A long road traveled with the McIntosh MC-30

[meagain]

Audible - When the heck are you getting those VRDs anyway? And, are you getting a stock version or having the guts tweeked?

[Audible Nectar]

Meagain,

I will probably take delivery of the VRDs in late April, maybe early May.....not really sure yet, and as I told Craig "no rush" on my pair (he has AK and his stereo amp "launch" in progress), he has been given all the time he needs to take. I have enough on my plate at the moment with MC-30 sampling, and have plans to remove and reinstall the HT roon for spring cleaning, so I'm not really ready for the VRDs yet anyway!!! I'll be picking those up, and have a couple other small things/items to do with Craig, so this will all happen in time....

Of course, those amplifiers will have upgraded caps......Sonic Craft Platinums, in this case. Other than that, just the regular build Craig uses.....and of course, the appropriate accompaniment of tubes....a fair amount of euro-branded old stock tubes.....Amperex smalls, Mullard rectifiers, and outputs to be evaluated and determined later.

[meagain]

Sonic Craft Platinum - Never heard of those before. I'm sending my VRDs to Craig for a checkup after AK and might upgrade the caps as well, tho' unsure which way to go with that at this time.

[Coytee]

Audible... when you planning on your trip to DeWicks? During said trip, you planning (interested?) in hearing the Jubilees? Might I presume Terry is going to get you right on the bench?

[Audible Nectar]

Not sure when I'm going to Terry's. Problem is there is too much on the plate to count on having this done on a "while you wait" basis. I don't want these jobs rushed.....and there is always the possibility that additional parts might be needed. So I'm looking for a way to "one way" these gears down there (AK Pony Express style) and let him do the work (can't trust the usual shipping gorillas), then come down on completion and pick them up. And yeah, when this does finally happen, I would love to hear the Jubilees[]

Meagain - the Sonic Craft Platinum caps are here: http://www.soniccraft.com/sonicap_platinum.htm . About $330ish in parts for the six caps you'll want for this (four .47s and 2 .22s for the total job on two amps). A nice upgrade for these amps, especially if they are seeing the bench anyway.

[meagain]

Oh - It's a sonicap. OK thanks.

[Coytee]

Not sure when I'm going to Terry's. Problem is there is too much on the plate to count on having this done on a "while you wait" basis. I don't want these jobs rushed.....and there is always the possibility that additional parts might be needed. So I'm looking for a way to "one way" these gears down there (AK Pony Express style) and let him do the work (can't trust the usual shipping gorillas), then come down on completion and pick them up. And yeah, when this does finally happen, I would love to hear the Jubilees[]

Too bad you missed Colter driving south. He could have handed them off to me and I'd taken them over. BTW, I'll still do that for you, if you can figure out how to get them to Knoxville.

Another offer for you then... Terry's "office" is about 10 minutes from my work

If you/I can get it (them ?) there... when he's done, I'd be happy to pick them up and take them home so they are out of his way and in an otherwise secure environment. No biggie if you don't want to, just figuring that would thin his collection a bit if you were unable to get there right away.

[Audible Nectar]

Just when you thought this journey was old news.........there's more to tell[]

First, an update on the initial pair: These just get better with time.

The Sonicap Platinum capacitors continue to amaze, of course - but have matured even further over time. The maturation process (or break-in) took about a year - that point where the caps have completely broken in and become as transparent as possible. The hallmark of the SC Platinums IS transparency, and given sufficient operating time do as well as any cap imaginable, with juuuuuuust a hint of warmth to keep things ohhhhhh sooooo smoooooth in the midrange. Soooooo harmonically good and complex.....they have elevated a classic vintage amp into a phenomenal piece of gear, even reacting to cable changes and such that tell the user that these are audiophile grade. For those thinking of using these caps, this build emphasizes the importance of patience and time to allow for the full bloom and liquification of the caps. It is definitely worth waiting for.

So why a fork in the road?

Well, I fell sooooo in love with the MC-30 (and thought this through four steps ahead) that I purchased a consecutive pair of these from a forum member over two years ago, in anticipation of doing another "take" on this amp through differing parts selection. I expected that the Sonicap Platinum caps might be a bit TOO "audiophile", detailed, "high end" - for such a vintage amplifier. While much of my worries have been eased with these builds, there was something ELSE that I was after - an updated, more "vintage" sound that would bring the MC-30 back to what people expect from original amps.

Recording engineer Steve Hoffman has been, in large part, responsible for the resurging popularity of the MC-30 over the last 5 years, being the biggest single fanboy away from this forum regarding this amplifier. It was Steve who convinced music lovers that while the MC275 was BIGGER than the 30, that didn't make it better.....which then took the MC30 out of "bargain" status on the used market, increasing it's resale in line with what the other vintage Macs were selling for. He got me, too[]

Now Steve might not think as much of the Sonicap Platinum builds as I do - they are NOT built for the purpose he uses his MC-30s for. His purpose for the MC-30 is to bring those old, dead sounding recordings back to life. For optimal recordings, he uses other gear. The Sonicapped MC-30s do very well on the good recordings, but SOME of the old stuff just needs a little buttering up - and some added life. Now the Sonicaps do have warmth, but they don't "butter over" an older or less quality recording - those caps are just too accurate. So in addition to my "reference standard" amps (VRDs), the Sonicapped MC-30s do the "audiophile" aspects very well - but do not allow as much for the less-than-optimal recordings that just need a little help. The Sonicaps have that midrange and overall MC-30 warmth, but they DO see the totality of the signal.....

So while the first pair of MC-30s were built more with advices and goals I learned or reinforced via this forum (cleanliness, transparency, micro-detail, and the differences parts make), the mindset for this build was toward the "vintage" purpose that Steve Hoffman looks for in his amps. Since it is not realistic to use NOS caps that are 50 years old, I sought a solution that would mimick that type of sound - something easier....more relaxed. But GOOD parts.

Having two years to use the Sonicapped MC-30s allowed for plenty of time to see what others were up to. Maintaining watch on various forums, a few select choices seemed to surface, most notably the Mundorf Oils and Russian K40, which is a military surplus PIO type capacitor. The K40 is tolerant of high voltages, built like a tank, metal cased, and sealed well, not to mention reviews that seemed to fit the bill - then after consulting with Craig became the cap of choice for this project. We can't go back in time fifty years and get fresh versions of the old caps (wouldn't that be interesting), so we make the best choice we can.

Following Craig's usual and thorough handiwork (essentially the same as the Sonicap build approach Joe used, except with the K40s - and Craig did a helluva build here), I brought the amps home and loaded them with the exact same tube set from my Sonicap amps: Tele smooth 12AX7s, Amperex 12AU7 1960, RCA 12BH7A blackplate 1958, and SED 6L6GC. Therefore, the ONLY change was the caps - right down to the tubes, in an effort to evaluate the cap change only in the best manner possible.

The caps start out a bit "cloudy" and inconsistent for the first few sessions - then they begin to smooth out and clear up with time. Darker and more laid back. As with the first builds, I put a 10 day straight session on these amps to burn 'em in good, and otherwise played them as much as possible. These caps are pretty much what I was expecting....a more relaxed and smoothed out sound, less detailed, more "easy". Yet still some edge....a bit too much "bite" on the rock and roll stuff. I figure the caps may need more time, so I keep "working them".

In an effort to see the whole picture, I start through the parade of CD recordings on the Ah! 4000: The best recordings (lots of Steely Dan and lots of MoFi) sound a bit veiled (as somewhat expected), but I wondered if it was a bit much. Not to worry, I thought, I didn't have them built for that anyway - but I needed to know in any case. So through the lesser quality, older recordings (lots of Stones, Beatles, ZZTop, etc here)....and while it is "in the neighborhood" of what I was looking for, things weren't quite right...not smooth enough, but the tonality is close......OK, that's what tube rolling was meant for, so what can we do here......Steve uses Mullard 12AU7.....

So I roll the 12AU7 to a 1962 shortplate Mullard, allow one hour of warm up time, and VOILA - the sonic picture Steve Hoffman writes about the MC30 is now happening in my living room. SMOOOOOOOOOOOTH, but absent the "fuzz" present with the Amperex 12AU7 - maybe just a bit too detailed of a tube for this setup. SUPERB on the older rock and blues recordings.....and even the too compressed "modern recording techniques" employed on Papa Chubby's "Palace of the King" is in it's "element". That midrange reaches out and GRABS you - just the right amount of "bite" without getting too sharp, yet smooth in the overall to allow for that classic Mac tube sound everyone seems to remember. Midrange life? OH YEAH! Always knew I would have use for the Mullards someday....

Even more notable was how successful the build was for the stated purpose. It's nice to get it right the first try. Credit to Craig on this, as my query about the K40 and my stated intentions had him confirming this in a rather "authority from experience" manner....this was goood....

COMPARISONS..........

OK, so side by side, what's the difference??

These builds only reinforce what I have come to know about this hobby: parts DO matter, and absolutely can and will influence the performance of your gear, especially in a multi stage/cap unit like an MC-30). One might well ask: Isn't one pair of MC-30's enough? Well, probably, but until I got to "playing around" with these did I realize how different a piece of gear can be, even within the context of the still remaining similarities.

The presentation IS different. The Sonicaps are more like "SET", with the detail, clarity, tonal accuracy, and romance of those three lettered amplifiers with the testicles to get out and RUN. Not as good as SET at "microvolume" (that 75ish db dinner music volume SET does like no other), but once you "open them up" a little the MC-30s "do the dance" really well. Not quite SET transparent (because an MC-30 has about 5 stages to go through) but the Sonicap Platinums allow the MC-30 to be as transparent as possible.....and it does make a difference in these amps. The MICRODETAIL here is astounding, particularly things in the background behind a more forward presentation or music layer. Take "Uncle Albert/Admiral Halsey" (Paul McCartney), where about 35 seconds in the thunder and rainfall comes in behind the music....and you can hear every last detail of it. It sounds so REAL, and that's not necessarily the best recording. THOSE kind of details are the rare and expensive kind.

The bass response, while still rounded (tube rectified) is noticeably improved, yet still of the Mac character. What is improved here is the "bottomless" nature of the bass response. Now an MC-30 won't do picture perfect 20 hz square waves on a scope - probably not even at 50....but there is a difference between limited bass response due to circuit limitations vs. limited bass response from bandwidth limited parts. These Sonicap amps present surprisingly tight bass response that is LIQUID. Every other vintage Mac amp I have heard had a sound like the bass was hitting the bottom of something - a fffffttt-THUNK - like a big medicine ball flopping against a piece of plywood - that trademark "whoosh-woody" sound that vintage gear haters point out as unbearable. These don't have that problem. Now you can't go blasting Tool or other such material through them - but the bass is MUCH improved, more of what we vintage Mac lovers like with less bad artifacts. Clear, natural, and rounded.

The "naturalness" of the Sonicap builds cannot be understated. Where they excel the most is where SET excels: Natural instruments where tonality is paramount. The richness in the midrange with the clarity necessary to convey a piano keystroke, the resonance of the bow, the breath of the human voice. The character that is noted through the fullness and richness of ALL of the midrange.....particularly the lower mids, where so many gears leave things bloated or unnaturally thin. When it's right you just go whoa...

The new K40 builds are "the other way" - to emphasize the vintage aspects of the MC-30, what a guy might do if he HAD to rebuild his amps and have them sound like vintage gear would, using caps similar to the era and such. The sound matches the purpose of the build, which is to bring those older vintage recordings back to life in the midrange - which might not be the last word in frequency extremes ANYWAY. Most of those old recordings are ALL about the midrange, as were the monitors and high end speakers of the same era, so if the bass is a bit more fuzzy and the highs are a bit more rubbed off that's OK, because we aren't as concerned about that as we are the tonality and life of the MIDRANGE. So those who love the "warts" of a vintage amp that the audiophiles don't, this is the build for you, and you know who you are. I am some of BOTH. Both have thier purpose and pleasurability. And in this case, the pleasure is to my older rock, blues and jazz.....an amp just for you[]

The commonalities are most notable. For me, first "law" of MC-30 ownership: USE TELEFUNKEN 12AX7 SMOOTHPLATES. EXCLUSIVELY. As Craig would say, "period mark". This didn't matter what build I tried - the Mullards and Amperexes are good - but NO TUBE conveys that midrange in MC-30s like those Teles do. The early Amperexes and Siemens are more extended in the treble, and the Amperexes are more "organic" sounding overall, but there's something about Tele 12AX7s in these amps that they just belong. They should just hard wire 'em in there. Save people the trouble. Same with regard to the 12BH7s - I really like the RCA blackplates, especially smooth for the horns......

The outputs were pedestrian (SED winged C 6L6GC) for all of the commentary here, save for the 200 hour time I spent sampling the GECs in the Sonicap builds (which I'm saving for the time being until I find another quad like mine, and finish all of the "testing" phase of all this). It is notable that I "got away" with using the SED, which really IS a decent current tube. It's reliable and inexpensive, and relatively tough electronically. Guitar guys abuse these on a regular basis and they seem to take it. Only complaint is a bit of upper mid/treble stridency widely reported as an issue with this tube, but yet has an overall tonal balance that is very good for such a "value".

I LIKE the 6L6GC in the MC-30 overall. I think there is a certain "rightness" in the sound of the MC-30 using proper spec (6L6GC) outputs on them. Don't get me wrong - I LOVE the GEC KT66 in the Sonicap builds - they are phenomenal - but I now begin the search for permanent 6L6GC solutions here. I am less enamored with the RCA blackplates in the Sonicap builds....might try them in the K40s to see how it goes. But the rebuilt amps show the difference in the RCA in tonal balance - they seem better suited for guitar (which might serve them better in the PIO). But I'm really beginning to come around to seeking out some GE 6L6GC, as I think they will be optimal in the K40 PIO builds.

And now, the second law of MC-30 ownership: THE 12AU7 is THE second most important tube you will deal with......

The 12AU7, as Steve Hoffman taught me, is the "flavor tube" in these amps. Use Tele 12AX7, flavor with 12AU7. BE AWARE: This is the "phase slitter" tube, which must be strong and balanced. This is where knowing your tubes are tested and obtained by people you trust comes in handy, not only for viability reasons, but because the GOOD 12AU7s cost $$. Now some on various DIY forum areas ditch the 12AU7 ENTIRELY and rewire the amp for other common tubes that are more readily obtainable, in a circuit that might not be so picky. That's fine if you want to use a non-stock circuit. If you want to keep it stock (and I am one of those, at least for now), the lineup of truly good 12AU7 is short, at least in regard to what is possible with these amplifiers. The old adage from Allan is true here - the MC-30s demand good tubes. I like the early Amperex 12AU7 for a more "open" sound (either the D getter or early 60 large O getter are superb). For warmth, the earliest Mullard obtainable.....all are pretty good through 1962. These tubes do place the MC-30s into "command performance" territory.....they are worth seeking out if you want to squeeze the best from these amps.

For someone who would only do ONE pair, what would I do? Can't say for anyone else, but to list the observations here and let you choose. I have found some on DIY forums "mixing" the above caps within the amp to try to get the best of both. I had the luxury of two pairs. I am one who believes that not all amps, tubes, parts and such are equal - and that proper amp and speaker matching is paramount....so I took two pairs and tried to get everything I could ever want out of MC-30s - an amplifier that is a part of audio history that deserves to be preserved. Hopefully the audio gods won't mind our minor intrusions of hi-fi modernity in an attempt to preserve these works of art, all in the service of music. From my own perspective, it's been success beyond what I ever thought possible.

Thanks again to Joe, Craig, and the rest of the crew here who made this slice of audio bliss possible. Without them, this would not be possible. In sharing what I have experienced and learned, it is my hope that this somehow pays it forward by assisting anyone else who wants to know. I hope this little slice of eduMcation was of help.

And then there were four.......[]

[Tarheel]

AN....that was quite a read....very interesting and informative[Y]

[Joe Auwen]

Great write-up Audible!! Now I got to make time to try the 'choked' power supply mod for another comparison...[]

[meagain]

Ouch. I miss my Platinums in my VRDs. It sounded amazing. I want them back.

Audible, do you still have the VRDs? With the Cardas?

[Audible Nectar]

Ouch. I miss my Platinums in my VRDs. It sounded amazing. I want them back. Audible, do you still have the VRDs? With the Cardas?

Oh yeah! Still got 'em. That's another pair of amps that have gotten better with time. I've pretty much settled into thier sound, as those caps have broken in very nicely. Real nice cap - clear and liquid. The VRD's don't need too much help in that department anyway - and the Cardas is a teflon hybrid to boot, so it does a good job getting out of the way after about 500 hours or so. Just a bit "wetter" sounding than the Plats were, I think. Rolling in Amperex 12AX7 and 12AU7 on the front end pretty much "finished" any fiddling I needed to do with those.....they are seriously good, in ways that the MC-30s cannot be....and cover all other desires in 2 channel power amplification that the MC-30s don't cover. The VRD owners got it eeeeeeeasy....

I'm not sure I could live with platinums in my ONLY pair of amps (if I only had one set of amps). They can be a bit too demanding if you don't have other system alternatives. For those who only play the best of recordings.......OK, but if one plays a breadth of quality of recordings (because there's some music that just isn't available any other way), a few degrees "wetter/warmer" can be a good thing if you only have one system.

[Timmikid]

Terriffic write up. It makes me realise how pleased I shouls be (and I am) with my pair. It's also a good feeling to realise that as good as they are now, there are always next steps to take to establish real improvement, which is rare in audio territory. Usually we're talking 100% extra investment, 1% improvement. What a great adventure ahead and luckily not into the great unknown, thanks to this experiment!

Before that (must save a bit still for the next audio investment), I'll be tube rolling again, haven't done that in a while.

Thanks Audible Nectar! [Y]

[Audible Nectar]

The K40 builds are becoming more refined as we go.....more inner details evident, yet with the ease in sonics still desired by the build.