aerius

I'm currently taking a break from a mini-meet, it got pretty intense and my friend & I are taking a break to go grab some food and catch up on things a bit before returning to the listening. A little teaser, we have a modded Audio Aero Capitole, a custom built 2A3 amp, and a balanced RS-1 recabled with copper litz wire. For shits & giggles, we decided to compare a regular store bought CD (Tori Amos - Boys for Pele) with a CDR copy burned on a Fujifilm CDR. I've heard people saying CDRs sound better but never heard a difference on my system, so since we had a top-notch system at our disposal we decided to test it out. Shockingly, the CDR sounds better, and I was like "what the fuck?!" More to come later...

Here it is in rough schematic form, please excuse the lousy handwriting.

But they use them in the $20,000 (or whatever the hell it costs) Zanden, therefore it must be good! I don't think I've heard a DAC with one of those TDA chips, but I can't say it's a life experience I desperately need either. I have the PCM1700 in my CD player and like what it does, and I've heard the PCM1702 in Biggie's player and really liked that. The ones I do want to hear at some point are the PCM63 and PCM1704.

The funny part is how true that is. I've recently heard of TDA 154X chips going for the same price on ebay as a good NOS tube.

Heh heh heh, it's always hilarious to see immtbiker and the other mods get owned and made to look like retarded tools. On a sidenote, it's pretty true what Mike said a while back, once you get used to SD.net debating, you can ruin almost everyone at most other forums. On another sidenote, are you aware of the headphone fetish site? And finally, welcome to head-case!

I can't say I'm surprised. As they say, one man's garbage is another man's treasure...

That is pure comedy gold! Posting that on Head-fi will probably get you banned on the spot though.

Your mom's a dumb broad.

Hi, my name is aerius, and I'm fucking drunk. I'm posting on head-case while drunk. Boo-yah-kah fuck yeah!!!

Pick up some hot college chicks while you're at it.

Looks good as far as I can tell, I don't see any issues with it. The power supply's going to be a shitload of fun though, and not in a good way. Also, latest update on Art-tard.

Pretty soon I'll be able to find out first hand. I scored a couple used 2A3's at the surplus shop today ($3 each, bitch!) and I'm planning to build something with them this year. Also got a bunch of 6BQ5's, 12W6's, 0C3's, 0D3's and a big box of 6CM3 damper diodes. The GF is quite upset, but she'll get over it.

My first move would be to dump the 12AX7 tube, and then choose from either a 6SL7, 6SN7, ECC40, or 5687 depending on how much gain is needed. Next would be to put the gain stage first and then the cathode-follower, or dump the cathode-follower altogether. I still don't know what that 330k resistor does so we'll leave it for now, but removing it might be an option. All those 10k grid-stopper resistors can likely be dumped as well, with a good wiring layout you don't need them. Then you can play with fun stuff like LED biasing on the tubes and an ultrapath capacitor between the B+ end of the transformer and the cathode of the EL84.

Well, there's this slight problem of making a push-pull amp run with a single-ended transformer...

To broadly generalize. Ultralinear: More power & dynamics, flatter & more extended frequency response. Triode: More midrange goodness & better tone, but at the expense of the above. I don't have much experience with 6SL7's or EL34's so I can't recommend those. For the 6SN7 I'd probably start with the GE 6SN7GTA, not to be confused with the GTB which looks the same but sounds a lot worse. The GE 'GTA is pretty neutral sounding and dynamic, though it's not the last word in detail & refinement. It gives a good starting point to play around with the other tubes, and once that's done you can explore the more exotic (read as "stupidly expensive") 6SN7 options. My favourite is the RCA grey glass 6SN7 for its full rich tone and large soundstage, but on some tube amps it'll make things too warm and mushy.

It's so rare and expensive that it only costs $8.50. Vacuumtubes.net is selling them for about the same price, and I recently had a dozen shipped to me for under $80 from a guy on diyaudio.com. These are not rare tubes by any stretch.

Where do these crazy rumours come from?

A quick back of envelope calculation says it should be entirely possible. I built mine for under $100 CDN, but I bought a lot of the parts used from a local surplus store. The big expenses will be the transformers, the choke, and the motor-run capacitors, that might add up to maybe $200-250, everything else is literally a few dozen dollars. I used Cat6 network cable to do all the wiring since I had a ton of it lying around. I'll draw up a schematic for the DC tube filament supply after I get mine dialed in, it's running a little higher than I'd like with the 37's, I want it to run at 5.9V-6V instead of the nominal 6.3V

Thanks! It is indeed built on a piece of perfboard/stripboard or whatever they call a board with a bunch of holes in it in your part of the world. I just drilled the holes for the sockets with some large wood bits on my powerdrill and glued the sockets in place, then put the supports & standoffs near the sockets so I don't break the board when putting in the tubes.

Yup. Except it'll be the Swedish women's bikini babes and not a bunch of butch Amazons.

New and improved, now with the wonderful 37 tube as the input. A 37 for each channel, then to an ECC40 (a dual triode) which does the phase-splitting for both channels, then to the output tubes. This is much better for Grados as it significantly lowers the gain and makes the volume knob a lot more useful. You can also use a 76 which has a tad more gain, but nowhere near as much as the ECC40. These tubes are still pretty cheap, $10 give or take $5 or so, but you might have to hunt around a bit. I think they sound better than the ECC40 as well, but I'll have to borrow a better source to be sure. My recommendations would be as follows. For Grados and other low impedance 'phones, build it with 37's. For Senns & AKG's, go with the higher gain all ECC40 version.

Other. I choose to be fucked to death by the Swedish Bikini Team. If I gotta go, I'm going with a big fucking grin my face and the best damn orgasms any man has ever experienced.

I'm trying to make sense of the Doge circuit, but either it's too early in the morning or something's really weird. It looks like a cathode-follower input to a common-cathode gain stage which then feeds the trioded output tube. Other than dropping gain, I can't figure out a reason for a cathode-follower input, and the 330k resistor puzzles me as well. It's just not making sense to me, I don't know if it's some brilliant concept which is way over my head or an amateur hackjob.

I've heard it, it's decent and performs at its pricepoint. The big problem is the electrolytic capacitor on the output which will mess up the sound, along with the 10k plate resistors on the 6SN7's in the cascode which are too low and will lead to excess distortion. Ideally, the plate resistors should be about 5-10 times the resistance of the tube's plate impedance, the Rp of a 6SN7 is about 7.7k. I'm guessing that the Chinese ripped off a 6DJ8 circuit and swapped in 6SN7's without bothering to fix the circuit. Interesting, want to post the improved circuit? There's a surplus shop in my area and I should be able to find the parts to build it.

Yup, now you gotta find a new source for Reks to buy so you can scoop up his Audio Aero Capitole.