Suggestions for a Tube Pre-Amp / Saturator?

[m00dawg]

I couldn't decide if this goes in Parts or Design Concepts since it's maybe a bit of a stretch either way, but I'm thinking about building or buying a tube pre-amp / saturator. I found Ableton Live's software version and while it's good, I guess I'm just old school and would prefer to get analog warmth from a real analog device. Or maybe I'm just being intentionally difficult :)

I've been looking at some tube-amp solutions, including kits from the likes of PAiA and was curious as to if anyone can recommend anything, or if they have found that software solutions (like those found in Live) actually do a good enough job?

The current application is to put it in the master chain, trying to approximate one of Live's "warming" mastering presets. After that I was thinking of using it for various synths (including my fleet of MidiBox gear, as well as my NES and GameBoy) to add warmth where needed. Finally, I thought about using it for my turntable after my phono pre-amp stage to see if I can add just a bit of warmth when using it as a normal (unsaturated) pre-amp, depending upon what solution I went with.

Thoughts? What do folks around here use to add tube-like analog warmth and distortion?

[JRock]

I built a 5532 based mic pre and it gets pretty crunchy if I turn it up. It's pretty warm. The first thing I ever built was a Paia tube pre... needless to say it didn't work :getlost: That's entirely due to my own ineptitude - don't let that be a reflection on Paia.

I'll see if I can't find this 5532 pre ...

simple 5532 mic pre

I just saw that it has a pcb... I just knocked it up on pad-per-hole board.

You could probably control the gain on it if you used a pot for R4.

Not a tube pre... but easy and warm.

[m00dawg]

Ah, actually, that's not too far off from a CMoy headphone amp design from what I can tell (which I have built before). I'm guessing the IC is an op-amp of some sort so I suspect the magic is in the choice of op-amps in this case?

[nILS]

I can highly recommend toying with some of these: http://www.tube-town.net/diy/lov/lov03-bananabooster-eng.html

Cheap, easy, low voltage, still nice :) You'll want to adjust the input impedance though as it's geared to'rds guitars.

[m00dawg]

Thanks guys! I've done some more research and unfortunately just added confusion for myself :)

I'm having trouble figuring out the differences between tube pre-amps and buffers.

What is the difference between a tube buffer (something like this), the starved-plate design (like the PAIA and, I think the design nILS recommended?) and full-plate (like a DBX386)?

I think more importantly than listening to audio sources (like my turntable), I really want to add color and warmth (harmonic distortion I guess to sciency types) by using it in a send/return sort of way (bouncing tracks from Ableton Live out to whatever magic box I go with and back in).

In terms of DIY, I also found these guys. No idea how they compare to other designs but thought I'd share.

Edited August 20, 2011 by m00dawg

[nILS]

What is the difference between [...] the starved-plate design [...] and full-plate?

A few hundred volts.

[m00dawg]

A few hundred volts.

Haha, yes. I was more referring to the differences in sound, specifically when using tubes in a buffer or pre-amp? Most of the unfavorable reviews for the Paia refer to a dirty, as opposed to truly warm, sound.

But I'm not sure how that matters in something like a tube buffer (the first link).

[nILS]

When it comes to tube preamps/classy tube sound/analog warmth you'll get 11 different opinions for every 10 guys you ask. I'd suggest visiting a well sorted music store or trying to find some A/B clips online.

Assuming you haven't done any tube or HV projects, I'd suggest starting with a low voltage one and pretend it's HV - even if the sound may be a lot different from an incredibly cool awesomely hot running tube :flowers:

Some hundred volts through your body fizzle quite a bit and make you jumpy for the rest of the day. Or dead.

[m00dawg]

Indeed as far as building anything, I'd probably build a low voltage project. I assume, just like building a PSU, doing any high voltage just takes common sense and diligence but no need to push the envelope.

I haven't found many A/B tests online except for the Grant Fidelity one. Though it was a YouTube (and seemed to be biased towards the Grant Fidelity stuff), it did indeed sound warmer. In this case, it was being used in an effect loop on a guitar amp.

I'll keep looking for A/B tests. Local music store is a good idea but while they have a good amount of synths, I didn't see a lot of tube effect processors that weren't strictly part of guitar amps.

[m00dawg]

So I did more looking around and I think the Grant is driving the tubes somewhere between 100-250V according to some pics I was able to find of the inside of the unit and mention of a transformer. Compared to the pre-amps I was looking at, it's great for the price, but has no way to drive the inputs hot or anything like an actual tube pre-amp. The Grant is not a rackmount solution either and anything I create I could retrofit into a rackmount. So that's a minus. Another minus is that the tubes use are 6SN7 instead of the 12..7 ones commonly used in guitar amps and things.

*shrug*