[Sodacose]

BAM:

Aluminum w/ walnut sides

Just arrived today: gorgeous case! As you can see by the ending price on the auction, it was a steal. Now what do I do with this?

I could use a stereo preamp and/or a new DAC. I'm thinking this bad boy needs some tubes and iron sticking out of the top. Anyone have a good preamp design they're willing to share?

-I don't need much gain at all (my power amp has 330k input impedance if it makes a difference).
-I'm going to be building a new DAC somewhere down the line so the output of that is undetermined ATM
-It will also be used with a Bugle phono preamp (I read somewhere it outputs like 3.4V pk-pk)
-Headphone output a bonus!

If there's room the DAC may go into the same enclosure as the preamp (maybe I'll do a Bantam just to tide myself over). Anyone know if I can get away with unity gain? I'm comfortable with raw schematics and PTP wiring, but I'm looking for something that does not have hard-to-source tubes.

This case is just too perfect for a tube pre/amp to sit unused!

 

[digger945]

I've seen a case that looked very similar to this one, and costing way more than this one too.
Great looking case, and at a price too good to pass up, think I'll go ahead and get one myself.
If it were me, it would have to be another Aikido tube project of some sort, and if money permitted, with a TVC/AVC type input attenuator.
Thanks for the link, these guys are not far from where I grew up.

EDIT: It would appear this seller does not have more of these cases FS. Bummer.

 

[Sodacose]

Quote:

Originally Posted by digger945 /img/forum/go_quote.gif I've seen a case that looked very similar to this one, and costing way more than this one too. Great looking case, and at a price too good to pass up, think I'll go ahead and get one myself. If it were me, it would have to be another Aikido tube project of some sort, and if money permitted, with a TVC/AVC type input attenuator. Thanks for the link, these guys are not far from where I grew up.

There were originally two listed (one slightly more shallow). I just e-mailed the seller to see if they are producing these things or whether it was just some kind of one-time surplus deal. I will let you know!

The wood looks much better in person than in the pictures.

I've been considering an Aikido for some time now actually, but my PTP bug has really gotten going of late. I guess I could always do an Aikido PTP, but it would be a shame to not take advantage of those nice PCB's they sell.

 

[compuryan]

You could build the RAKK DAC, kits are available here:
K & K Audio - Lundahl Transformers, audio DIY kits and more

 

[Sodacose]

Quote:

Originally Posted by compuryan /img/forum/go_quote.gif You could build the RAKK DAC, kits are available here: K & K Audio - Lundahl Transformers, audio DIY kits and more

Wow; just skimming the info, that looks like a nice DAC. I should have mentioned I'm thinking a budget of about $500 though. That RAKK design is not fooling around!

 

[ericj]

Wow, that case is old. I've seen a tape hiss filter built into one of those - from the seventies.

 

[linuxworks]

I like that old style! I might try building one similar.

I was around in the 70's when wooden end panels were the rage. properly done, it can still be a good effect.

(if you dont' want that box, sell it to me! I am building a beta22 right now)

 

[olblueyez]

Nice tube amp with some tubes and tranny's sitting up top and some nice silver knobs on the front.

 

[m0b1liz3]

Your link is dead.

 

[Sodacose]

I'll post a couple pictures when I get back.

I heard back from the seller and unfortunately this was old-stock (probably is the same cases used in the 70's).

Anyone have any experience with 12B4 circuit designs for preamps? I have heard good things about them and I'm trying to find a proven schematic. With the iron costs from the looks of most of them though, I may just end up leaning towards an Aikido. Choices, choices...

edit: Any Hagerman Clarinet users here? Looking at the schematic, it doesn't seem too tough to be done PTP and I love my Bugle.

 

[pistolsnipe]

modded xbox -> xbox media center

 

[Sodacose]

Alright, I'm looking at this Hagerman Clarinet schematic here.

Can anyone help me see what's going on with the pins on the two 12au7's? Looks like two tubes per channel, but I'm trying to see how this all fits together. I see that both channels use one-half of each triode but the heater config has me a little stumped. Does the heater center tap tie to ground? I then take pins 4 and 5 from both tubes and run them all (4) in parallel?

This looks like a nice candidate for a PTP build and the iron comes out to being fairly inexpensive (vs. a choke designed PS). Plus I would end up with three glorious tubes protruding from my case.

 

[krmathis]

β22 maybe, or a nice DAC...

 

[Sodacose]

Quote:

Originally Posted by krmathis /img/forum/go_quote.gif β22 maybe, or a nice DAC...

I know it's been discussed before, but do HP amps make good line-stages? I can't seem to find a definite answer and have read as many threads on the board as I could find about it.

A headphone amp will have much more gain than I need of course. But will the low output impedance of a HP design cause any problems? I guess there would be higher current, correct? But with the parts voltages that are common to most designs that shouldn't hurt anything I would think. With the higher current, is there an issue with creating stronger magnetic fields?

I am still in the learning process as far as electricity goes so please forgive me if any of these questions are far off the mark!

 

[linuxworks]

I'm using my phones amp (pimeta) as a preamp before my speaker amp.

in phones mode, I use active ground (when its there). in preamp mode, I take ground from input ground and let the 3rd channel just do nothing.