ADA Depot - A Forum To Support Users of ADA Amplification Gear

Non ADA Gear => Rack Gear => Topic started by: kawai2g4b on February 03, 2014, 11:00:56 AM

Title: Soho Acoustics Qtr-1 tube preamp questions
Post by: kawai2g4b on February 03, 2014, 11:00:56 AM
Okay guys, I tried several forums to gather info on a Soho Acoustics QTR-1 preamp and have had no luck.  It is supposedly almost if not identical to the KittyHawk Quattro preamps.  I need a schematic for it at the very least.  Anyone have any experience with these?

I intend to use this pre with my fuzzes as my seperate stoner/doom/acid rock setup with a little thrash capability thrown in as my MP-1 is not as friendly to fuzz as I thought it would be.
Title: Re: Soho Acoustics Qtr-1 tube preamp questions
Post by: rnolan on February 03, 2014, 06:22:11 PM
There's some raves here (http://www.harmonycentral.com/t5/Amps/Soho-QTR-1-Preamp-Kitty-Hawk-Quattro/td-p/3463291), from what they are saying it would appear to be a good unit for what you want it for. 4 x 12AX7s so plenty of gain.
Title: Re: Soho Acoustics Qtr-1 tube preamp questions
Post by: kawai2g4b on February 03, 2014, 10:38:39 PM
Yeah, though I believe mine needs a re-tube, definitely dark and loose sounding.  And it really does sound great with fuzz, really tames and focuses some of my wilder glitch fuzzes...which is what these 80's era designers really intended for it to do.  :o

I'm going to look into some slightly brighter tubes and compare with the Amperex tubes that this thing already has, either way, the clean/crunch mode needs a little more treble prescence.
Title: Re: Soho Acoustics Qtr-1 tube preamp questions
Post by: rnolan on February 04, 2014, 10:24:50 PM
The Boogie STR 12AX7s would be a good choice IMHO, nice and bright, plenty of gain, low noise, very tight.
Title: Re: Soho Acoustics Qtr-1 tube preamp questions
Post by: kawai2g4b on February 13, 2014, 11:50:16 PM
I have not made the tube swap yet but I went ahead and hooked my my entire doom/psych/funk/retro pedalboard up to this thing.  First of all, the crunch and clean channels love my pedals with the Mosvalve power amp (not so much the hotter channels, as expected).  This thing is a keeper after all, though a well thought out mod wouldn't hurt.  The past reviews about these are spot on, tone controls are not very flexible but the preamp sounds great anyway, definitely has a Mesa vibe about it and does its part to really project my sound forward.  Right now I am pretty satisfied with it, will try out the Roland GP-8 with it tomorrow  >:D.
Title: Re: Soho Acoustics Qtr-1 tube preamp questions
Post by: rnolan on February 14, 2014, 08:27:54 PM
If its got a Mesa vibe to it those STR tubes will probably work very well, lots of gain though so may be quite a handful cranked  >:D
Title: Re: Soho Acoustics Qtr-1 tube preamp questions
Post by: kawai2g4b on February 15, 2014, 10:51:08 AM
Oh, but when has that ever been a problem?  >:D >:D >:D :metal:

That being said, I just need to get the tone a little clearer than it is right now.  If I ever use this in a PFunk tribute band, I need it to cut through a little bit better on its own without engaging my pedals.
Title: Re: Soho Acoustics Qtr-1 tube preamp questions
Post by: rnolan on February 15, 2014, 10:59:03 PM
Oh, but when has that ever been a problem?  >:D >:D >:D :metal:
  1  :thumb-up:
I found the STRs nice and tight with very clear tone and very nice controlable feedback so definitely worth a try.  But there are lots of tubes to pick from.  Doug said the STRs are JJs but a friend who's been to the Boogie valve checking thingy said they source tubes from all sorts of places.  My personal preference is the New Sensor Mullard reissues, much more 3D than the STRs and great in my MP2.
Title: Re: Soho Acoustics Qtr-1 tube preamp questions
Post by: ampguru on March 18, 2015, 02:49:47 PM
Hi Quattro Users,

i tuned for a long time my SOHO QTR-1 Quattro Clone, and got the best Results in Hot and Lead with 2 major type of Mod´s
Change the 3 Grid Leak Resistors from 1meg to 470kohm, and changing Values of the coupling Caps.

( while reinstalling the Original use of Lead, without the second Half Use of The Stage , look at the Schematik, it´s easy to realize, on the PCB it was already Prepared )

1meg Grid Leak was way to much, changing takes away the Mud and you get a much more Stabel Tone, without loosing Overtones.

Also there was a 1meg Bass Pot, wich muds anything to Shit, changed it to the desired Value of 250K.



Play it with ADA GCS-2 ( Cab Sim ) with Intellifex Mixed in Wet Only via a Mackie Mixer and i´m in Heaven.

No Problem with differnt PA or Monitor Systems anymore, Now Sounds great over any type of Soundsystem.
Simply Great

V1 Raytheon 12ax7 V2 Siemens ECC83 V3 und V4 Brimar ECC83

The Cathode Bypass Reduce Switching i took out Complete, The Thin Character i took away with clipping out the 220pico Bypass ( see the schematik ) and better Crunch i got this way also.

Put a Choke in, and Good F+T Elektrolytics, etc.....

Dead Silent now, even in Hot Channel via Headphone !!!!!!

Jibbi Du
Title: Re: Soho Acoustics Qtr-1 tube preamp questions
Post by: rnolan on March 19, 2015, 01:43:00 AM
Hey ampguru, good post, thanks  :thumb-up:
Title: Re: Soho Acoustics Qtr-1 tube preamp questions
Post by: kawai2g4b on March 20, 2015, 12:49:35 AM
Right on, I would have never expected that post anywhere, and major thanks!!  I'm going to look into those mods soon.