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recommended DIY tube mic preamps?
Old 30th May 2015
  #1
Here for the gear
 
🎧 5 years
recommended DIY tube mic preamps?

looking for the best shot for the money, the most cleanest fullest alive-st sound possible without spending over 300 bucks

thank you kindly for your time and help
Old 30th May 2015
  #2
Lives for gear
 
Richard Crowley's Avatar
 
🎧 10 years
$300 for a single channel?
Are you looking for a kit, or are you looking to completely roll your own from scratch?
Old 31st May 2015
  #3
Here for the gear
 
🎧 5 years
i can roll my own i dont need a kit i just want what's best for the money

yeah single channel

probably some sort of clone is the best bet I'm expecting someone to recommend but I'm open to anything
Old 31st May 2015
  #4
Lives for gear
 
🎧 15 years
Hi
The main cost for a mic preamp is in a GOOD mic transformer and an output transformer (if you want to use one there too) then power supply parts, switches and box. The valve(s) and passive components around the circuit are relatively cheap in comparison.
Find the transformer(s) first.
Matt S
Old 31st May 2015
  #5
Lives for gear
 
ruffrecords's Avatar
 
🎧 10 years
Check out my EZTubeMixer design here:

EZ Tube Mixer Support Thread

PCBs are available.

Cheers

Ian
Old 31st May 2015
  #6
Gear Maniac
 
theaterguy's Avatar
 
🎧 5 years
How about NYD's One-Bottle Preamp or Mila-1 on groupdiy.com? I built a point-to-point one-bottle a few years back and I like it a lot. Cinemag transformers were the biggest cost, other parts just about 50€ or so.
Old 31st May 2015
  #7
Gear Head
 
🎧 5 years
Ez Tube Mixer's mic amp part is probably the only one you could build for this money and get sound you want, along with all controls needed in modern studio. Pcb can be easily modified from SRPP to mu follower output, it will be cleaner driving typical 10k or higher loads, output transformer is optional too.
I guess you know making it with well designed pcb like this one requires less material and work, controls could be hard wired to 19" rack, etc. Many of us really like how it sounds, so is well tested and supported.
I built quite a few highly regarded classics point to point which takes a lot more work, knowledge, material that is hard to get today, sometimes experiment a lot because not many people do it. You are on your own with projects like that... This is why i recommend this preamp without hesitation.
Old 31st May 2015 | Show parent
  #8
Gear Head
 
🎧 5 years
Quote:
Originally Posted by theaterguy ➑️
How about NYD's One-Bottle Preamp or Mila-1 on groupdiy.com? I built a point-to-point one-bottle a few years back and I like it a lot. Cinemag transformers were the biggest cost, other parts just about 50€ or so.
I helped a friend build point to point 6SN7 One Bottle which sounds pretty good, although Ian's seems more flexible at least. But 50€ was psu part with transformer only, 19" chasis 70€, both signal transformers with the rest of material (i gave him some) 150€, at least 50€ more for shipping/customs because we couldn't get all at one place in EU. Simple but well built preamp like this costs more like 400€ with engraving and we used no "audiophile grade" material.
Of course it can be done for like half the price or less if he already had some material and didn't use 19" chasis.
Old 31st May 2015
  #9
Gear Maniac
 
theaterguy's Avatar
 
🎧 5 years
Yes, mine chassis was picked from junkpile and it is still without an internal 48V phantom. But it's quiet enough to track vocals with a ribbon.
Old 31st May 2015
  #10
Gear Head
 
🎧 5 years
Nice that you could put old material to good new use, i like to do it too when possible. Seems like a phantom, attenuators/gain controls, psu and grounding add up, mechanical part even more.
Old 1st June 2015
  #11
Lives for gear
 
🎧 10 years
You could use IC's to avoid the need for the input/output transformers. I mean, if you just want tubes, that's conceivably an option. But I'll be honest with you. If given a choice between tubes and transformers, I'll take the transformers. I think they add more to the sound. I describe it like this: Tubes give a sound its glassy sheen. Transformers give depth and fullness. To be honest, getting some transformer mojo into a SS signal sounds darned good to my ears. Yes, the tubes add those harmonics, but transformers seem to add some pleasing dynamics... at least to my ears. A lot of times people attribute everything to the tubes, but I grew up with a hi-fi stereo from the 70's. It proudly proclaimed it's solid-state design. However, it had transformers, and even to this day, that's the sound I reference in my head when trying to pick out which unit has a transformer and which one doesn't. I describe it as a woofy boomy kind of compression that almost sounds like an expansion (because it distorts and draws attention to itself when pushed hard), It's more recognizable in the bass frequencies. (Curious if any other geekslutz can validate or expound upon why this is my impression... in technical terms. I believe that low-frequency signals tend to load the core of the transformer more and create a short-lasting distortion on both ends of the sine-wave, similar to what DC current does. Does that make sense?).

But what if I told you that you could find you a tube preamp, prebuilt, not starved-plate, costing less than $200? Check out an Electro-Harmonix 12AY7. It's a tube mic pre (with XLR in and out) in a pedal format. It's not starved plate (it runs at 200V). And you can find used ones under $150. For awhile I really wanted to try one, to get the experience with tubes that I had with the SS hi-fi with transformers to really hear the difference between tubes and transformers (they typically go together). I haven't done it myself though, in part because I'm more sold on the transformers. However, I still think it'd be an interesting thing to toy around with and the price is right. Actually, since my Drip Opto6 (LA2A "clone") is up and running, I was just thinking that something like the 12AY7 might be a nice compliment to it, since the LA2A already has enough gain and won't demand a whole lot from the preamp.

The only real complaint I've seen on the 12AY7 is that some units are noisy, but in every instance I've read about noise, the guys who could wield a DMM and soldering iron were able to open it up and resolve it. I don't remember all the details on that though, so you'll have to Google it yourself if you happen to have issues.

Last edited by Grimace; 1st June 2015 at 09:30 AM..
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