Best preamp for testing tubes

[IvanMike]

well i've swapped tubes in a bunch of preamps. (btw, the demeter 201 and 201s use two tubes, and changing one makes a difference, the order makes a difference (if you're using two tubes), but to get the real feel for a tube in those units you need to have two of everything and change two at once.

overall, i've found that every preamp reacts a bit differently to tube swaps. some preamps make tubes sound different. It's going to be hard to make across the board generalizations about tubes as the preamps can affect them to the point where you'll get different opinions on a swap depending upon what preamp you use.

Not what you wanted to hear, but IME, it's the case. IME, i've found the preamp makes a lot more difference than the tube. An SWR compared to a demeter still sounds like an SWR compared to a demeter regardless of what tube is in each. I played with a bunch of tubes in my 201 (telefunken, groove chinese, RCA, mullard, EH, sovtek, etc.....), and there were some changes, but overall it always sounded like a 201.

 

[tombowlus]

well i've swapped tubes in a bunch of preamps. (btw, the demeter 201 and 201s use two tubes, and changing one makes a difference, the order makes a difference (if you're using two tubes), but to get the real feel for a tube in those units you need to have two of everything and change two at once.

overall, i've found that every preamp reacts a bit differently to tube swaps. some preamps make tubes sound different. It's going to be hard to make across the board generalizations about tubes as the preamps can affect them to the point where you'll get different opinions on a swap depending upon what preamp you use.

Not what you wanted to hear, but IME, it's the case. IME, i've found the preamp makes a lot more difference than the tube. An SWR compared to a demeter still sounds like an SWR compared to a demeter regardless of what tube is in each. I played with a bunch of tubes in my 201 (telefunken, groove chinese, RCA, mullard, EH, sovtek, etc.....), and there were some changes, but overall it always sounded like a 201.

Actually, that is the kind of feedback that is very helpful, and quite true. I do have at least two of many of the various tubes I have to play with, but maybe the F-1X is the way to go - at least for initial thoughts. Or perhaps the Chandler.

 

[John D Harris]

well i've swapped tubes in a bunch of preamps. (btw, the demeter 201 and 201s use two tubes, and changing one makes a difference, the order makes a difference (if you're using two tubes), but to get the real feel for a tube in those units you need to have two of everything and change two at once.

overall, i've found that every preamp reacts a bit differently to tube swaps. some preamps make tubes sound different. It's going to be hard to make across the board generalizations about tubes as the preamps can affect them to the point where you'll get different opinions on a swap depending upon what preamp you use.

Not what you wanted to hear, but IME, it's the case. IME, i've found the preamp makes a lot more difference than the tube. An SWR compared to a demeter still sounds like an SWR compared to a demeter regardless of what tube is in each. I played with a bunch of tubes in my 201 (telefunken, groove chinese, RCA, mullard, EH, sovtek, etc.....), and there were some changes, but overall it always sounded like a 201.

Mike,
In my experience, the tube on the left side (if you're facing the front of the 201S) has by far the most influence on the tone of the Dem.
The tube on the right at most has an extremely subtle influence on the sound.
The left tube is used for two circuits: gain & tone.
The right tube is used for two circuits: the FX loop & output.

Does your experience differ from mine?

Also, which tubes do you prefer in the Dem?

[I'm currently using a Jan Philips 12AX7WA & a Sylvania 7025 (from what I understand, the same tube design).]

 

[IvanMike]

Mike,
In my experience, the tube on the left side (if you're facing the front of the 201S) has by far the most influence on the tone of the Dem.
The tube on the right at most has an extremely subtle influence on the sound.
The left tube is used for two circuits: gain & tone.
The right tube is used for two circuits: the FX loop & output.

Does your experience differ from mine?

Also, which tubes do you prefer in the Dem?

[I'm currently using a Jan Philips 12AX7WA & a Sylvania 7025 (from what I understand, the same tube design).]

i agree the left has the most impact

i have the older 201 (although not the really old one, mine has rocker switches for the bass and presence eq centers). testing that aganst a new 201s i found the 201 to have more low end and the 201s to have more high end extension. in the 201 1.5u i actually prefer chinese tubes for the high end. i know a lot of cats like telefunkens in the demeter, and for the 201s that may be the ticket, but for me the 201 1.5u already has plenty booty and just does well with the extra hi end kick of the chinese tubes

 

[John D Harris]

i agree the left has the most impact

i have the older 201 (although not the really old one, mine has rocker switches for the bass and presence eq centers). testing that aganst a new 201s i found the 201 to have more low end and the 201s to have more high end extension. in the 201 1.5u i actually prefer chinese tubes for the high end. i know a lot of cats like telefunkens in the demeter, and for the 201s that may be the ticket, but for me the 201 1.5u already has plenty booty and just does well with the extra hi end kick of the chinese tubes

I bet Matsush!ta tubes would work well in it, I ran one for awhile in my 201S on the left side.
Seems to have a rather lean tone (taut in the bass & without a lot of harmonics), but very fast and articulate in the mids and highs (but, like I said, not nearly as harmonically rich as the Russian tubes).
In the 201S, I preferred the Jan Philips & Sylvania -- haven't tried any Telefunkens yet.

Side note to TomB:
I hate to bring up the subject of "gain matching" after one of the recently deceased threads in which this came up (again & again & again), but as the Telefunkens are usually higher gain than most of the other 12AX7 tubes, that might be something to take into consideration when comparing them against others (maybe part of why they seem to be popular).

 

[tombowlus]

Side note to TomB:
I hate to bring up the subject of "gain matching" after one of the recently deceased threads in which this came up (again & again & again), but as the Telefunkens are usually higher gain than most of the other 12AX7 tubes, that might be something to take into consideration when comparing them against others (maybe part of why they seem to be popular).

Interesting. I was not aware of that issue. It would probably be most prevalent when used in an overdrive valve stage.

But of course, I do plan on acquiring all the necessary equipment to accurately calibrate my gain stages anyways...

 

[boogiebass]

Tom, You really need a Kern, dude!

 

[tombowlus]

Tom, You really need a Kern, dude!

Not helping! Not helping!























Okay, who's selling a Kern or a Read?

 

[Mark Reccord]

I'd use the Demeter, buit that's just me...

Trying to mod a True Voice for 12__7 tubes is a waste of time. The 6SN7 is a very very different animal than the 12__7 variants.

 

[tombowlus]

I'd use the Demeter, buit that's just me...

Thanks for the advice. Would you leave a fairly neutral sounding tube in V2, and just swap out V1, or would you try to test tubes in pairs?

Trying to mod a True Voice for 12__7 tubes is a waste of time. The 6SN7 is a very very different animal than the 12__7 variants.

That was my suspicion.

 

[Mark Reccord]

Thanks for the advice. Would you leave a fairly neutral sounding tube in V2, and just swap out V1, or would you try to test tubes in pairs?

I'd start by putting a reference tube in V2 and swapping V1, then maybe doing the opposite. Testing in pairs adds a degree of complexity and an extra variable, so I'd avoid it if possible.

Interesting about the True Voice...... I've been thinking about designing a 6SN7-based bass preamp for about a year and a half, but I've been too busy with school to follow up on it.

 

[tombowlus]

Interesting about the True Voice...... I've been thinking about designing a 6SN7-based bass preamp for about a year and a half, but I've been too busy with school to follow up on it.

If you do get around to it, and you plan on making any available to the bass playing public, be sure to let us know!

Tom.

 

[ganttbos]

I've done a little tube switching:

My 659 sounds the most "tubey" to me of the three pres I've experimented with - the other two are the Read and the Dem 201 (blackface 1.5 space). With NOS Sylvanias the Ag sounds almost too mushy but then in a mix it's very comfortable to play, if that makes sense. There's no struggle - simple bass lines sound like they're "enough" whereas with my 201s the clarity makes the same simple line sound almost "kindergarten" - I feel the need to embellish. I ended up selling my Dem for that reason. I tried to smooth out the Dem with various combinations of NOS GE's and RCA's I got from Chuck Moses, but although there were differences, it retained that clear defined Demeter sound that, for me, is too clean. For jazz guys, or for better players than myself in general perhaps, the Dem would be a dream come true. I was originally conditioned by an SVT using flats so I'm an early 70's rock tone guy. A Telefunken in the 659 was too tubey to my ears (too easily overdriven) and a JJ Tesla made the Ag sound most aggressive. With the Read the Telefunken (in the 12ax7 slot) is very smooth - the best compromise I've found so far - and my present gig rig of choice. The difference between various 12ax7's in the Read is in-your-face obvious to my ears.

 

[tombowlus]

The difference between various 12ax7's in the Read is in-your-face obvious to my ears.

I'm beginning to suspect that resistance is futile!

 

[tombowlus]

Can someone point me to a photo of the back panel on the Read Purity?

Thanks, Tom.

 

[Fuzzbass]

The Read Purity has a 12ax7 and a 12au7 both sticking out of the back of the preamp casing. You can change tubes without even unracking the pre. (Sorry Tom, but you know you want one anyway )

Deepest apologies, Tom, but I have to mention a special feature of the Read Purity that would be highly useful for your tube testing: the EQ bypass switch. Flip into bypass mode, and no more worries about whether the EQ is truly set flat.

 

[tombowlus]

Deepest apologies, Tom, but I have to mention a special feature of the Read Purity that would be highly useful for your tube testing: the EQ bypass switch. Flip into bypass mode, and no more worries about whether the EQ is truly set flat.

FYI, I did talk to Jack this morning...

 

[tombowlus]

All these Read/Kern suggestions have me spending more time back at one of my favorite sites. You guessed it - www.basstasters.com! [Thanks again Todd! You rule!]

At any rate, I really do hear where the Kern sounds like a slightly beefed up F-1X (I am paraphrasing here from other comments that I have read). But, the F-1X sounds like it has a tad more clarity, which I like. Does this sound accurate? Also, while I like the low end authority of the Kern, it seems a bit soft and pillowy down low. The DB 659 seems to have just as much, if not more, of that low end girth, but with more clarity and overall tightness. The Sad V groove clips really show this.

And while the Read Purity sounds really good, I haven't really found any clips where I prefer it to the DB 680 (currently my favorite tube preamp). I like the ease of changing tubes, but with any luck, that is going to be a one time experiment (or a several night series of events, more likely), and ultimately, it's how it sounds on the gig (and in the studio) that matters. Can any of you folks who've played both the Read and the DB 680 provide me with some more comparative notes? I must say, though, after talkng to Jack Read on the phone today, I would feel really, really good buying a preamp from that man. What a swell guy to talk to!

But as for the Kern, at least going by the basstasters clips, other than the ease of swapping tubes, I don't see where it offers much over the F-1X and/or DB 659. Am I missing something? If so, please set me straight.

At this point, my plan is to focus on the 659, F-1X and 201s (when it comes in - this week, I think) and do a few "trial runs" with tubes that I am already somewhat familiar with. Then, I'll pick one and stick with it for a while, and use one or more of the others for "second opinions."

Thanks to all who have contributed to this thread, even though you have contributed to my GAS (as if I need that!).

Take care, Tom.

 

[r379]

Tom;

I haven't taken my F1-X apart yet to try different tubes so this is just an idea. If your notion is to find one preamp to use as a reference point for testing tubes then maybe the F1-X is the one to use. Why? Because it only has one tube and for that reason you'll see the effect of one tube without wondering if changing/not changing the other tube is screwing up your experiment. Just an idea.

Richard

 

[tombowlus]

Tom;

I haven't taken my F1-X apart yet to try different tubes so this is just an idea. If your notion is to find one preamp to use as a reference point for testing tubes then maybe the F1-X is the one to use. Why? Because it only has one tube and for that reason you'll see the effect of one tube without wondering if changing/not changing the other tube is screwing up your experiment. Just an idea.

Richard

That is certainly one of the compelling reasons for using the Alembic. I have a bunch of NOS tubes, and I have a bunch of tube gear. Rather than go through the lot of them in each valve socket on each amp, I'd like a general idea of what sonic characteristics I might expect from a given tube. Obviously, the interaction between a certain tube and a certain preamp is going to vary quite a bit, and I know that I can't rely on a given tube sounding the same in every preamp. But, I hope to at least have a starting point.

Thanks, Tom.