Alembic Guitars Club

Connecting => Miscellaneous => Topic started by: garth4664 on September 30, 2018, 09:37:37 PM

Title: Dual regulated power supply with active mixer circuits
Post by: garth4664 on September 30, 2018, 09:37:37 PM
Hello club members,


Hope it’s ok to post here. I’ve been working with local Australian luthier Tom Konig on a few projects and just wanted to share with the club one of his creations. He’s been building me a 15 string bass that requires a power supply. I asked him to use Alembic voltages and 5 pin setup so that I can use the new bass with my series 1, 2 and custom series instruments, thinking that I would be unlikely to play a full set on the 15. He came up with this work of art. It’s a twin stereo power supply, with dual regulated power outputs. Instead of the summing resistors there are twin active buffered mixer circuits for running mono mode. Not using summing resistors to run mono seems to really improve the mono outputs, and by running dual power supplies I can run 2 basses and up to four amps (or two mono channels) from one box. All the jacks and plugs are neuteric.Will post photos. It also looks very nice!
Title: Re: Dual regulated power supply with active mixer circuits
Post by: garth4664 on September 30, 2018, 11:58:52 PM
Picture of dual power supply
Title: Re: Dual regulated power supply with active mixer circuits
Post by: garth4664 on October 01, 2018, 12:01:14 AM
Picture dual power supply and Alembic blue one
Title: Re: Dual regulated power supply with active mixer circuits
Post by: garth4664 on October 01, 2018, 12:02:29 AM
Yes, that’s two series basses being powered simultaneously
Title: Re: Dual regulated power supply with active mixer circuits
Post by: garth4664 on October 01, 2018, 12:14:43 AM
Last one for good measure, the back
Title: Re: Dual regulated power supply with active mixer circuits
Post by: garth4664 on October 01, 2018, 12:45:10 AM
Ok after a good afternoon using this new power supply and A/B testing my original ones I can’t understand why the standard power supply didn’t use an active mixing circuit instead of summing resistors. It’s obviously louder without them, but even adjusting the gains back to the same level this is definitely clearer too... do the in-2 modules have active mixing circuits for mono out. I feel like I’ve been missing out on this sound :)
Title: Re: Dual regulated power supply with active mixer circuits
Post by: mario_farufyno on October 01, 2018, 03:36:58 AM
Great job!
Title: Re: Dual regulated power supply with active mixer circuits
Post by: goran on October 01, 2018, 06:07:27 AM
That's very nice. And looks nice too.
Title: Re: Dual regulated power supply with active mixer circuits
Post by: JimmyJ on October 01, 2018, 09:07:43 AM
Garth,

Nice build!  Do you know if he hand-built the power supply sections or used pre-made modules?  Is it a quiet fan?  Very cool piece of custom kit.

As far as your summing question, it's up to the individual...  Passive summing is theoretically the cleanest way to mix two audio signals together.  There are currently many "passive" mixers sold (some surprisingly expensive) for the purpose of mixing down multi-track ProTools outputs.  Usually simple circuits of summing resistors followed by a buffer amp to regain any loss of level.  The thinking is that the least number of additional components in the signal chain will add the least amount of noise and coloration to the sound.

That said, on certain occasions in the past I have had the luxury of recording the bass in stereo and then slightly panned the two channels left and right.  This makes the bass appear to be mono but opens up some higher overtones that otherwise cancel.  It's a big sound which takes up a lot of space in the track so not always appropriate.  Of course, you're talking about your 15-string bass so you KNOW what a big sound is.   :)

Jimmy J 
Title: Re: Dual regulated power supply with active mixer circuits
Post by: garth4664 on October 01, 2018, 02:27:37 PM
Hello Jimmy and friends,


Yes the whole unit is hand built including the custom case which he cnc’d in his workshop here in Canberra. There is no fan, that’s just a stylish vent. It’s got a regulated power supply so the voltage is nice and stable. And yes I think some of the high frequencies you are describing are audible now, the sound is definitely bigger! Have a look at Tom Konig’s website if you haven’t checked him out. Alembics and Konigs are it for me, no other basses will do (the blue 12 string is mine). Jimmy you would sound huge on this 15, it’s like a grand piano.


Thanks for the nice words, I’ll let him know you guys appreciate what Tom does.
Title: Re: Dual regulated power supply with active mixer circuits
Post by: hammer on October 01, 2018, 03:15:37 PM
Looks VERY nicely done!


A few questions: Does he make a rack mount version? Does the power regulation let avoid using a power regulator (could I drop the Furman and lose some weight) ? and what would be the cost for something like this?



Title: Re: Dual regulated power supply with active mixer circuits
Post by: garth4664 on October 01, 2018, 08:00:16 PM
Hello Hammer,


Could possibly fit in a rack, you would have to check with Tom. He will make a few of these for me but I think he could be persuaded to do a little run.


I tthink you would be able to safely get rid of the power regulator for powering your bass, but you may want to keep one for your amps.


On cost, you would also have to check with Tom. It’s all hand build and hand designed but the quality is unbelievably good so it’s not cheap. I wouldn’t want to plug my instruments into a cheap power supply :)


Cheers,


Garth
Title: Re: Dual regulated power supply with active mixer circuits
Post by: lbpesq on October 01, 2018, 09:32:34 PM
I didn't notice a fuse, like on the Alembic Blue Box.  Is there an internal fuse, or some other protection circuit?

Bill, tgo
Title: Re: Dual regulated power supply with active mixer circuits
Post by: garth4664 on October 01, 2018, 09:50:15 PM
Hello Bill the good one, the fuse on the dual power supply is built into the kettle cord plug, just on top of the cord in the photo above. Tom actually added the fuse to this particular Alembic supply too for me last year, it was an old one without a fuse before that.
Title: Re: Dual regulated power supply with active mixer circuits
Post by: lbpesq on October 01, 2018, 10:27:51 PM
Ah, technology!  Is it an actual replaceable fuse or a circuit breaker?  Very clean and professional looking unit.

Bill, the guitar one (who wouldn't presume to assume the mantle of "the good one")
Title: Re: Dual regulated power supply with active mixer circuits
Post by: garth4664 on October 02, 2018, 02:33:25 AM
Hello Bill, it’s just a fuse, but built into the 3 pin power socket. Yes agree on professionalism of the unit...Tom Konigs work is amazing, he builds everything from scratch except for tuning heads. On basses he builds all the pickups, electronics, mills the bridges etc. he also makes the knobs.


The box for the power supply was Designed by Tom in CAD, Cnc milled in his workshop , folded in his workshop, powdercoated in his workshop etc. All of the screws have captive nuts. It’s a work of art in itself. He bought a new folding machine just to get the accuracy right. Last year he redesigned and rebuilt his milling machine when he decided the accuracy wasn’t good enough to make world class bass bridges from billet brass.


It’s a level of attention to detail that few builders ever reach (Alembic of course is one of the others)



Title: Re: Dual regulated power supply with active mixer circuits
Post by: keith_h on October 02, 2018, 06:11:51 AM
Looks VERY nicely done!


A few questions: Does he make a rack mount version? Does the power regulation let avoid using a power regulator (could I drop the Furman and lose some weight) ? and what would be the cost for something like this?


This unit regulates the DC power to the bass not the AC power. Your Furman provides regulation, surge and over/under voltage protection for the AC power so no one cannot be substituted for the other.
Title: Re: Dual regulated power supply with active mixer circuits
Post by: edwin on October 03, 2018, 08:19:03 PM
Looks VERY nicely done!


A few questions: Does he make a rack mount version? Does the power regulation let avoid using a power regulator (could I drop the Furman and lose some weight) ? and what would be the cost for something like this?


This unit regulates the DC power to the bass not the AC power. Your Furman provides regulation, surge and over/under voltage protection for the AC power so no one cannot be substituted for the other.

Most Furmans do not provide actual regulation, i.e. a variable input voltage results in a stable output voltage. They provide some protection, but most are just glorified power strips.
Title: Re: Dual regulated power supply with active mixer circuits
Post by: keith_h on October 04, 2018, 07:48:33 AM
Looks VERY nicely done!


A few questions: Does he make a rack mount version? Does the power regulation let avoid using a power regulator (could I drop the Furman and lose some weight) ? and what would be the cost for something like this?


This unit regulates the DC power to the bass not the AC power. Your Furman provides regulation, surge and over/under voltage protection for the AC power so no one cannot be substituted for the other.

Most Furmans do not provide actual regulation, i.e. a variable input voltage results in a stable output voltage. They provide some protection, but most are just glorified power strips.

I use a Furman AR-15 II in my bass rack. When Brian mentions voltage regulator and weight I assume he is using one or a similar model. However as you say the normal Furman stuff is really nothing more than a power strip protect by a metal oxide varistor.