2. amps-preamps
  3. 147225-115924

Tube Rolling for Pre-amps?

I have an Audio Research LS-16 that feeds a Madrigal Proceed HPA2 solid state amp. 

I did not choose this equipment; it was given to me. From what I can tell the original owner spent a good bit of time matching up these two components with the speakers, Aerial Acoustics 7Bs.

The tubes in the AR are original. Probably 10-15 years old? But with an extended period of not being used.

The system sounds good to me. I don't need to change anything.

However, I've been told that the tubes are old and may need to be replaced soon. I've also read a little bit about tube rolling but most of the articles I've seen talk mostly about tube rolling with amps and not pre-amps.

So I have some questions:

1) If the original owner wanted a system that sounded like a 'tube' system, why not have a tube amp and pre-amp? Does it make sense to have a tube pre but SS amp?

2) Other than outright failure, how will I know if my tubes _need_ to be replaced?

3) With a SS amp, will changing tubes in the pre-amp have a noticeable impact on SQ? In other words, is tube rolling for a pre-amp played through a SS amp a thing?

4) For someone like myself who is happy with the system and who is also easily frustrated by A/B testing is tube rolling the pre-amp even worthwhile? I can almost always hear a change when comparing various components but only rarely am able to say A is better or worse than B.

( I probably can't even articulate effectively what I look for in terms of SQ except that I like the bass to be tight, precise, well defined and not boomy. I do not like the music to be overly bright or tinny. I like depth and lushness but not overly warm. Not sure if these are things you alter with tubes.)

Thanks for any advice.


n80
n80 OP
2,116 posts
 
@lowrider57  : " n80, you have no baseline or reference to judge the SQ of your preamp."

That's what I'm saying. It is a blessing and a curse! The blessing is that I think it sounds great. The curse is that it might not. ;-)

I don't remember where those prices came from. Just a Google search. I don't know anything about types. This is what comes in the pre-amp:   6922/E88CC dual triode. It takes 4.
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whart's avatar
whart
3,022 posts
 
@lowrider57 -Brent Jesse is cool.
@n80- call him, don’t try to decipher that website. It will drive you absolutely bonkers. I didn’t deal with him for years because trying to decode his website was like reading a bad spreadsheet. He’s a really good guy, and knows tubes, isn’t overpriced and is very fair in my experience. He’s also not a BS seller, which in vintage tubes is very common. There are also some mistakes that can be made out of pure ignorance. I’ve made them. I bought some NOS Mullards printed on the glass as "Made in Great Britain" or some such. Turns out, back in the day, tube manufacturers shifted production even to unaffiliated companies given demand and supply. My British tubes were actually made by Amperex in the US. The seller (not Brent) didn’t know that, and neither did I.
A reliable supplier of tubes is pretty essential, unless you really go full geek. I’m sure there are some posters here who qualify (I don’t mean ’geek’ in a bad way, just that you have to dig deep). It’s another part of the history of this hobby that we live with today and is at times fascinating, frustrating and often maddening.
rodman99999
6,109 posts
 
Yes- Only changing two tubes(either V1 & 2, or V3 & 4) will generally provide you with a good slice of what can be expected, if all are swapped. I’ve avoided counterfeits and junk, by only purchasing from reputable tube mongers. ie(for nine pin miniatures): Brent Jesse, Tube Depot, or this guy from whom I’ve purchased the most: https://www.ebay.com/sch/audiotubes_de/m.html?_nkw=&_armrs=1&_ipg=&_from= Upscale only refuses to sell their NOS tubes, for use in pro audio equipment. They have lots of NOS 6DJ8 types, for home audio. I found everything that Siemens made, after the early/mid 60s, grey shield CCa, a bit too zingy/bright for my tastes, but- that could just be the rest of my system, ears or preference. I only said what I did, about live music, because after extended listening in good, live venues- one sometimes gets spoiled(perhaps, educated) and the average home audio system MAY then sound, "broken".
n80 OP
2,116 posts
 
@elizabeth : It takes an effort to keep the 'inner audiophile' tame. Even some of the stuff I consider to be wacko beckons at times. But I also have an inner Scotsman that delights in high bang-for-buck ratios which becomes a hobby in itself and helps keep my over-the-top hobby tendencies at bay. I love a bargain that fits a need!

@lowrider57  : I don't think I'll end up being a tube geek. Having a back up set makes sense and I'll probably do that if I can do it affordably. But then that's the first step isn't it? Get the back up tubes. Can't resist trying them out. Like the way they sound. Wonder about a different set.............

@rodman99999 : Currently my live music consists of the symphony 3 - 4 times a year, opera maybe once a year. But that's not what I tend to listen to on my system. I go to loud rock shows a few times a year. SQ at those shows is never great. Fun shows though.
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