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Ray,Like most things audio, having the right topology and implementation will set the stage for the sound of it, among other parameters. Then you can start getting into parts selection and tuning to taste with tubes for those cases. One supplier that offers both tube and SS versions of his products such as preamps and CD players is Dan at Modwright. It's one of those rare cases where customers can tell you about the same audio sections powered by either SS or tube supplies. Specifically, I believe the Modwright Sony 999ES Platinum, SWL9.0SE, and LS36.5 preamps have all been offered both ways (check Dan's forum for sure though). There has been a lot written about it you can refer to, so you might want to inquire or take a look over there.Happy hunting!Tom
Ray,It would help in answering your question, if we knew what the rest of your system is and what you find wrong with it.Mike
I will second the Mapletree preamps. My Ultra 4A SE can use either 12SN7, 12SX7 or 6SN7's for variety, although I've only used the stock 12SN7's so far. I hear you can also swap the 6X5 rectifier in the power supply, but havn't done that yet either.
Ray,If you decide to go for tube rectification, that will give you another point of fine tuning the overall sound of your system. Rectifier tubes all sound different, just like driver and output tubes. Some have better bass, some smoother highs, some better midrange. All of this is subjective of course but it does allow you the ability to further tune the sound of your system to better suit your ears.There is nothing wrong with either approach. Both sound just fine. I have both types of rectification in my systems. If it were me using solid state downstream, I'd probably choose the tube rectification, just for that last little bit of fine tuning. Now I'll likely get push back on this one but I (personally) wouldn't go for a 6922 in the preamp. Not because of the sound but more so because of the limited selection (and price) of the 6922 tubes. The 12 series tubes have a far greater selection at far wider price points to pick from. You can buy a cheap RCA or Sylvania for five bucks each all the way up to a 50 or 75 dollar Telefunken smooth plate. Somewhere in between the cheap and the expensive NOS tubes you will be able to find what sounds the best to you and your pocketbook. With the 6922, your choices are far more limited. Sure, you can buy an OK sounding new production tube but the far better sounding NOS tubes get pricey quick. That and there are far fewer 6922 NOS manufacturers to choose from. You 6922 fans, please don't push back too hard. You have to admit that there is a far better (and cheaper) 12 series selection of tubes to pick from.
Regarding SS vs. tube rectification, either can be very good, or very mediocre. With tube rectifiers, everyone is a bit different ... Some people like being able to tune for sound by rolling tubes -- I hate it, and want things to sound good regardless. It bugs me that Sylvania 5U4GBs and RCA 5U4Gs sound best in my power amps, when I have a dozen Tungsols and GEs lying unused. I have another tube amp with solid state rectification, and it always sounds good. No characteristic "sound", as the power supply was properly designed around one set of SS diodes that will last forever. But, as Tom said, the design as a whole matters. If it is done well, the rectification shouldn't be an issue, just a design choice.Regarding Scott's comment on 6922s, I have personally gotten some real bargains, allowing me to accumulate about 50 of 'em, 30 new-in-box, for not too much $$$. My biggest complaint with 6DJ8s and 6922s is noise -- knock one over and one channel is almost guaranteed to go. I find that the more expensive ones are even more likely to go noisy when knocked around. You can drop a 12AU7 from a couple feet, and it usually doesn't mind. But for conventional circuits, I'd generally rather listen to a 6922 over a 12AU7. The 12AU7's granduncle, the 6SN7, is technically a much better tube. It is easier to get very low distortion using a 6SN7, 6922, or 6N30P/6H30Pi (another great tube, IMHO!) than a 12AU7. But I don't want to get into any fights here... Edit--as a further caveat, the circuit itself will make a bigger difference than the tubes themselves. Some of the least-linear 12A*7s, the 12AT7s, sound fantastic if you wrap a bunch of feedback around them (like in the Harman Kardon Citation I). The 12AU7 in a grounded-grid sounds nothing like a normal 12AU7 circuit. And, of course, 6DJ8/6922s sound terrible when oscillating, and the 6SN7 can even be made to sound bad if one tries hard enough
A few comments to toss in here just technically.Since a 12AX7 and a 6922 are such very different devices, the circuits in which they are used are also then very different. Since circuit topology itself determines such a large percentage of the final sound, you are never really just comparing the two tube types per se, but rather hearing the whole of the circuit. In line stages especially, a large contribution to the final sound is coupling capacitors. In some circuits more than the contribution of the tube type/vendor/make. Some circuits will be very sensitive to tube rolling within the type, and some will be much less so. Again, topology will play a big role there. That's no argument for or against any particular tube - only an argument that such comparison isn't very easy.
Quote from: JuicyMusic on 27 Jan 2008, 09:45 pmA few comments to toss in here just technically.Since a 12AX7 and a 6922 are such very different devices, the circuits in which they are used are also then very different. Since circuit topology itself determines such a large percentage of the final sound, you are never really just comparing the two tube types per se, but rather hearing the whole of the circuit. In line stages especially, a large contribution to the final sound is coupling capacitors. In some circuits more than the contribution of the tube type/vendor/make. Some circuits will be very sensitive to tube rolling within the type, and some will be much less so. Again, topology will play a big role there. That's no argument for or against any particular tube - only an argument that such comparison isn't very easy.Hi Mark,Well, thatg brings up a question.:Is there anyway you could use part of the 6922 or 6H30 as a regulator and the other half as the amplifier. I realize you would have two tubes one per channel as opposed to the one tube for both channels.Just curious. Ray.
Quote from: Ray Bronk on 28 Jan 2008, 01:46 amQuote from: JuicyMusic on 27 Jan 2008, 09:45 pmA few comments to toss in here just technically.Since a 12AX7 and a 6922 are such very different devices, the circuits in which they are used are also then very different. Since circuit topology itself determines such a large percentage of the final sound, you are never really just comparing the two tube types per se, but rather hearing the whole of the circuit. In line stages especially, a large contribution to the final sound is coupling capacitors. In some circuits more than the contribution of the tube type/vendor/make. Some circuits will be very sensitive to tube rolling within the type, and some will be much less so. Again, topology will play a big role there. That's no argument for or against any particular tube - only an argument that such comparison isn't very easy.Hi Mark,Well, thatg brings up a question.:Is there anyway you could use part of the 6922 or 6H30 as a regulator and the other half as the amplifier. I realize you would have two tubes one per channel as opposed to the one tube for both channels.Just curious. Ray.You could certainly use 1/2 for a current source and half as an amplifier.
