Replacement tubes for Mc C2500 & MC2301 (and a spare MC275)
 

I've owned my McIntosh C2500 preamp and MC2301 monoblocks for about two years now, and while the stock tubes have a lot of life on them still, I'm inclined to swap them out and keep the stock tubes as spares. The threads here on AA are an absolute gold mine of knowledge and links to other great sources of information. Other than a Triode kit amplifier 80BJr, Boss-girl and I built when 80BJr was 12 or so, I've had no other prior experience with tubes, but fell in love with the sound of these components.

I don't intend to roll tubes often, but may do it some with my son's MC275, which is in my care for what may be a few years (:banana:), and is driving a pair of KEF LS50s for the time being.

Looks like the Gold Lions are a smart bet for the KT88s, 12AT7s and 12AX7s (gold pin variants for the preamp tubes), and I intend to get a full matched set and a spare of each, maybe skipping two 12AX7s in the C2500 since I don't use the MM phono stage. I'm also considering Siemens NOS ECC801S/12AT7s and Mullard NOS 12AT7s to roll between the MC275 and C2301. The way my C2500 and MC2301s are racked doesn't make it super-convenient to open and swap tubes, so I'm really looking to settle on something for the life of whatever I buy, but open to playing with the 12AT7s in the MC2301s becuse NOS tubes here are relatively affordable and there are only four of them. The fact we took back my son's MC275 recently is also driving my openness to trying different brands of 12AT7s since we can move them between the two amps.

While my own ears will be the ultimate deciding factor of what I settle on as my default set, are there any other tubes you think may be worthwhile considering if you had this setup? What would have a larger impact on the sound - the line stage 12AX7s in the preamp or 12AT7s in the MC2301s?

I welcome any thoughts based on your experience, including thoughts about rolling 12AX7s vs. 12AT7s in the MC275.

Boy, this turned into a long post - thanks to those of you who made it this far!:D

Paul.......I have rolled many tubes through various preamplifiers and power amplifiers over the years. The experience has been entertaining and educational, but it ultimately comes down to your personal opinion how different tubes impact the sound of your system. I have had very few tubes that I would describe as sounding poor, both power tubes and preamp tubes. For the most part nearly everything I tried produced an enjoyable presentation, although certain tubes delivered additional sonic nuances that pleased me more than others. Again, this comes down to personal taste.

In power tube amplifiers I have used several different manufacturer's tubes, Electro Harmonix, Penta, and Gold Lion. To my ears the Gold Lion KT88's deliver the full audio spectrum in a manner that is musical, robust, and does not overemphasize any portion of the audio frequency range. I have been completely satisfied with Gold Lion KT88's power tubes for many years. Driver tubes in MC2301 power amplifiers have seen me use Siemens ECC801S, Telefunken ECC801S, and GEC A2900 (original Genalex 12AT7 made in Great Britain), as well as Gold Lion 12AT7 Gold Pin tubes. I settled on the Siemens ECC801S as delivering the best clarity and sonic integrity. The Siemens tubes have been in the MC2301 amps now for almost four years. Very pleased with their sound.

In my MC275 power amplifiers, as well as my C2200, C2300, and C1000C/T preamps, I used a number of 12AX7 tubes, Philips, Mullard, Telefunken, Tung-Sol, and Gold Lion. In the MC275 amplifiers the sound was not dramatically different with the exception of the NOS Mullard CV4004 (12AX7) tubes. In the power amps and the preamps the Mullards always displayed a tendency to be a bit bright for my ears. In the different preamplifiers the Tung-Sol 12AX7's and the Gold Lion ECC83 (12AX7) tubes sounded very close to one another. I kept the Tung-Sol's in the C1000C/T longer than the Gold Lions, although The Gold Lion tubes are what is in my C2300 now, that is except for the C2300 phono stage where I use Telefunken ECC83 (12AX7) tubes. They deliver excellent signal to noise ratio in the C2300 moving coil phono stage.

You can be conservative with tube rolling or go hog wild. There are plenty of tubes to try but the rabbit hole is deep if you jump in with both feet. Beware of purchasing NOS tubes from anyone other than totally reliable tube vendors. New old stock tubes are rare these days, and expensive if they are the real deal.

Dan,
Great insights here that build on many of your posts on AA over the years, as well as insights from Tom (W9TR) and others.

The Telefunken ECC83 is an expensive tube, and I was wondering if that price (and that of other 12AX7 variants) was driven more by rarity or demand for better performing tubes. While they are rare, your strong impression of it indicates the high quality. Of course the price/value equation is different for each of us, depending on our ears, wallets and plenty of other factors.

Your point about enjoying most of the tubes you've rolled puts rolling into perspective - not to try to chase a "best" tube but appreciate the differences and find what works best for me and my better half, as I expect her to probably get into it a bit, just as she's been a great partner on the audio and musical journey over the years.

Paul.......You are fortunate your better half appreciates the things you appreciate, especially music and high-end audio. Sharing this interest is a wonderful thing.

My suggestion with tube rolling is to begin with the Gold Lion and Siemens ECC801S (12AT7) tubes in your MC2301 amplifiers. Spend a few days to a week with each set to become genuinely familiar with the sound, then swap the second set in and do the same. You will be able to zero in on the strength of both tube manufacturers. As for power tubes, Gold Lion KT88's have served me extremely well and have provided excellent longevity. I have over six years on my original set of 16 Gold Lion KT88 tubes in my two MC2301's and they are still testing good and sounding excellent. I have 16 brand new Gold Lion KT88's in my tube locker but don't expect I will need them for another five to six years, maybe longer. In my opinion, you can't go wrong with the Gold Lion KT88's.

By the way, TubeMonger.com sells Siemens ECC801S tubes at a reasonable price. I have purchased tubes from them for many years. Good service and fast shipping. Only once did I receive a 12AX7 from them that wasn't matched properly to the remaining ones I purchased. They solved my issue immediately without a problem. You may want to check out their website.

Replacement tubes for Mc C2500 & MC2301 (and a spare MC275)
 

Paul - I agree with Dan’s advice to start with the 12AT7’s in the MC 2301. They make the most difference in the sound.

The Siemens ECC 801 is a good choice as are the Gold Lions. I slightly prefer the Siemens tubes but to me there is not a huge difference between them. The McIntosh OEM tubes are not on the same level as the Siemens or Gold Lions.

I am still running stock McIntosh KT-88’s in one pair of my MC 2301’s. I’ll change them out to Gold Lion KT-88’s when they finally wear out.

I do have a set of 8 SED Winged ‘C’ KT-88’s that I prefer over the Gold Lions, but I need 24 to re-tube, and they are out of production, so they are headed to my MC 275V when the current KT-88’s wear out.

I haven’t rolled a lot of tubes into my MC 275V. I’m using Gold Lions all around right now. I have run original British Mullard CV 4004 and CV4024 in the 275V and think they sounded very nice. When I wore them out I put in Gold Lions. I didn’t do an A/B compare.

Here’s the catch - by the time I pull the amps out, get the covers off, swap the tubes, power up for 20 minutes, listen, cool down, swap tubes, power up for 20 minutes, listen, cool down, rinse, repeat....I’ll be damned if I can really tell a big difference with my imperfect audio memory and overall lack of patience for this kind of stuff. Ultimately I just want to listen.

Telefunken and Siemens 12AX7’s and 12AT7’s are in demand because in some amplifier circuits they make a huge difference in the sound. My experience with these tubes in McIntosh gear is that for whatever reason they don’t make as big a difference as in other brands. But they do make a difference.

I swapped out the original tubes in my C 1100 with Gold Lions and could hear no difference at all. Nada. So back in with the OEM tubes.

My C2300 is a different beast - it sounds much better with the Gold Lion tubes so that’s what has stayed in place.

This summer when I replace the aging MM cartridge in my Rega with a new MC cart I’ll also be looking for a new set of MC phono tubes for my C 2300.

Tom,
"Here’s the catch - by the time I pull the amps out, get the covers off, swap the tubes, power up for 20 minutes, listen, cool down, swap tubes, power up for 20 minutes, listen, cool down, rinse, repeat....I’ll be damned if I can really tell a big difference with my imperfect audio memory and overall lack of patience for this kind of stuff. Ultimately I just want to listen."

That is a good encapsulation of why I've not done this even though I've had the C2500/MC2301s for about two years, in addition to just enjoying the gear with the stock tubes. For instance, my MC2301s are in a low Salamander rack of their own at floor level between the front speakers, but there's a shelf above them that supports my Vox. It probably will be more convenient to take the Vox off that shelf and take the shelf off, then put it back together instead of dragging those monsters out!

Your insights as to what tubes have had more/less impact on the sound is very helpful and will put some things in perspective, especially with the Telefunken and Siemens 12AX7s and your experience with McIntosh. I don't consider my hearing as especially sensitive, and I'm not as articulate in describing what I hear as many on this forum are. Combine that with the range of prices for tubes (10x or more for some brands in production vs. say, Telefunken NOS for 12AX7s), getting your impressions is very helpful as I find a path with my ears, and those of Boss-girl.

Ordered some tubes last week from 3 different vendors. First order arrived yesterday:

- Tungsram ECC83/12AX7s
- Tung-sol (Westinghouse-branded) 12AT7s
- Siemens ECC801/12AT7s

https://www.audioaficionado.org/pict...pictureid=4985

Between these and others coming I should have a 'library' that we can use for a good long while and roll a bit when the mood hits. My order of 21(!) Gold Lion KT88s is on back order, so I may hold off on some changes for a bit.

I also am getting an Orange VT1000 tube tester. I considered some more expensive options, but for my needs at the moment, knowing if a tube is good/bad/weak should suffice.

This is a bit amusing to think that the Siemens tubes were made when I was a freshman in college, and bit more than a year before I took a semester off and sold stereos, where I was the first to sell a CD player, part of the "perfect digital future". Part of that amusement comes from the fact that I'm about to finally get on the Roon/Qobuz bandwagon, where we're getting closer to that ideal.

You’ve got a very nice selection of tubes to play with. Enjoy the ride and don’t get to obsessive with it. :)

We put the Tungsram 12AX7s in the line stage and MC stage of the C2500, and got a bit more detail right away. The stock tubes tested weak after use, so I can't pass judgement on those. Boss-girl, being a Mechanical Engineer, couldn't help but getting into tube rolling. Haven't lugged the MC2301s out yet.

https://www.audioaficionado.org/pict...pictureid=4984

Hi Dan... I just ordered 4 Sienmens ECC801S tubes from tubemonger based on this. Curious to hear the difference between these and the Gold Lions I'm currently running. Thanks!