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Quantec QRS/XL Reverb & Virtual machine success. Reverb/Delay Processors (HW)
Old 29th December 2009
Deleted 37a7726
Quantec QRS/XL Reverb & Virtual machine success.

Exciting day for my Quantec QRS/XL.
This classic verb unit was in need of an older PC host for full control. Not anymore. I've successfully created a working 1.6mb VirtualBox image that runs the 1987 software wonderfully on my Win 7 based DAW.
VirtualBox is mac, win, & linux friendly as well.
Attached Thumbnails
Quantec QRS/XL Reverb & Virtual machine success.-qrs.jpg  
Old 29th December 2009
Lives for gear
Casey's Avatar

Wow! nice job.

Tell us more. This sounds like an interesting story.

Old 29th December 2009
Lives for gear

Wow, that's very impressive. I have serviced a few XL's and have run them all successfully with a friend's old Sony laptop but this is much better. Details, please!
Old 29th December 2009
Deleted 37a7726
I've had this quantec laying around my bench. I feelt guilty every time I looked at that it wasn't getting used. Without the control software you can only use the factory presets. But the last thing anyone wants is another computer making noise in your control room.
The QRS/XL is controlled via a serial rs-232 port. The control software was written in 1986, it can be a bit picky with what hosts it will run on.
So I had the idea of trying to create a "virtual machine" to run the editor. So I did.
Virtual Box is a great open source virtual environment. I created a basic dos based VM from a floppy bootdisk image with the QRS software. It worked out great. Allows you to run it on your current DAW host.
This is the VM if anyone has an interest.QRS.rar

Here is a little history of the QRS XL from the quantec site.


At the convention »Tonmeistertagung« in Munich, Germany, November '86 - a new multi effect device with a revolutionary operator control is introduced to the professional community. The QRS/XL is no more configured and controlled by front panel dials and buttons like before but from various, effect-dependent display masks on a PC.
What was it the flattering editor of an inside magazine once wrote in his editorial: »If you want to see the future of effect devices, check out QUANTEC«.
Well, it didn't turn out quite as successful as we'd hoped. In those days, the first commercial attempts were being made to teach a PC things like multitasking. Actually, it was more of a procedure for a manual task switch. They didn't call it »Windows 87« but »Topview« or »Caroussel«. But: the whole mechanism simply didn't quite work yet. If a process was sent to the background, it would just sit there...
Oh, well. During the following months, our sophisticated clientel made it clear to us that for yet another PC, and just because of a stupid effect device, there was simply no room in a narrow sound studio. And that they weren't going to buy anything like that, sorry. Looking back, there actually were quite a lot of people who bought 'em. However, we did sell only half as many as of its famous predecessor. And half as many is just a flop in our line of business.

The signal processor, controlled by a 68008, was a small-scale integration, non-DSP. Using 32-bit instruction words, a complete MAC-sequence (Multiply/Accumulate) could be processed at an 8MHz clock rate - with all relevant memory access. In present-day counting, you could certainly compare it to an 8Mips/48Mops-RISC-machine. In any case, it wasn't until 10 years later, in 1996, with the introduction of the DSP56009, that the chip and memory technology were ready to provide a DSP performance, roughly equivalent to that of the XL, on a chip level.
We have already talked about digital interfaces. But a truly digital studio or at least a digital mixer were still science fiction in those days. So the QRS/XL was - still in quite contemporary style - equipped with built-in AD/DA converters which, as you can see in the photograph, took up a good 1/3 of the entire PC-board.
O.K., in those days, we only had 16-bit resolution, just like everybody else. But with the A/D, we did have a 2x, and with the D/A, 4x oversampling. And we already had a 32-bit signal processor, whose output signal was reduced to 16-bit, using dither. During a visit in Munich, our American importer in those days was flabbergasted when the developer showed him transmission behavior at -80dB. That's digital in there? Because of our famous »bypass program« the simple 1kHz sine test signals at the output looked exactly the same as at the input. All this without any dead zones or other strange behavior...
If our XL also would have had AES/EBU-interfaces back then - QUANTEC certainly would have made history in the field as one of the converter pioneers. You see, the ADs and DAs in the XL were simply terrific...
Old 25th January 2010
Deleted 37a7726
I've been getting some PM's asking how to connect the QRS to modern serial-less computers.
You will need a USB to Serial adapter + 9pin dsub to 25 pin dsub serial adapter.

Something like these.

usb to serial adapter - Google Product Search

Belkin PRO Series Serial cable - (DB-9) - F - (DB-25) - M - 6 ft - PC
Attached Thumbnails
Quantec QRS/XL Reverb & Virtual machine success.-base_media.jpg   Quantec QRS/XL Reverb & Virtual machine success.-base_mdia.jpg  
Old 13th December 2010
Gear Head

I just got this to work on OS X the other day and it's brilliant. Thanks for the idea and the help!


Originally Posted by rhythminmind View Post
I've been getting some PM's asking how to connect the QRS to modern serial-less computers.
You will need a USB to Serial adapter + 9pin dsub to 25 pin dsub serial adapter.

Something like these.

usb to serial adapter - Google Product Search

Belkin PRO Series Serial cable - (DB-9) - F - (DB-25) - M - 6 ft - PC
Old 12th April 2011
Here for the gear

OS 10.6.x and QRS/XL

Today I finally managed to connect my Mac to the QRS/XL. I'll post my configuration, maybe this is useful to someone:

Mac Pro with OS 10.6.4 running (open source) VirtualBox from Oracle. There I created a DOS Partition where XL.EXE is running (Disk-Image see post above or download it at Tools : QUANTEC Audio Pro)

Most important was getting the USB-Serial Adapter to work in OS X. I first tried some no-name brands, finally the Keyspan (now Tripplite) USA-HS19. That was the ONLY ONE working in 10.6.x. Of course you need a 9-Pin to 25-Pin Adapter to connect to the QRS/XL as well.

After having installed the driver (available at tripplite as well), you have to look up the correct name of the new serial port. I did it with Terminal by entering "ls /dev/tty*" which gives you the labels of all ports on the mac. The Keyspan Adapter was called something like /dev/tty.KeySerial1. I had to enter this name in the VirtualBox Settings of the DOS-Machine (see attachment), - that was it.

Hope this helps.

Attached Thumbnails
Quantec QRS/XL Reverb & Virtual machine success.-bildschirmfoto-2011-04-12-um-18.53.13.png  
Old 29th July 2011
Gear Head

installing DOS on VirtualBox???


I'm trying to get this working using VirtualBox VM on Mac OS 10.6. I had a little trouble sourcing DOS install media. I tried FreeDOS, but now it seems like it's taking me in circles and just keeps wanting to install itself everytime I launch the virtual machine. Would someone who's done this mind walking me through correctly installing DOS on VirtualBox, and then walk me through how to install the QRS software? I have the suggested hardware here, I just can't seem to get DOS going correctly. Maybe someone has the correct VirtualBox compatible DOS images?
I was 2 years old when this software came out and I'm not familiar with DOS at all.
Thanks for your help!
Old 11th May 2015
Here for the gear


We struggled for the last couple years off and on to get our QRS XLs working. I dug up this thread, walked through some of the stuff here, went off the map on some other stuff. Thought it may be helpful to someone down the road to have a roadmap for getting access to the software on a PC, since the instructions above are for Mac.

First, downloaded virtualbox and installed. Created a new machine of "DOS" type and found some DOS 6.22 floppy images on the web that I used to install DOS. You have to "insert" the first install floppy, then boot the machine and run the installer, swapping the floppy image to the second then third disk when you are prompted to do so. When the install completes, eject the image and reboot and you should see a DOS prompt.

I'd also suggest that at this early stage you download the generic DOS CD-ROM driver if you go the DOS 6.22 route, and install that. It should be a floppy image, so "insert" it into the virtual floppy drive in DOS and then run the installer. Next time you boot, you should be able to access virtual CD images (ISOs).

Next, had to wrangle the software from the host (Windows) into the guest (DOS inside the virtual machine). This was trickier than I thought. I ended up creating an ISO with the program IMGBurn that had the XL_200_d files from the quantec site linked above. Copied off the CD to the hard drive on a new folder. Ran the "install.exe" command and it installed the

There was some moment during install where it asks for the disk to be inserted into the A drive. I believe I copied the contents of the zip file above to a floppy image (IMG) in IMGBurn, and install proceeded smoothly.

The last hiccup was getting the USB-Serial adapter to work properly. DOS/ Windows name their serial ports just "COM1", "COM2", etc. I checked what COM port the USB adapter was claiming by going into device manager and looking at the device-- mine was set to COM1. So I set the guest port to COM1, mode to host-device, and host port/ path to COM1. You can set the guest port (the drop down menu) to whatever port you want, but the host port needs to be what port the computer claims for the USB adapter.

The communication is and was a bit glitchy, but after a few "reconnects" it worked. Issuing parameter changes takes a few seconds, but again, it works. Better than living with the presets.

Also, I setup a FreeDOS machine, and while there was much less struggling with copying files because drivers are all loaded, tab-completion exists, etc., the program didn't display properly. Maybe I could have set something in the machine preferences to make it work, but the DOS machine worked without diving in there.

Good luck, QRS-XL users.
Old 8th August 2017
Here for the gear

Hello everybody..

sadly the QRS.rar Download link is Offline..
Anyone could upload it again?

thanks in advance!
Old 9th August 2017
Deleted 37a7726
Originally Posted by Noobsaibot View Post
Hello everybody..

sadly the QRS.rar Download link is Offline..
Anyone could upload it again?

thanks in advance!
I just ported over the post/files.. QRS Software control VIA Virtual machine.
Old 16th August 2017
Here for the gear

thank u rhythminmind

i succesfully can run the software now..
also connected the quantec qrs/xl with a usb-9pin serial and 9pin-25pin serial.. (maybe i need a specific usb to serial adapter?)

but there is no connection between the quantec/xl and the software. (also routet the port in the qrs-software to Com1 as same on the pc)

is there something else i have to do?

thanks in advance
Old 18th August 2017
Gear Nut
rtype909's Avatar

i just got one of these, faulty and after replacement of a clock crystal, one bad cap and a bad vie on a densely populated board -- its working.

does anyone have a manual? my serial is 042 and i am on firmware 1.06 -- i assume this an early version

i'm going to make up a serial cable today and test the unit from a computer
Old 24th August 2017
Gear Nut
rtype909's Avatar
I'm looking for firmware of at least 2.00, the update is as below. The main thing is the lowpass cut (hi-freq).

Software update 2.00

Software version 2.00 include some enhancements and new features:

- Binary-Download
If your XL has EPROMS with the version number 2.01 or higher,
the software will use a binary format for the program download
instead of the Intelhex format.
This shortens down the transmit time by a factor of more than two.
Saving files in Intelhex and transmitting these files is not affected
by this changes.

- Octave Equalizer
The menue MISC-FUNCION now contains the item 'Octave EQ'. This
equalizer has nine frequency bands for each channel, Each band
can be set to levels between -20 dB and +20 dB. Because the equalizing
is done with FIR filters, the equalizer is completely PHASELINEAR
over the whole frequency range. This causes a 90 milliseconds group
delay, which must be taken into consideration, when mixing with
unprocessed signals.
If you save the parameters, using the functions in the FILES menu,
files with the extension '.eqf' will be created.

- FIR Compiler upspeed
The performance of the FIR compiler has been improved, especially
when changing frequencies or the filtertype. The very first compile
may still take some time, but all changes after that will
happen much faster. This upspeed makes experimenting with the
FIR compiler much more convinient.

- Initial Highcut in QRS Compiler
For a better approximation of the original QUANTEC QRS sound,
an additional lowpass is introdiced in the QRS compiler. This lowpass
effects the output of the simulated room, but not the additional
reflection. The lowpass can be selected in five steps as follows:

0 = no lowpass
1 = 12 KHz lowpass
2 = 10 KHz lowpass
3 = 8 KHz lowpass
4 = 5 KHz lowpass

- Appending with Hexsave and Binsave
If the menu items FILES-UTILITIES-HEX/BINSAVE find an existing file
with the same name and you deny overwriting it, you are offered to
append your file to the existing file. These concatenated files can
be transmitted as usual with the FILES-UTILITIES-TRANSMIT command.
Old 6th November 2017
Lives for gear
massimo's Avatar

Hi all,

can anyone here help this computer-hating old fart?

I bought the adapter cables required as per earlier posts.
In simple, plain words, what do I need to do now to program the QRS-XL with my pc?

Thanks everyone
Best regards
Old 9th November 2017
Lives for gear
massimo's Avatar

Any Quantec head out there?

Thank you
Old 5th March 2018
Gear Nut
rtype909's Avatar

i'm still on the look out for firmware 2.0 - does your unit have a later firmware?

as for serial, you have to make sure the DIP switches on the back correspond with the speed of comms. use 9600, if you have firmware 2.0 you can go to 19,600 but 9600 is fine as a baud rate.

are you on windows? If you are on windows up to 7 is fine for running it without additional software - use win98 compatibility mode, right click on XL.exe and hit advance and set accordingly.

Windows 10 - it no longer works without further software and you need to use VM/DOS box etc. Getting the serial port ready, in the VM, is key.

OS9 - use virtual pc 5

OSX 10.1 - 10.5 - as above

OSX - beyond, the posts above deal with this

Someone should write new software for the QRS/XL by snooping the serial port with a serial monitor. I have it on my list of things to do.
Old 7th January 2019
Is there a possibility to use the QRS XL DOS software with Mojave and VBOX ?

I installed VBOX and Eric Beam's VM, but I have no idea how to run the DOS program from the VM and route the USB to RS232 adapter into the Quantec.
Can anyone help me ? I don't know anything about the software at all and would be happy about a step by step description.

thanks a lot.
Old 20th January 2019
Gear Nut
rtype909's Avatar
Yes. i use brainboxes usb to rs232 : 1 Port RS232 USB to Serial Adapter - US-101 - Brainboxes - Industrial Ethernet IO and Serial have to assign the com port so Dosbox sends out serial data out of a 'real' port.
Old 21st January 2019
Gear Nut
rtype909's Avatar
**Safety Warning** Anyone with the QRS/XL ought to check the mains inlet filter 'disconnect first' - best is to simply replace it. I have had it fail in the Quantec and separately in a digidesign box - steam, venting and a really bad smell. it is a common failure even though this filter is rated for 1/2 Million hours.

see this post for details : HP 85685A: another mains filter failure – Schaffner FN 376 | SimonsDialogs

Mouser still have it stock and i hope Schaffner have used a better potting compound and replaced the paper capacitor. FN370-2-22 Schaffner | Mouser United Kingdom

Complete failure will exhibit as a unit that turns on intermittently. The fuse will not go, repeat the fuse will not go.
other symptoms, spikes in the audio - because the inlet filter is not suppressing voltage spikes

Last edited by rtype909; 21st January 2019 at 04:03 PM.. Reason: minor
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