Mic Preamps

[peAk]

Hi guys,

Haven't been on here much because I have been doing some other DIY stuff (Acoustic Panels) that isn't pedal related. That being said, about to jump back into some pedals.

Anyway, I need a better mic preamp for recording. Been shopping around and stumbled across this place: http://www.seventhcircleaudio.com/products.htm

Has anyone built something like this? If so, is it along the same difficulty as a pedal?

Any advice would be greatly appreciated. I was looking to buy a Golden Age or Focusrite preamp but if I can build something even better/cheaper, that would be great.

[RobA]

I haven't built one of those, but it doesn't look to be too different from building a pedal. You would have to deal with mains voltage levels if you were to use their power supply and that would add some complexity.

I have looked into building a mic pre and the parts aren't cheap. The transformers can be pretty expensive when you are getting small numbers of them (like one). The Cinemag transformers did look pretty good in reviews when I was reading about building one and their website has some application notes with schematics for designing and building stuff. I'm pretty sure they had one on doing mic pres.

The reason I didn't end up DIYing one is that I found a good price on the EHX 12AY7 Mic Pre and went with that. I actually really like the EHX pre. It's kinda clunky. It's kinda noisy. But, it sounds really good. Basically, it's like everything else EHX does. It's worth checking out as an option.

[JohnL]

In the pro audio world these guys get real good reviews for sound quality. The other player that is talked well of is http://www.fivefishstudios.com/ . I have not build either, I have just heard good things about them both. 

[lincolnic]

I've never used the Seventh Circle stuff myself, but there's another engineer who works at my studio that has a whole rack of their gear and loves it.

It's worth noting that if you're looking to build something for cheaper than you can buy it, remember that there are extra costs that aren't immediately apparent - you'll probably need some kind of rack or chassis to hold and power the mic pre(s), for instance.

Before I go further, I should say that I'm approaching this from the perspective of someone who makes their living as a recording engineer, not just a hobbyist. Feel free to take anything below this line with a grain of salt. 

For my money, in terms of component quality, engineering know-how, and final product, the best kits come from Classic API and Hairball Audio. They both make mic pres that are meant for the 500-series format, which (for me) is super convenient. You need some kind of Lunchbox to put them in, but you'd need some kind of chassis for the Seventh Circle stuff anyway. For the same price as two of their OneShot modules, I got a six-space Lunchbox from Lindell Audio (the 506 power).

For me, I went with the 500-series format because there are a ton of companies who make modules in that size - it's really popular. With the Seventh Circle stuff, I believe you can only use their modules in their rack, and I wanted to have more options in the future.

I've got two VP28s from CAPI and two Lolas from Hairball in there right now, and I couldn't be happier. I did an A/B with my VP28s against the API pres we have in our console, and they were basically identical. The Lolas share the input/output transformers with Neve 1073s, but use the John Hardy 990 op-amp, so they can also get very clean...they're wonderful. I believe both the VP28 and the Lola will run you about $400 for a channel.

(I promise I'm not affiliated with either company - I just really like their gear.)

Here's a build report I did for the VP28: http://www.madbeanpedals.com/forum/index.php?topic=10484.0

And one for the Lola: http://www.madbeanpedals.com/forum/index.php?topic=11069.0

I'm going to fill the last two spaces in my Lunchbox with compressors, but that's a different thread.   

[oldhousescott]

Those Lindell lunchboxes are a great value. I picked up a 6-space unit so I could have two good channels for recording. So many options now in the 500 series format.

[lars]

I got curious about microphone preamps, and found some information about the Yamaha PM1000 http://www.natedort.com/pm1000-racking/. Apparently there is a lot of information and mods available for the input channel strips, where people take them out and use them for mic pre's. If these are really based off of old 70's Neve designs as claimed, it would be hard to go wrong. You can find these on Ebay for reasonable prices.

[Leevibe]

Hi guys,

Haven't been on here much because I have been doing some other DIY stuff (Acoustic Panels) that isn't pedal related. That being said, about to jump back into some pedals.

Anyway, I need a better mic preamp for recording. Been shopping around and stumbled across this place: http://www.seventhcircleaudio.com/products.htm

Has anyone built something like this? If so, is it along the same difficulty as a pedal?

Any advice would be greatly appreciated. I was looking to buy a Golden Age or Focusrite preamp but if I can build something even better/cheaper, that would be great.

It's great to hear from you Justin. Just curious, what kind of panels do you make? I keep thinking I'm going to build a bunch of bass traps but never get around to it and/or am too broke.

[lincolnic]

Those Lindell lunchboxes are a great value. I picked up a 6-space unit so I could have two good channels for recording. So many options now in the 500 series format.

Yep, that's the one I've got as well. Best value for 500-series power, as far as I can tell!

I got curious about microphone preamps, and found some information about the Yamaha PM1000 http://www.natedort.com/pm1000-racking/. Apparently there is a lot of information and mods available for the input channel strips, where people take them out and use them for mic pre's. If these are really based off of old 70's Neve designs as claimed, it would be hard to go wrong. You can find these on Ebay for reasonable prices.

We had a pair of these at one of my studios for a while. I never got to A/B them against Neves, but they sounded alright on their own. Pretty punchy. We used them on toms a lot.

[peAk]

Thanks for all the info guys

lincolnic, I haven't done ANY research on DIY mic preamps, I just happened to stumble across a link to seventh circle from a thread on gearslutz. It's interesting to know that there are some others out there and I appreciate your input. I just have a small, home studio so I don't need something too extravagant. I was looking to spend $300-ish. I was looking at some used Focusrite ISA One, even looking at some cheaper Art Pro MPAs. Some people say Art is junk and others seem to think they good for the money. It seems like I have read so many reviews this week on preamps that I don't know if I am more educated or more confused. I just want something to sweeten and warm tracks up from time to time. I like the idea of a tube preamps because I love the tube sound but many folks think that you can't get a true tube preamp for under $1500 that's worth a crap. I have read other people argue that and say that the Art Preamps are not starved plates and do warm up the sound with the tubes. The preamps on my Mackie and audio interface are decent but just don't cut it all the time. Mainly vocals and acoustic guitar. I would probably used it on some vintage synths as well. At most, I would like a stereo/two channel preamp but would be fine with a single channel.

Rob, I did consider the EHX 12AY7 Mic Pre because I read a ton of good reviews but I also read that it's pretty noisy. Do you agree with this?

Lee, I am building some acoustic panels with some framed John Manville 814 insulation which is equivalent to Owens Corning 703. I bought 9 sheet of 2" X 24" X 48". My room isn't terrible sounding but it definitely needs some work, especially with the bass. I have watched quite a few tutorials on improving room acoustics so I am hoping that with a little trial and error, I will get some improvement.

Again, thanks for any and all input guys!

[Leevibe]

Lee, I am building some acoustic panels with some framed John Manville 814 insulation which is equivalent to Owens Corning 703. I bought 9 sheet of 2" X 24" X 48". My room isn't terrible sounding but it definitely needs some work, especially with the bass. I have watched quite a few tutorials on improving room acoustics so I am hoping that with a little trial and error, I will get some improvement.

Again, thanks for any and all input guys!

Cool! What's the cost vs the 703? Did you find it locally or online? Are you doubling up for 4" or staying with 2" and spacing off the wall?

[peAk]

Lee, I am building some acoustic panels with some framed John Manville 814 insulation which is equivalent to Owens Corning 703. I bought 9 sheet of 2" X 24" X 48". My room isn't terrible sounding but it definitely needs some work, especially with the bass. I have watched quite a few tutorials on improving room acoustics so I am hoping that with a little trial and error, I will get some improvement.

Again, thanks for any and all input guys!

Cool! What's the cost vs the 703? Did you find it locally or online? Are you doubling up for 4" or staying with 2" and spacing off the wall?

SPI, the supplier here in Houston, sells the John Manville 814 which is almost the exact same specs as OC 703. This is what they had in stock and it was $1.18 a square foot. Online wasn't really an option to me because the shipping on that stuff is pretty expensive. Luckily I was able to find some locally that had it.

I am going to do one panel 24" X 48" that is going to be enclosed in a frame that is made 4 inches wide and I will double up with two sheets of insulation. This will of course be a bass trap. This one I will have to have it off the wall with some sort of bumpers. The rest I will do like a guy I saw on youtube do where he uses 3" frames and uses 1"X 1"s inside the frame to have the insulation rest back an inch from the wall. I think I like this better because it will allow the panels to rest flush against the walls. Not sure if that makes sense? I can probably find the tutorial if I am not explaining it correctly.

[Leevibe]

Lee, I am building some acoustic panels with some framed John Manville 814 insulation which is equivalent to Owens Corning 703. I bought 9 sheet of 2" X 24" X 48". My room isn't terrible sounding but it definitely needs some work, especially with the bass. I have watched quite a few tutorials on improving room acoustics so I am hoping that with a little trial and error, I will get some improvement.

Again, thanks for any and all input guys!

Cool! What's the cost vs the 703? Did you find it locally or online? Are you doubling up for 4" or staying with 2" and spacing off the wall?

SPI, the supplier here in Houston, sells the John Manville 814 which is almost the exact same specs as OC 703. This is what they had in stock and it was $1.18 a square foot. Online wasn't really an option to me because the shipping on that stuff is pretty expensive. Luckily I was able to find some locally that had it.

I am going to do one panel 24" X 48" that is going to be enclosed in a frame that is made 4 inches wide and I will double up with two sheets of insulation. This will of course be a bass trap. This one I will have to have it off the wall with some sort of bumpers. The rest I will do like a guy I saw on youtube do where he uses 3" frames and uses 1"X 1"s inside the frame to have the insulation rest back an inch from the wall. I think I like this better because it will allow the panels to rest flush against the walls. Not sure if that makes sense? I can probably find the tutorial if I am not explaining it correctly.

That makes perfect sense. I hope you post pics when you're done. I'll be curious to know what differences you notice in your recordings.

[lincolnic]

lincolnic, I haven't done ANY research on DIY mic preamps, I just happened to stumble across a link to seventh circle from a thread on gearslutz. It's interesting to know that there are some others out there and I appreciate your input. I just have a small, home studio so I don't need something too extravagant. I was looking to spend $300-ish. I was looking at some used Focusrite ISA One, even looking at some cheaper Art Pro MPAs. Some people say Art is junk and others seem to think they good for the money. It seems like I have read so many reviews this week on preamps that I don't know if I am more educated or more confused. I just want something to sweeten and warm tracks up from time to time. I like the idea of a tube preamps because I love the tube sound but many folks think that you can't get a true tube preamp for under $1500 that's worth a crap. I have read other people argue that and say that the Art Preamps are not starved plates and do warm up the sound with the tubes. The preamps on my Mackie and audio interface are decent but just don't cut it all the time. Mainly vocals and acoustic guitar. I would probably used it on some vintage synths as well. At most, I would like a stereo/two channel preamp but would be fine with a single channel.

I've never used the Art stuff, but I've been told that they actually just hide an LED behind the tube to make it look like it's glowing. I don't know if there's any truth to that, but it doesn't exactly inspire confidence...

Unfortunately I think for $300 you're probably going to have to buy something used. The DIY projects all come in at more than that once you take the chassis or rack into account. Even the Seventh Circle stuff will probably run you about $350 for a kit and the OneShot chassis (depending on which kit you want, of course). The guys at Hairball just came out with some great kits called Elements that run about $300 each, but you'll need a 500-series rack or Lunchbox to make use of them.

A Focusrite pre will probably be much better than your Mackie, and likely better than the Art stuff as well. If it fits in your budget, I'd say you could do a lot worse than that.

[RobA]

...
Rob, I did consider the EHX 12AY7 Mic Pre because I read a ton of good reviews but I also read that it's pretty noisy. Do you agree with this?

I wouldn't say that it's really noisy. The noise level kinda depends on what you are doing. I just did a bit of a test to try and quantify it a bit. I used two mics, a Sennheiser e845 and an Audio-Technica AT3035. I ran the mic into the mic input on my MOTU Microbook II interface for the comparison and into the 12AY7 then into the line in on the MOTU as the test. It's not ideal, but it does give an idea of what's going on.

For the e845 using the MOTU's pre, I have to boost the input trim to max to match a moderate level of gain on the EHX and get a good recording level. Doing that actually causes the MOTU to have a bit higher broad spectrum noise level than 12AY7. They sit at about -80dB and -86dB respectively. But, the EHX also has a single -72dB peak at 120Hz.

For the AT3035 the story is much the same, except that the input gains of both pre's can be set much lower so the overall noise levels are much less to begin with. The EHX does still have a prominent noise peak at 120Hz.

But, and this probably has more to do with the perceived noise than the stuff above, with both mics, I'd say the MOTU's pre is more flat and colors the signal significantly less. I actually like the way the EHX colors the output, especially with the AT3035, but I could easily see that it wouldn't be ideal on everything you might want to record.

One other consideration is that I haven't changed the tubes from those that came with it. You could probably alter the coloration and improve the thing overall with some better tubes in it.

[sonarchotic]

I've been meaning to build this little project since I saved it a while back but I haven't yet. For such a simple looking project it seems worth building just to hear it before going out and buying a pre-amp. http://www.audiomasterclass.com/the-famous-5-preamp-everything-you-need-to-know#.VAuyAf8g_IU