literally winter cold having sat in a UPS truck and on my doorstep for a few hours before I set them up.  After running some errands, and with a fully warmed up stereo, I finally sat down to do some serious listening.

One of the groups I've been collecting lately is The Police.  I now have all of their albums on Japanese pressed vinyl, but for this session I went with 12" British-pressing single of Wrapped Around Your Finger.  This is a really excellent sounding cut of this song, besting my LP version.  On the Wharfedales the bass had a lot of PRaT, laying down a solid foundation that only increased the enjoyment of this song.  Dynamics, considering the size of the woofer, was impressive.  I've heard similarly sized woofers in KEF and other speakers that get muddled in this part of the spectrum.  Perhaps there is some mid-bass hump here at play but it was still tight and well-done without any overhang.

The all important midrange was clean and lively with a touch of warmth.  Vocals sounded natural as did the other instruments.  Each sat in it's own space without sounding confused.  This made it easier to pick out the different threads of the song.  With the narrow front baffle, the Denton speakers also did a more than fair job at disappearing, only leaving a good left-to-right stereo spread.

The treble on this 12" cut was clean though perhaps a bit rolled-off.  Very British polite, if I do say so myself.  The brashness of the cymbals were muted, though to what degree would require further exploration.  But the first impression was of a very listenable speaker that didn't sound forward or overly bright.  That can be a difficult thing for many small speakers since the temptation for manufacturers is to make a speaker that has a lot of fake detail by having a tipped-up response.

Dan Bejar is the talented singer-songwriter that fronts Destroyer.  Kaputt may be the best realization of his vision: idiosyncratic lyrics mixed with breathless delivery, all held together by a tight multi-instrumented backing band.  It reminds me of the lighter moments of Roxy Music mixed with free form poetry.

On the Denton speakers the music jelled together very nicely, making a cohesive picture that allowed me, to repeat myself, hear the different threads of the song but experience them as a whole.  Bass, once again. was very tuneful.  The midrange was smooth as was the treble.  I also noticed some extra detail retrieval that I hadn't heard before with the Matrix 805s speakers.  With the Dentons there was some synth that was low in the mix, along with extra breathiness in the backup vocals.  I've heard this album many, many times so this extra detail came as a bit of a surprise.  Nor was it hyped up detail from a bright treble, but instead seemed a completely natural part of the song.  Color me impressed.

 It was time to try an album that I am very familiar with, one that I have heard across several systems - a British pressing of Supertramp, Crime of the Century.  The lead in song, School, is bombastic with very deep bass and explosive dynamic contrasts.  How does the Wharfedale hold up compared to my departed UREI 813A speakers, which could really deliver the goods?  In a word (or three), not so well.

The deepest bass here - and there is a lot of it - becomes rather one-note and plodding, missing out on the subtle shadings I hear on much larger speakers.  The same was true with the dynamics which did not have the swell and force it should have had.  This is hardly a surprise given the physics of a 5" woofer; after all there is only so much air that it can move.  An added subwoofer would really help out here.  It really was surprising how nice the bass sounded on the Police cut versus the Supertramp track, showing the physical limitations of the small woofer on some material.

The midrange and treble, however, were still very pleasing but the muddiness of the bass did distract from the overall presentation.  Depth was foreshortened compared to the best I've heard, but the left-to-right stereo spread was marvelous.

A non-audiophile favorite of mine is John Moreland's High on Tulsa Heat.  The simpler tracks, which feature John's emotional voice and guitar, sounded pretty satisfying.  I was reminded of the time I saw him play live at the Ark in Ann Arbor.  The full band songs, however, were dark sounding and lacked air and detail.  I put the blame on the home studio recording equipment and microphones used, but just to be sure I listened to some brighter albums to see if they were noticeably rolled off on the top end.

The Stranger Things Volume 2 soundtrack is nothing but synth music made in a retro-70s style.  The higher frequencies were well-controlled and didn't display any massive roll-offs.  I would expect this to be a tad brighter than what I heard but not by much. 

Next up was The Blue Nile - A Walk Across the Rooftops, which features swooping synths and austere guitar work.  The top end was prominent but a small touch of top end loss was still apparent to these middle-aged ears.  It is obvious that this treble roll-off was an intentional design decision, made to replicate the sound of more vintage speakers.  So the Dentons are not the most accurate of speakers but a flaw that I can live with given the rest of the system budget.

Conclusion: In the sub-$1000USD range, the Dentons are the best that I've heard - period.  Highly recommended.

Life is about compromise, and speakers are among the worst in this regard.  The reality is that when dealing at this price range, it takes a lot of first-class engineering and careful listening to make a speaker work this well.   These are transducers that carry the music in an engrossing, melodic fashion.  Poised is the word that comes to mind, making lesser speakers in this cost bracket sound positively brash and unsophisticated.  The toe-tapping enjoyment I get from the Wharfedales make their sins ones of omission, which though are many, mostly fade into the background.

Limitations?  Many.  These are not party speakers. If you want something that rocks and plays harder, I would suggest you research any number of larger brands and models; especially something with a bigger woofer.   Another option is to add a subwoofer.  If you need even more finesse or bandwidth, then you're looking at spending more money.  The Denton speakers are well-balanced for their size, drivers complement, and price point but there are a lot of possibilities out there for better sound.  We shall be exploring these as my system changes.  But for now I will stick with the Denton speakers and see how they respond with tube amplification and a better phono cartridge.  Stay tuned!

Adcom GFP-555 preamplifier
Adcom GFA-545 amplifier
Dual CS5000 turntable with Shure M97xe phono cartridges
Pioneer DVD-V7400 DVD player
Kimber 8PR/4PR bi-wire speaker cables
various budget interconnect cables

Update: The replacement of the Shure cartridge with an Ortofon Super OM 20 really broadened the bandwidth of the Wharfedale speakers.  Treble no longer sounds rolled off and bass -within mid-dB levels - has a lot more composure.  It's a nice little match.  See the Ortofon review for more details.

Monday, January 29, 2018

Project: IKEA Kallax LP Storage with Feet and Shelf Stops

I have been unhappy with my old blonde Ikea Expedit shelves that have been used for storing LPs. The finish doesn't match any of the new furniture - mostly dark walnut or teak - in the house, so I decided to get something to match my mid century house. A 2-hour trip to Ikea and I buy three new Kallax 2X2 shelves, but opt for the turquoise blue (my wife and I aren't afraid of colors).

First step - assemble the Kallax shelves. Pretty straight forward. They feel a little lighter than the out-of-production Expedit but not by much.

I then cut - by hand - twelve roughly 13" pieces of 1X2 wood that I bought from Lowe's. Screws are 1 and 1/4" long. Wood and screw cost was just over $14.  I'm certainly no carpenter but this part of the shelf won't be seen by anyone.

Next I flip the shelf "upside" down so I can install chrome Ikea Captiva 4" feet which are found in the Kitchen section of Ikea.   An additional foot in the center was added for extra support. Screws come with the legs but I did drill a pilot hole so less work is required to get it in.

Finished piece looks like this:

Now the really hard work - it's time to move some stereo gear, shuffle the old shelves out, remove the protective tape on the Kallax shelves, haul a ton of vinyl, and then bask in the glow of my labors.

The stops work great, making my LP collection look a lot tidier - almost like a magazine shoot. The addition of the feet give more "space" to the end of my living room, which in turn makes the area look larger.

And a final picture of the stereo gear back in place and the records tucked away.

Wednesday, December 20, 2017

Short Take: the Adcom 545

(picture from Google Images)

My old McIntosh MC2100 is in desperate need of a rebuild.  This poor amplifier, after all, is knocking on forty or more years of usage, which means capacitors, resistors, and other bits are due for replacement.  This age has shown up as "vintage" warmth, but also a rolled-off top, plummy bass, and some signal degradation.  To put it bluntly, this amp sounds old and tired.

With that in mind I decided to replace the Mac with a partner to the Adcom GFP-555, the venerable GFA-545.  Of course the 545 is no youngster either, but it is inexpensive and can also be stacked on top of the preamplifier.  Given my tight listening space this was the biggest reason to go this route.

The Adcom GFP-545 is a conservatively rated 2-channel power amplifier making 100WPC.  5-way binding posts, RCA inputs, captive power cord, etc.  Very basic and no frills with only the mentioned connections, an on-off switch and indicators if either channel is clipping.  Designed by Nelson Pass, it sits between two other models, the 60WPC GFA-535 and the 200WPC GFA-545.

In the 80s and even up to the 90s, Adcom amplifiers were mainstays in many, many systems,  My father still has an original 555 running in his downstairs home theater system, so that speaks of some good reliability.  But, like my McIntosh 2100, they are getting to the point where some maintenance is due.

How does it sound?  At least in my budget system, very good.  With the fresh power supply and direct coupling, the Adcom had much better and tighter bass than the McIntosh.  It does lack some of the warmth, but the clarity and detail is higher along with a less grainy presentation.  Top end is extended, perhaps a little etchy compared to the best tube amps, but nothing that will drive the listener out of the room.  So a good basic power amp that can be used in a variety of systems.

Ultimate fidelity?  In a word: no.  But my current system is a whole bunch of compromise, and with the soft presentation of the Shure M97xe / Dual CS5000 combination and the nature of the Adcom GFP-555 preamplifier, it somehow all works, even blunting the forward character of the B&W 805s,

So for now the Adcom 545 delivers music and does it in a way that I find inoffensive.  But with tube amps coming soon it's time in my system is short.

New Project: The Command 1625 Deuce Tube Amplifier

It's been a few years since I've built a DIY amplifier, so I approached this project with some trepidation. With my new house with no dedicated listening room, I went from a multi-kilobuck system to something considerably more down market. But as always, the itch to get back into tubes was too much for me.

So what to build? I'm an audio cheapskate at heart - not because I don't like spending money - but it just irks me to throw down too much money for output tubes. Even the price of an old EH 300B has risen a lot the past few years. So with that in mind I decided to use the 1625, which is a 12V filament version of the venerable 807. Most available 1625s were made during WW2 and used for fighter plane radio sets. There are still scads of them out there and the prices are cheap. I've also used this output tube with another amp and liked the results. So why not use it again?

And for those keeping track, this is the second time I've built an amplifier using the 1625, so I added Deuce to the Command 1625 name.

I know I wanted some power which gives me greater flexibility when it comes time to replace my B&W Matrix 805 speakers. So I decided to do something different and parallel the two output tubes. Guesstimated power output would be 16-20Ws if I run the 1625 in pentode (ok Tetrode!). So I scoured the web for ideas, checked out different schematics and asked a few questions. And I came up with the following design (no schematic yet):

12HG7 pentode driver, parallel 1625 output tubes into a 2500 ohm Hammond 1627SEA, a real beast of an output transformer. No global feedback around the transformer, instead I decided to experiment with plate-to-plate feedback.

Screens for the input and output tubes are regulated via gas tubes. Raw power supply is a simple CLC filter using a 5AR4, large polypropolene capacitors, and a 6H choke.

Off on switch, gain controls and banana jacks for 4-8-16 ohm speakers. Also current meters to see the health of the output tubes since in the past I've had gassy 1625s that went into runaway.

Once I was done with the design, it was time to start gathering parts and figure out top plate dimensions and where to drill the holes. For a clean, non-DIY look I went with Front Panel Express.

Soldering everything together was a matter of patience - and my usual sloppy spaghetti point-to-point wiring. I would only devote an hour or two a day to minimize mistakes. I also ran into some fitment issues that required some uh, judicious modifications.

The first time I turned the amplifier on, I was a nervous wreck. As I said it had been a few years since I built anything. Was I going to get a ton of hum? Distortion? Some problem I couldn't track down? Or worse, a whole bunch of smoke?

Well there was no smoke but I did get some hum and a lot of distortion. And so began some very frustrating troubleshooting. Long story short, plate cap tubes made for radio transmitting like to make a lot of RF. Two tubes in parallel only compounded the issue. I'm no expert HAM radio guy, but the differences between the two output tubes may have caused a tank circuit, or something weird like that. Luckily there was a solution - add carbon composition anode stoppers to the output tubes. Since these are plate cap tubes the resistor and small hand-wound coil will have to be added to the lead. Once I did this the distortion and hum dropped to the point where they were no longer audible.

Now I have to build another monoblock and make some cleaner plate cap leads since I'm no fan of exposed voltage.

Sound? Since with this amp I can only listen through one speaker I can't say much about soundstaging depth. But using an extra DVD player and a single B&W 805, I heard a very clean 'n' clear presentation with a good top-end and good bass control from the 4-ohm tap. Not very "tubey" warm sounding but more neutral than that

Stay tuned for Part 2. where I build the second monoblock, give a schematic, and do some listening tests.