Review: Denon DL-110 high-output moving coil

(picture taken from Google Images)

My previous phono cartridge was a Denon DL-103R, the famed 'upgraded' version of the DL-103.  Mine had been modified with an aluminum body.  Partnered with Cinemag step-up transformers, the DL-103R was a great performer, offering plenty of hi-fi goodies - soundstaging, detail, etc - at a budget price.  It really is an excellent low output moving-coil alternative to the more expensive units out there.

Sadly, the cantilever of my DL-103R was accidentally broken when I moved to my new house - don't ask!  Since this new place is just temporary and has the misfortune of a smaller listening space where I cannot use the UREI 813A speakers, I instead opted to buy the budget DL-110.  Regarding type and specifications, the Denon DL-110 is a high output (1.6mV) moving coil cartridge that can work well into a standard moving magnet phono input.  At 4.8g of weight, it's also very light and with some tonearms may require the use of the included metal plate.

Using the VPI HW19 Mark III table with a Rega RB300 arm, I was immediately taken with this cartridge.  Though it lacks some of the finer points of the modified DL-103R, it still in no slouch.  No immediate shortcoming come to mind, though the midrange is perhaps slightly forward.  Bass detail is also good and treble extension was spot on with minimal aggression or roll-off.  Detail retrieval - hall ambience, trailing edges - aren't exactly on par with the best I've heard, but once again, any sins were of omission.  So all in all, a very good cartridge for the $139 asking price.

I recently purchased a new turntable: a VPI Aries I with a JMW 10.5" tonearm.  Since I only had the Denon DL-110 on hand, I was forced to use this cartridge which had a cost some 20X less than the turntable.  Due to the light weight of the cartridge body, I as forced to add the included metal plate under the headshell.  This was a tricky operation that required much fiddling and curse words.

Even with the upgraded turntable and arm - and much to my surprise - the DL-110 did not fall on its face.  For example, Neil Young's "Live at Massey Hall" never sounded so real.  Soundstaging was deep and wide and the music - much like the real, live thing - came at you instead of hanging out behind the plane of the speakers.  There was a nice shimmer to the slightly forward midrange, while bass was low but still tuneful, giving great response with the small KEF speakers.  Treble was very extended with more detail than the old HW19 table.  I'm sure I would find more faults with the UREI speakers installed, but at least with this system, the sound was much better than anticipated.  Highly recommended for the budget conscious audiophile.!

System
VPI HW19 Mark III with Rega RB300 or VPI Aries with JMW tonearm - both with SDS Power Supply
Denon DL-110
Cardas Quadlink 5C 1M interconnects
Quicksilver preamplifier with Gold Lion 12AX7 re-issues, RCA 12FQ7s, Raytheon black-plate 5814
Cardas Cross 1M interconnects
EICO HF-60 monoblocks with Mullard XF2 EL34s, GE 6SN7GTAs, Genalex CV4085s
Kimber 8PR/4PR 2M bi-wire cable
bi-wired KEF iQ30 with VTI UF29 stands
VTI BL503 equipment rack

New turntable: VPI Aries I

This was an unexpected purchase since recent events have cut back on my audio acquisitions.  But this was one deal that I couldn't pass up.  Featuring a thick MDF plinth, the heavy-duty metal platter from a TNT table, and a JMW 10.5 tonearm, the Aries is one heck of a piece of engineering.

I've always been impressed with the sound of my old HW19 Mark III turntable and though the Aries would only be a minor step up in quality.  But even with the only cartridge I currently have - the Denon DL-110, I heard a major improvement.  With the Aries I the background is quieter and blacker with less of a washy sound.  Bass goes lower and with more impact, while detail and treble quality has also improved.  I obviously need to upgrade the cartridge, so this isn't a real review, but more of a revelation.  I've always distrusted solid plinth turntables, intellectualizing the superiority of suspended designs.  But I guess with enough mass loading, a great tonearm, and a heavy platter, the more "primitive" solid plinth designs can compete.

More later when I've had time to process the changes and have a better cartridge installed.

Rebuilding a pair of Heathkit W-2 tube amplifiers

 The Heathkit W-2M amplifier is a fairly rare beast compared to the more later versions of the Williamson line of amplifiers.  It is also perhaps one of the earliest incarnations of a commercial ultralinear circuit.  The earlier predecessor, the W-1, used 807s connected as triodes, with pretty much the same power supply and driver circuitry.  Of note, it's would be an easy project to convert the W-2 to match the W-1, since the layout and even the output transformers are so similar.

Anyway, for my W-2 rebuild I decided to stick with a retro-modern ethos: keep the same circuit but improve the parts and biasing method.  Since I consider myself a bit of an audio historian, I prefer to hear the amplifier as the designer intended.  If someone wants to tackle an improved Williamson design, I would strongly suggest the Chimera Labs modification which will also reduce distortion, provide cleaner power, and improve square wave performance. 

(right click and open to see more detail)

Power Supply Chassis: The stock power supply is rather anemic with barely enough capacitance to reproduce transients and extended output levels.  In my case, I replaced all of the electrolytics, also increasing the values except for the first bucket since it is attached to the 5V4 rectifier.  I also added bypass resistors to normalize the voltage between the two series capacitors.  Parts required per unit: (2) 22uF/350V capacitors, (2) 150uF/450V capacitors, (4) 470k/2W resistors, capacitor mounting hardware, and nuts & bolts.

(right click and open to see more detail)

Signal Chassis: Once again, new electrolytics, also increasing the values to improve power supply stability.  Potentially leaky paper coupling capacitors were replaced by new film units.  The input capacitor was removed and replaced by a small value (1K) carbon composition grid stopper resistor.  Aged resistors should also be checked to see if they are within specification.  This is especially important for the ones requiring matched pairs.  Parts required per unit: (2) .047uF/400V capacitors, (2) .22uF/600V capacitors, (2) 1K carbon composition resistors, (1) 47uF/450V capacitor with clamp and nuts & bolts, and (1) 22uF / 450V capacitor with two lug terminal strip for mounting.

 (right click and open to see more detail)

Bias Supply: The 1/4" phono test jacks were replaced by easier to use banana jacks and 10 ohm resistors which now allow the output tubes to be balanced by using a multimeter: set the meter to the lowest voltage range and adjust the 100-ohm potentiometer until a reading of zero is found.  This biasing method is pretty much straight from the Heathkit W-5 schematic and is much easier than trying to juggle current meters with the clunky phono jacks.  Parts required per unit: (2) 22uF / 150V capacitor, (2) 10 ohm, .5W resistors, (2) banana female jacks with washers and nut, and one terminal strip.

Miscellaneous: The stock RCA jack can easily be replaced with a modern gold-plated unit.  On the other hand, the single speaker screw terminal strip is a slightly more difficult proposition.  At this time I don't have an easy solution that doesn't require a drill press and new hardware.  For now I suggest using speaker wire with small "vintage" spades, or bare solid-core wire.

Listening results: The stock pair of Heathkit W-2s, even with ancient electrolytic capacitors, were still quite pleasant.  They sounded a little muddled and lacking in power, but still possessing a musical charm that many modern units have a hard time matching.  The excellent Peerless output iron certainly helps.  However, this simple upgrade really helped, making the bass firmer and the dynamics better; all while keeping the golden midrange and easy going treble detail.  With new parts, the W-2s really excel at musicality and now rate among my favorite vintage amplifiers.  At least in my listening situation, I would still give the nod to the Eico HF-60s, but that's due to the higher power and the overall sound of the EL34, which is a tube I prefer over the 6L6GC family.  But for a different listener and a different setup with more efficient speakers, it really would be a matter of personal preference.

Tubes: With the rated 4A filament supply, it is possible for the power transformer to handle an output tube with a little more heft than the 6L6GC.  Since I'm not one to trust vintage iron too far, I probably wouldn't go beyond a KT66 type.  I would be curious to see how a set of Gold Lion re-issue KT66s would stack up against the vintage Tungsol 5881s.  Another option for the cheapskate would be to rewire the output sockets to use the 6AR6 which is still cheap and plentiful.

With two 6SN7s handling gain and phase-splitting duties, there is a vast world of tube-rolling opportunities here.  For now, I'm sticking with GE 6SN7GTAs since they are easy to get and sound great for the dollar. 

The 5V4 rectifier can be replaced with the 5AR4 which will slightly bump up the voltage and offer some of that classic Mullard sound.  However, with the high price of good vintage versions, one may want to stick with the more common 5V4 with all the various manufacturers and versions.

Conclusion: Bringing an old tube amplifier back to life and ready for another twenty (or more) years of service is always a feeling of accomplishment.  The Heathkits aren't the easiest to rebuild, not with some of the strange capacitor can sizes and small interior chassis depth, but the time and work was worth the effort.  These are wonderful amplifiers with that vintage smoothness but still modern enough for electronic music and pop.  Highly recommended.

New Project: a SE 6CB5A amplifier

After the completion of my 1625 "Command" amplifier, I began to cast my eye around for another project.  This time I wanted to yet again tackle a triode amplifier, perhaps doing a push-pull 2A3/6B4G type.  However, the pesky cheapskate that lives inside my head just couldn't spend that sort of coin on a set of output tubes.  While searching around, I read a thread on diyaudio that lead me to this blog post on Vinylsavor.  Check it out for the signal schematic.

The 6CB5A is a 1950s television sweep tube that wasn't designed specifically for audio, but the curve traces in triode mode are quite good.  This cheap tube can also produce 6-8Ws in single-ended, which is pretty close to the mojo of a 300B.  I also liked the idea of using the 6N7 driver, thought I opted to not implement the expensive interstage transformer, and instead went with RC-coupling.  Hey, this is a budget build after all.

Output and power iron will be from Edcor - I really liked the quality of sound I got from them in the 1625 amplifier.  Chokes will be from Triad and the rest of the parts will be standard bog stuff you can get from Mouser, Allied, and Digikey.  I've also opted for some current meters to monitor the health of the output tubes.

Since a single 6CB5A takes a mighty 2.5A @ 6.3V to light up, I had to purchase a separate filament transformer to power the 6N7 tubes.  Other than that, this is a pretty standard power supply with a fake dual-mono separation for the two channels.

Output iron has been ordered.  Everything but the top plate metalwork has already arrived, so I will provide another post when all the parts have come in and everything has been wired together.  I'm quite curious to hear what this amplifier sounds like since the build/design approach is much different than the 1625 amplifier.  The 6CB5A amplifier will have no negative feedback, a pure triode amplification chain, and minimal parts.  In my experience this should lead to a big sound with a slightly underdamped bass.  Stay tuned to find out!

New Project: Heathkit W4-AM rebuild

I didn't even get a chance to buy another Heathkit W-2, when I saw this golden beauty on Ebay.  A few bids later and I won.  Now the Heathkit W4-AM isn't exactly their best product.  There have been several complaints about the quality of the output transformer, stability issues, and the "lower rent" build quality.  Personally I think it's a lovely little amplifier and worth the time for a good restore.

The first thing to do is to replace the power supply and coupling capacitors.  After that, I plan on doing the bricktop mod to increase stability and improve the quality of the square waves.  And of course I have to score another one so I can listen to stereo.  But even with one amplifier running, I like what I'm hearing out of a completely stock unit.  I also dig the use of all octal tubes and wonder how some Gold Lion KT66 reissues would sound in there - the 4A filament supply should be able to handle the extra load.