Heavily Modified altec 1591a Mic Pre With Compressor

Description

Heavily Modified altec 1591a Mic Pre With Compressor.
Thinking about buying a k RS124 or overpriced 436C? Or looking for a world class mic pre + compressor? Consider this ground up, heavily modified and restored one of a kind mic pre with an incredible array of unique features you will simply never see ever again. Two years in the making, we present to you the coolest new mic pre/compressor on Reverb: this heavily modified, one of a kind Altec 1591A!
So try to wrap your head around how cool this feature is:
My amazing tech somehow figured out how to modify this unit to accept TWO of the famous plug and play Altec can preamps into this single unit (the silver can and purple can on the back). What does this mean? It means you now have two separate pre's on two separate inputs (one on a Switchcraft pigtail and the other on a chassis mounted switchcraft XLR input jack as shown). There is a pair of world class Altec pre's in one box! This has never been done before and will certainly never be seen again, totally one of a kind. The compressor card was completely rebuilt, new power cords, new caps and wiring, new tooology revisions and essentially a fresh modern redesign of a classic which has kept its warm tonal characteristics.
The unit has two power cords for this reason too, one of which also now feeds custom phantom power rails and a new white LED indicator light that shows if 48V+ is engaged or not. The front two panel knobs on the left are now input and output. It is essentially a two input mono microphone mixer, as you can use both inputs at once with a single output! One of a kind awesomenesss.
Each input has very different gain and tonal characteristics but both are quite colorful, clean and open. Neither oscillate or have any noise at all and have been fully rebuilt. The overall gain is greater than that of an RCA OP-6 too, yielding around 94db of overall gain(!!!). To put that in perspective, the Neve Portico is around 65db and the OP-6 is 72. Neither are suitable, imho, to power a beefy gain-hungry ribbon like an RCA 44.
Side note: I was told by some world class techs this could not be done btw ;)
What’s included in this listing:
This listing comes with two physical units, the aforementioned, a heavily modified unit with separate phantom power PSU in excellent condition. The other included unit is the non-functioning donor unit we took the compressor card out of. The donor unit can still can be turned into a cool little dual input line amp if desired as it still has the rest of the guts intact... sans the compressor card. The donor unit alone is worth about 800+ bucks. With the modified unit outperforming a 436, the price for both is a no-brainer.
THE VERBOSE AND DETAILED DESCRIPTION:
The first thing we did was to add phantom power. That pic of the light tan PSU (power supply) is the independent plug for phantom, as it has its own power supply separate from the chassis power plug. We used the redundant voltage toggle switch on the back to be repurposed to be the 48v+ toggle switch and installed a white LED under the switch (as shown) so you can see if it’s providing power too.
We then ripped the compressor card out of the donor unit and installed it in this guy and tweaked for optimal performance. All the red caps you se on the card are new. The compression slope is a bit wider and more useful now too. It’s still a nice and slow “vari-mu” compression style just like it’s big brother, the 436 but definitely a different animal. I find it more useful as it occupies the range of the most desirable ratios for vocals and instruments.
The gain and tone of this mic pre spanks the hell outta the ,000 boutique OP-6 and similar boutique pre’s with a whopping 95+db of overall gain! Your ribbon mics will be well equipped to give you the most open sound stage you’ve ever heard from a preamp. Dare I say the tone is nicer than the RCA’s as well? It’s factually far more versatile with two independent internal preamps modules in one box. Quiet noise floor and huge headroom. I was told this was quite a feat in itself to recap the unit to achieve such a quiet noise floor. This unit also does not oscillate at high levels either, pretty much clean all the way to the top.
The coolest modification:
The purple and grey cans are the actual isolated preamps in an external plug and play format unique to Altec and many of their other units of that era. Altec designeded these to work interchangeably with the 1591A and their other mixers and are highly sought after today. However they were never designed to work at the same time like this. We were able to modify the signal path so that BOTH mic preamps can be used and blended between, providing two totally unique tonalities in one amazing mic pre. Think about it, two mics on a single source with blendable outputs. Unheard of. The outer shell was pryed off and all components inside were replaced and modified too. To our knowledge, this has never been done before, making this a true one of a kind twist on a classic. This unit utilized both the 1588A isolated transistor preamp AS WELL as the 1588C preamp! Having two totally different mic pre’s in one is quite the hat trick and a great way to color your sound easily as you track, similar to the color modules by DIYRE but by utilizing multiple vintage holy grail Altec components at the same time.
We also added a Switchcraft pigtails for I/O on the back and recapped the entire unit (where needed) with the highest end audio components. We replaced the terminal strip with new parts and swapped the VU meter which was inoperable at the time we got it. We also switched out the ugly knobs to nicer looking EMI style chickenhead knobs from a Gates unit of that era. Lastly, we swapped the faceplate for a mint one that has no scratches.
PRICING:
The work alone cost me over 00 and each unit cost me a G so.... do the math. Since a pair of stock 436C's are k alone (modified RS124’s go for 3k+ each), this is priced to move. I love this unit but we are expanding our studio and have to sell off some of our more special gear to buy our upcoming LFC desk. You definitely can’t beat this price for a rare and unique unit such as this; a real crown jewel mic pre for any pro studio.
Thanks for looking~ stay safe out there