I just completed a Drip REDD47 pre-amp last weekend. I've been playing around with it to test it out and it's really nice. I'm actually going to build two and sell them so that I can afford to buy one for myself, so if anyone is interested let me know. I'd keep this one if I could afford to. It uses nice (and expensive) Sowter reproduction transformers, and a ginormous power transformer.
 
It's an all tubes all the time pre-amp with tube based power section and autio path. The audio path has an EF86 and AX7. I implemented the low cut, boost, gain/fine gain adjust, and DI options. There's no 48v provided by the board, it only provides the means to switch it into the path, so I didn't implement that, though all the parts are on the board if you wanted to add it internally. Best to just use an external one, which will be just as good as anything I'd put in the box. 
 
Here's a little test I did with it. This is drums, two guitar parts and bass. The guitars are just mic to pre-amp to converters. The bass is using the pre-amps DI, then the converters. I used a Blackfinger comp pedal on guitars and bass, and an EH Cathedral Reverb pedal.
 
http://www.charmedquark.com/Web2/TmpAudio/REDDTest4.wma
 
In the mix I have a tiny bit of EQ. There's a little compression on the master bus, just bouncing the needle on the biggest hits. There's no other processing or automation or anything, so it's almost completely as recorded. Here are some bass DI samples, which are an Amer. Std Jazz directly into the DI, no other processing on the way in or afterwards. One is more kneck oriented and the other more bridge oriented.
 
http://www.charmedquark.com/Web2/TmpAudio/ReddBass1.wav
http://www.charmedquark.com/Web2/TmpAudio/ReddBass2.wav
 
Here are some pictures of the build. It's all very carefully done.
 

 

where's the like button?  Oh, that is FB.

Looks real sweet.

@

Updated the sample above to one where I was being more careful about guitar hum and gain staging.

Looks like real nice workmanship!

The clip sounds sweet.


best regards,
mike

It's for sale if anyone wants it. I need to sell this one, and then one more, then I can buy one for myself.

I finally got a little time to try to do a better sample using this guy:

http://www.charmedquark.com/Web2/TmpAudio/REDDTest4.wma

The guitars are SM57 -> REDD -> converters. The bass is REDD DI -> converters. There's wee bit of EQ on the guitars and bass, and a wee bit of compression on the master buss.

Nice sound.

I built a stepped attenuator for this guy to replace the standard gain potentiometer. Most everyone uses a pot since no one makes the sort of attenuator that the original design used. You have to build them by hand, which is pretty dang tedious. It looks like a old rotary airplane engine when it's done. I only used 11 of the twelve positions since those like up perfectly with the 0, 10, 20, ... 100 positions on the silk screening.

The attenuator was a help. It didn't lower the noise floor, but it maintains a very consistent noise level as gain is increased, which the gain pot scheme didn't. I updated the original post with some bass DI samples.

I did another sample to show off these guys. Here are two short snippets of drums. One is the original, and the other is just run out through the REDD47, and then matched in volume. It's pretty amazing the nicerizer aspects of these things.

You'd swear it was EQ'd, but it's not. It seems to suck up some of the rumbly lows, and it provides a nice, saturated boost in the nice part of the low end (above the rumble, below the mud) and in the high end. The result is a cleaner, much nicer sounding track. It's pretty amazing that a pre-amp would do that much. But, it's a vintage design, more oriented towards being euphonic I guess than accurate.

http://www.charmedquark.com/Web2/TmpAudio/ReDDDrumsOrg.wav

http://www.charmedquark.com/Web2/TmpAudio/ReDDDrumsProc.wav

And here's a bass DI track of a very different sort of vibe. It's a killer bass DI definitely. This is straight in, bass to REDD DI, to converters. Nothing done on the way in or afterwards.
 
http://www.charmedquark.com/Web2/TmpAudio/REDDBass3.wav