A long road traveled with the McIntosh MC-30

[Audible Nectar]

No worries, Dean.......that extra detail is anticipated, and planned for[]

[Deang]

LOL, I was just kidding Dave. Really, you won't hear any difference at all.

Actually, I'd love to be in the room with you after you get them in. My reaction is always the same -- how can someone say they don't hear this.

[scott0527]

Have you ever seen a nicer looking pair(of 30's that is)?

[Audible Nectar]

LOL, I was just kidding Dave. Really, you won't hear any difference at all.

Actually, I'd love to be in the room with you after you get them in. My reaction is always the same -- how can someone say they don't hear this.

Nahhhh, I just selected those caps because the wrappers looked cool[]

The improvements, even with the BEC's, cannot be overstated though (hey, the PWK formula isn't bad......). Highs showed up where they weren't expected before with these networks (maybe the amps "canceling" each other out in some fashion before?). But if there's one thing I've learned through this whole project is the value of premium parts...they are taking what some in the audio community dub "old school mid-fi" into a truly high end system. These 30s kick even more butt than I ever planned for[] I expect that the new networks will finish the job quite nicely.....should have done that long ago!

Scott - Those amps look very nice..........[Y]

[seti]

Hey guys how about some pics of the work done on these Macs : )

[Chicago_Pete]

I had my 30's rebuilt a couple of years ago with Illinois caps. I really could not tell much of a difference from stock. Switching tubes from RCA 6L6GC's to Mullard EL37's was a pleasant change you may want to try?

[scott0527]

Scott - Those amps look very nice..........[Y]

Thanks Dave, those are Joe's new chassis on there. I'm going to be selling them in January. Too many 30's in the house and have to make room for the upcoming Pcats. They look great but are about 98% stock parts so they'll need a rebuild to sound as good as they look.

[Audible Nectar]

I had my 30's rebuilt a couple of years ago with Illinois caps. I really could not tell much of a difference from stock. Switching tubes from RCA 6L6GC's to Mullard EL37's was a pleasant change you may want to try?

The Illinois capacitors do a good job of "mimicking" a stock sounding/built MC-30. Good way to go if you like how the old macs sound stock. Selection of caps for a rebuild of an MC-30 does influence the outcome as to how you want your amps to sound. I found that I preferred the more modern and resolute caps. Sonicrafts sound good in these if you want a "newer more modern sounding version" - while not hurting the comfortable nature of a Mac. I like to think of these particular MC-30s as "how I would expect an MC-30 to sound if it were reissued."

I'm actually using SED winged C 6L6GC's right now and they sound excellent. One thing I've found out with these builds is that the performance of the more modest tubes is still very good. But the capacitors (at least in my builds) was the key here......best decision I ever made on these was going nutz on the caps.

If there is any tube that I think these amps are ready for, it's KT66.

[Deang]

Chicago Pete needs to change his sig. You might want to ask him what he thinks about the V-caps.

[NOSValves]

I had my 30's rebuilt a couple of years ago with Illinois caps. I really could not tell much of a difference from stock. Switching tubes from RCA 6L6GC's to Mullard EL37's was a pleasant change you may want to try?

The Illinois capacitors do a good job of "mimicking" a stock sounding/built MC-30. Good way to go if you like how the old macs sound stock. Selection of caps for a rebuild of an MC-30 does influence the outcome as to how you want your amps to sound. I found that I preferred the more modern and resolute caps. Sonicrafts sound good in these if you want a "newer more modern sounding version" - while not hurting the comfortable nature of a Mac. I like to think of these particular MC-30s as "how I would expect an MC-30 to sound if it were reissued."

I'm actually using SED winged C 6L6GC's right now and they sound excellent. One thing I've found out with these builds is that the performance of the more modest tubes is still very good. But the capacitors (at least in my builds) was the key here......best decision I ever made on these was going nutz on the caps.

If there is any tube that I think these amps are ready for, it's KT66.

The IC caps do a good job of mimicking the sound of the MC amps original caps after 45 to 50 years of age, deterioration and smearing. Unless someone was around in the late 50's and 60's and have some super audio memory that can snap an audio picture up for comparison then no one knows what the original amps sound like fresh off the line.

Just the physical differences alone make me suspect to the caps sounding anything even remotely similar to what the original caps sounded like fresh in the 50's and 60's. The originals are true film and foil caps the IC's are very inexpensive metalized caps. No way in heck that they perform the same as the originals did when new.

[Chicago_Pete]

Chicago Pete needs to change his sig. You might want to ask him what he thinks about the V-caps.

[Chicago_Pete]

I had my 30's rebuilt a couple of years ago with Illinois caps. I really could not tell much of a difference from stock. Switching tubes from RCA 6L6GC's to Mullard EL37's was a pleasant change you may want to try?

 The Illinois capacitors do a good job of "mimicking" a stock sounding/built MC-30. Good way to go if you like how the old macs sound stock. Selection of caps for a rebuild of an MC-30 does influence the outcome as to how you want your amps to sound. I found that I preferred the more modern and resolute caps. Sonicrafts sound good in these if you want a "newer more modern sounding version" - while not hurting the comfortable nature of a Mac. I like to think of these particular MC-30s as "how I would expect an MC-30 to sound if it were reissued."

I'm actually using SED winged C 6L6GC's right now and they sound excellent. One thing I've found out with these builds is that the performance of the more modest tubes is still very good. But the capacitors (at least in my builds) was the key here......best decision I ever made on these was going nutz on the caps.

If there is any tube that I think these amps are ready for, it's KT66.

 

   The IC caps do a good job of mimicking the sound of the MC amps original caps after 45 to 50 years of age, deterioration and smearing. Unless someone was around in the late 50's and 60's and have some super audio memory that can snap an audio picture up for comparison then no one knows what the original amps sound like fresh off the line.

  Just the physical differences alone make me suspect to the caps sounding anything even remotely similar to what the original caps sounded like fresh in the 50's and 60's. The originals are true film and foil caps the IC's are very inexpensive metalized caps. No way in heck that they perform the same as the originals did when new.

 

                                                                                                         

Craig, so if they didn't sound any better than the 40 year old originals is because they are of poor quality? Guess I have to money up and have them redone again, bummer.

[NOSValves]

Pete,

It's not that the quality is low from a longevity/reliability stand point. It's just that they are not what would be considered a top quality audio grade capacitor. 50 cents to a dollar just doesn't buy much these days in the capacitor world from a Sonic stand point. The caps used in the MC 30's and most vintage gear were not cheap by the standard of that era. Cheap would of been ceramic disc's like used in the cheapest gear of the day EICO for one. Those caps were state of the art for that era. The only thing better was used by the military like Vitamin Q .

If you were to take one of the old caps out of a McIntosh amp and snap it open with some pliers. You will find that the separate film and foil layers are not even separate any longer. The entire contents are now hard as a rock and fused together. No way in heck they perform like they did back in the day. So anything that mimics that now 45 year old sound is doing what?

Craig

[Chicago_Pete]

Pete,

  It's not that the quality is low from a longevity/reliability stand point. It's just that they are not what would be considered a top quality audio grade capacitor. 50 cents to a dollar just doesn't buy much these days in the capacitor world from a Sonic stand point. The caps used in the MC 30's and most vintage gear were not cheap by the standard of that era. Cheap would of been ceramic disc's like used in the cheapest gear of the day EICO for one. Those caps were state of the art for that era. The only thing better was used by the military like Vitamin Q .

 If you were to take one of the old caps out of a McIntosh amp and snap it open with some pliers. You will find that the separate film and foil layers are not even separate any longer. The entire contents are now hard as a rock and fused together. No way in heck they perform like they did back in the day. So anything that mimics that now 45 year old sound is doing what?

                                                                                                                                Craig

                                                                                                           

I bought these IC kits from Vacuum Tube Valley and had a tech do the rehab. Of course this was before I knew about you guys. Anyway, water under the bridge. Want a project Craig?

[Joe Auwen]

Dave,

Great write-up and it does sound (pun intended) like we found a good build for the 30s. I'll get some KT66s together this weekend and get them in the mail for you to try. They will be either GEC Gold Lions or regular GECs, depending on which ones I can get a closely matched quad out of []

Craig,

If it's OK, I'll give you a call this weekend? I've been building the benches in my new shop, so it may be a couple more days before I can start getting a pair ready to send. As soon as I got my woodshop going again Myrl came up with a few projects for me to do when I can fit them in.. [:|]

Thanks for the kind words on the rebuilds...[:$] I started life out as an Aviation Electronics Tech in the Navy (retired in 1996 with 26 years) back when most of the gear we had was vacuum tube. It's been a lot of fun getting back into the 'vintage' equipment... []

[Audible Nectar]

You should consider coming out here, Pete, and have a listen to this pair of amplifiers. If you are looking to have a set of Macs rebuilt, I can tell you from experience that having a chance to listen to a rebuilt pair "focuses the lens" in regards to your confidence with such a rebuild. Once you HEAR them, you'll have a good feel as to whether or not it is how you want your Macs to sound. You can even bring yours as is, and A/B them in same system to make some comparisons.

I'm in the Quad Cities.....three hours west of you (or maybe even less) if you want to have a "look-see".

I'm betting that those KT66 will give MUCH better results in these than they did in prior (stock build) trials.

[NOSValves]

Craig,

If it's OK, I'll give you a call this weekend? I've been building the benches in my new shop, so it may be a couple more days before I can start getting a pair ready to send. As soon as I got my woodshop going again Myrl came up with a few projects for me to do when I can fit them in.. [:|] Thanks for the kind words on the rebuilds...[:$] I started life out as an Aviation Electronics Tech in the Navy (retired in 1996 with 26 years) and it's been a lot of fun getting back into it... []

Sure Joe give me a call.

[NOSValves]

I bought these IC kits from Vacuum Tube Valley and had a tech do the rehab. Of course this was before I knew about you guys. Anyway, water under the bridge. Want a project Craig?

Sure contact me through email and I will get you in line to be done.

[Chicago_Pete]

Thanks for the offer Nectar? I guess I will never get used to using screen names.

Dont see a road trip anytime soon though. I plan on keeping these so I dont have a problem throwing some money into them. My biggest problem would be if they ended up sounding bright. Some people refer to this as detail, to me its listener fatigue big time. I could buy some Adcom or Rotel SS and get those results. If Mac's signiture sound is to roll off the highs, I guess thats what I'm used to. Did that make sense? No offense to the SS camp. Pete

[Audible Nectar]

That's why I encourage you to listen - that will answer your questions. Yes, they do "brighten", because they are using full bandwidth and "true" capacitors made for picky audiophiles, but they most certainly NOT solid state offensive (and also no offense to the SS camp of which I am still a part). What these do is give Mac smoothness AND resoluteness with the "junk" totally absent. If McIntosh were to reissue the MC-30, this is what I would think it should sound like. As Mac would expect, they provide full frequency response - all the way through the top of the spectrum. But it's clean and fluid......and IMO, it's still a Mac. This didn't completely change the amp - just gave it a clean, fresh face that passes the test of low distortion (mandatory for Klipsch) with flying colors. It's still that "Mac kinda comfy"......but CLEAN. If anyone's sensitive to "too wide open", I would qualify......and I don't perceive this build as a problem in that area.

A consideration when rebuilding this amp: You are passing audio signal through about 6 signal caps before it hits paydirt. If those caps aren't GOOD caps, you will lose signal at each stage in a cumulative fashion. I think this makes an amp like the MC30 to be even more "needy" of high grade caps. It repays you for using the good caps. The goal is to allow ALL of the signal through, and let that wonderful sounding transformer and circuit to do it's good work.

I am considering having my second pair of MC-30s built to the "warm" side of things. I'm thinking maybe silver in oil. These Macs discussed above with the Sonicraft Platinums are the "tops off, no restrictions" version (still reasonably warm, but open and true)......but this "consecutive" pair is gonna be made to be "warm and clean".....emphasis on "warm". MC30's are soooooo gooooood, one pair and version just isn't enough[H] They are just dahhhhhhling[8-|] Soooooooo nice on Heritage.......