12B4 eqivalent : sonics-wise ?

[bordins]

Hi,

Generally, my 12B4 preamp sounds so wonderful, particularly crystal-clear high ends and tubey metalic/wind. But the 12B4 seems to offer less "seductive" mid-range, on certain frequecy bands.

I'm looking for a tube that can offer similar sonics but with "better" mid-range.

Any suggestion ? I don't limit only DIY equipment but the commercial tube preamps I've auditioned can't match the 12B4 in that regard.

Thank you.

[Original Burnedfingers]

It would seem that you have found your true love with the 12B4 and I wonder if anything would sound as good to you.

If your game you might try a 5687 or check out the Aikido threads.

The Aikido will smoke any 12B4 I have auditioned so far.

[Brian Beck]

Bordins,

I don’t what your 12B4 schematic looks like, but a lot of the sound character will be due to coupling caps, cathode bypass caps, plate loads and power supply behavior. (This is also true of the Aikido or of any preamp). You can play with these variables to tweak the sound. Sometimes we’re tempted to ascribe the sound of a device to its tube type only, and while that certainly matters a great deal, so do these other things.

Having said that, I can second the suggestion to also try the 5687 (a whole new circuit though).

[bordins]

Hi burnedfingers & Brian,

My 12B4 preamp has premium capacitors and hybrid diode-tube rectifier. The "right" combination rectifier still makes perfect stunning drums while maintains lovely resonant guitar strings.

I find similar sonics on other 12B4 preamps using cheaper capacitors that make me believe this is 12B4's signature.

I wonder which Aikido threads to start with. There are plenty of them. TubeCad offers the whole amplifier. I need only a line stage. My amp is still SS.

Thanks a lot.

[Salas]

The 12B4 is ultra low rp. Tubes like that, 6H30Π etc. always sound more 'transparent & technically correct'. The lower the impedances the higher the currents, the closer to how ss works minus the solid physics and pentode like curves. The high tension low ma world has a distinctive signature opposed to lower tension high ma world. Its like Conrad Johnson vs Audio Reasearch kind of comparison. For a system to contain the transparency and not verge to sterile, all components, cables & speakers must be low fatigue. To me there is ground in attributing 'coldness' to the 12B4 device when dropped in a non ready system, akin to dropping a Benchmark DAC1 in a non neutral easily challenged hi-fi system. such devices are correct, yet demanding.

[bordins]

Hi salas,

My gear should offer good transparancy: Scanspeak Revelator 18W8531G00 & D2904-7100, Oritek X-2 cable (the most transparant cable I have ever heard !!), Kimber 4VS speaker cables, bi-polar transistor-based 300W SS amp.

At first I thought the 12B4 is very transparant as many have said, but the tubey sounds make me believe it adds something, very nice thing though. The "flaw" are at certain mid-range bands. As I mentioned, I hear it in all systems using 12B4.

[Salas]

Better use 5687 in combination with 300W ss amp. Also Kiwame and Silmic around the tube.

[Eusebius]

To go a step better than the 12b4 I suggest you go into the world of DHTs (Directly Heated Triodes).

You can try any of 01A, 12A, 30, 31, 1G4, 1H4 - all good. To my ears they all sound better than 12b4 and some of them sound considerably better. I have a 12b4 preamp but never use it, and one day I'll change the tubes to DHTs.

You will need a good filament supply and a very solid base to put the tube sockets on to avoid microphonics. You'll find this kind of information on other threads if you do a search, or I can email you a schematic. Andy

[aletheian]

This is most certaily out of my league as far as contributing is concerned, but I am curious... that resistors are you using?

[bordins]

Originally posted by aletheian
I am curious... that resistors are you using?

Aletheian, I checked with my friend who built the preamp for me. The resisters should be Dale (metalic).

I also found some opinions about 12B4 v.s. 5687:

Originally posted by fedegrove
For a preamp that's going to be fed mainly by a CDP I'd rather use a 12B4A.

To my ears and mind it's far better suited and doesn't suffer the rather darkish colourations of a 5687 being pretty transparent.

from http://www.diyaudio.com/forums/showt...335#post518335

Originally posted by burnedfingers
I have built several 6SN7's, 5687, 6922, and 12B4 line stages.

In my opinion the 12B4 vastly out performs the 5687. I was happy with my 5687 until I built Brett's 12B4. After building the 12B4 the 5687 has been scrapped.

http://www.diyaudio.com/forums/showt...631#post518631

Burnedfingers, I found your post saying 12B4 is bertter than 5687. Was it before you knew Aikido with 5687 ?