Tube Rookie, Purchase extra tubes?

Just purchased a McIntosh 2152 tube amp. Do I need to purchase extra tubes for just in case? If I do, am I forced to buy an entire set or just a couple of each size? Uses 8-kt88’s and 4 each 12ax7a and 12at7. Like I said I’m a tube newbie.

 

I would not worry about KT88 supplies. But the best 12AX7s are becoming scare and future availability is questionable. Pay the price and buy Mullard 12AX7 long plates. Good high performance RCA 12AT7 are not expensive, so squirrel away the RCA 12AT7.

 

I'd just listen and enjoy for a while, like a month or 2. Get used to the sound, see what you enjoy the most about it, and maybe ... what you might wish to improve if anything. If there's nothing that stands out that seems a little lacking (and hopefully there's NOTHING that seems more than a very little tidbit of lacking) ... don't worry about it !!!

After a month or 3 or 12 ... during that time do more research on what the small tubes 'do' in the circuit(s). Like allied333 said, the large tubes (power tubes) are readily available but also are more $$$. They should last more than a year or 3 even if playing a lot. Same for the small tubes, but being less $$$ may be fun to experiment with after a while. Likely all of them will 'last' and perform well for several years before even 'thinking' about needing replaced. But of course 'stuff happens'.

Errrr ... becoming rare/scarce? maybe for (very few?) CERTAIN 'new old stock' (NOS) 12AX7s like 333 is talking about ... but all these tubes are still being produced, so it's not like there will be a shortage of new ones to use. NOS Mullard 12AX7 long plates? Maybe they're the cat's meow in some amps/preamps, but IIUC in general Mullards are generally a bit softer/richer sounding. If your amp/system is already nice sonically to you in this regard, why spend $$$ on something that may make it lean further in that direction? Tubes, depending on function in the circuit, can certainly flavor the sound, reinforce certain aspects of the sound, etc..

I swapped the original 12AT7 driver tubes in my Bottlehead 300B tube amps to (like these) Siemens & Halske NOS triple-mica 12AT7s to get a bit more clarity and 'crispness' to the sound. Wonderful and worth every penny I paid.

Some tubes/positions in a circuit don't have a lot of effect on the sound ... so spending $$$ won't yield sonic improvements or changes. Others can and do. Research your amp! Find out what tubes do what ... this is a new amp but may be based on a classic type circuit by McIntosh. There will be 'literature' on how the tubes work and affect the sonics. Good luck!

 

Mullard ECC83 / 12AX7 don't know if these are 'long plates' (I'm not an expert) but can't see spending $200 each unless you KNOW these will flavor the sound they way you want! Then, yes, might be worth every penny!

I got some of these Genalex - Gold Lion B759 / ECC83 / 12AX7 Preamp Vacuum Tube for my McIntosh C220 preamp (when I owned it). Excellent improvement over the 'JJ'? tubes that came with it (mine was one of the first C220s ever produced). I think Gold Lions MAY be the tubes that come with the new McIntoshes these days? They'll be branded as McIntosh most likely though.

 

Get used to the sound of the amp for a while, and after a couple of months buy some extra 12ax7s and 12AT7s. But try-out some different tubes than what you are currently running. Tube rolling is a lot of fun, and it can be really help you to tune an amp to sound exactly how you want for it to sound.

There is no need to go crazy on the NOS tubes at first. Fortunately some great NOS 12AT7s are still affordably priced. But NOS 12AX7s are quite spendy. So I'd recommend playing around with current production 12AX7s first to see if you can find any current production tubes which really make your amp sing before spending the big bucks on NOS 12ax7s.

 

Personally, I would try rolling preamp tubes (small ones) after a month or two. KT88 power tubes should be the last to roll however it would be wise to have a spare set of 2 power tubes on hand at all times. You never know when a tube will die but in your case if purchased brand new that should take a while.

 

Here is what I know about Mullard 12AX7 long plate. These tubes produce the lowest distortion I ever heard in many different amps. If you have a quality system that will easily distinguish different distortion levels, the Mullard 12AX7 long plate cannot be beat IMO.

BTW- most Mullard 12AX7 long plate on ebay are used up. Many do not even test at 1000gm whereas 1400gm is good and 1600gm is new. Brent Jessie has new Mullard 12AX7 long plate for sale.

 

Interesting discussion. I recently replaced tubes in my Jolida cd player with Sylvania NOS from the 50s. After a few hours of breakin, I really could hear an improvement in the sound. My Jolida hybrid integrated amp came with Brimar tubes in the preamp. I've been told these are excellent tubes but wondered if it's worth rolling some new ones?

 

I want to thank everyone who responded. I appreciate the help.

 

Makes sense, I assume a pair since the amp is push-pull? So best to replace in pairs (especially if different brand than original)? Replacements may/should be available thru McIntosh too, altho will be pricey and maybe not the 'ultimate' in sonics as deemed by aftermarket enthusiasts. McIntosh goes for technical performance, longevity/reliability, and then sonics ... at least that's how it seems to me and many others. Not a bad thing when designing products that are intended to last 30 or 40 years.

Certainly seems like a good tube to have/use, just that the 'flavor' may tweak things a little in a direction that isn't optimal for a given amp/system ... of course it may be the best tube ever as well.

YES! If you have extra $$$ to spend, and you don't have to spend a fortune, it's really fun and good to roll tubes and see what you think. Try doing some research though as I said above ... someone may have done this already in your amp and can suggest what tubes/positions give the best results, or at least in what direction the sonics may lean. Maybe some give really 'neutral' improvements in musicality or resolution, which is great. Some may do some of that but also result in the sound becoming more smooth ... which may be just what is needed. Some (like my triple mica Siemens 12AT7s) may give a bit more 'zing' to the sound, which was needed in my system. Hard for me to say, but one of the most enjoyable things about tube gear is improving and/or flavoring the sonics, spending $60 or so on a new or NOS or 'used, tested good' pair of tubes. Not that a $20 pair can't do similar things ... or a $200 pair. But $60 to me is a good 'experimental' price that won't upset me if things don't change or whatever, and I'd have a spare set there if something does happen with a tube.

You can also swap tubes as you like, maybe want warm smooth sound in the winter and brisk high res sound in the spring!

 

IMO, it's always a good idea to have one extra power tube on hand because that is what's likely to fail. Who wants to wait a week for a replacement to be shipped when it does?

 

It’s simple and was already mentioned above
Buy a set of NOS tubes ... no, buy two sets, because they are getting increasingly rare
You won’t lose money. You will gain ...
Best tubes are Telefunken (you will not find so many old Mullards), but there will be quite a hole in your pocket.
If that’s too expensive buy Siemens.
If that’s still too ex, buy RFT (from old eastern Germany), bit a secret tip
American tubes were never that good (sorry to say), they sound veiled

“Will it improve the sound (shiver)” ... yessss! More than you can imagine. Much more.
And forget about KT 88 NOS, the driver tubes make the biggest difference

 

Technically, you could just have 1 spare power tube on hand and be fine. I always order a pair of tubes, so if one goes I still have another spare.

 

ONE spare power tube ... or two ... I would think they should be the same brand as the originals? IIUC McIntosh brands their tubes, but occasionally changes suppliers. So ... McIntosh brand from current supply? as this is a brand new amp. OR if someone knows these are actually (say) Electro-Harmonix or whatever, one could get one or 2 of these and be assured things would 'be the same' as with the OEM tubes.

 

Mac tube amps have historically been very easy on their tubes. I would expect them to last years.

BillWojo

 

Don’t you need to replace all the power tubes in each channel as a matched set?

 

I’m unfamiliar with McIntosh gear but my tube amp allows for individual power tube biasing so I don’t need buy matched sets.

I do always get the same power tubes to maintain consistency. There was a time though where I had to use a different brand power tube temporarily since I was waiting for the spare tubes and if memory serves I could hardly tell the difference in sound with 1 different power tube.

 

In an amp with auto-biasing output tubes can be individually replaced, the amp will set the correct bias. In such a fine amp as this I would expect it to have auto-bias or individual tube bias. I don't see this info anywhere online. My auto-bias amp included one extra output tube.

From the manual:
Tube Compliment 4 - 12AX7A Input and Phase Inverter.
4 - 12AT7 Voltage Amplifier and Driver.

The gain stage (Voltage Amplifier) and drivers will have the most effect on sound signature. These would be the first tubes to roll after you spend some time with your amp. You're lucky since NOS 12AT7's are very affordable.

 

Phase invertors have little effect on the sound. Sovtek 12AX7LPS work as good as any tube.

 

Thanks for clarifying! I am way more familiar with tube guitar amps than I am hi-fi amps...

 

If you spent thousands of dollars for the McIntosh amp you can surely have a few backup tubes just in case. I would probably purchase two tubes each for spares even though you amp is new. You never can tell when a tube will go bad.

 

Could not possibly disagree more. Phase invertors have had a very noticeable impact in all of my amps.

And if you like a somewhat dull sounding tube, then the LPS is good choice.

 

In amps where one tube functions as both driver and phase inverter, there is definitely an influence on sound.

 

It is actually extremely common for invertors to do double-duty, whether the inverter be a long tailed pair or a split load invertor.

 

Drivers and phase inverters are very important for the sound. IMHO it's input tubes>drivers & Phase inverters >power tubes (that if we talk about different brands of the same model, because if we replace for example EL34's with KT150's it's another story).

I have a PrimaLuna integrated, and there's a common statement that says with these amps, you only need to roll power tubes and input tubes because the drivers don't affect the sound. It's written somewhere and people repeat it like a parrot without even bothering in trying.

I don't even know how it works, all I know is that I have four 12AU7's that are drivers and phase inverters but I don't know if one tube does one thing, the other does the other thing or half of each tube is driver and phase inverter, I'm not handy with circuits and stuff, but I know all small signal tubes are very important for the sound.