A Qrx-9001 and a 4140

Jollie610

New Member
Hello all, first post on the forum and was unsure of where to put it. I have recently aquired a Qrx-9001 for from what I've gathered perusing eBay, is a decent price. I'm wondering if I have any options of using my Marantz 4140 amp and the Qrx together in any possible way or if they would be better suited as entirely separate entities.

Thanks!
 
Best as separate units, unless you really prefer the sound of the 4140's amplifier. I'll not delve into the Sansui versus Marantz debate (both are excellent makes, each has their die hard fans), but the 9001 lacks pre-out/main in facilities so taking a preamp signal out to feed a different amplifier will require modification to add such connections.

The quad decoding and synth capabilities of the 9001 are exceptional, while most of what I've read on the subject (to be clear, I've not listened to any Marantz quad hardware myself) has indicated the Marantz quad decoders are underwhelming in terms of how good a 4 channel effect they produce.

All that said, any 9001 in unrestored condition will almost assuredly not be up to par. It has one particular problem with bad solder joints for vias (pass through joints) on a key circuit board and all of these need to be redone for proper passage of signal on all four channels. This is just the most glaring issue that will need attention, the driver stage needs minor corrections due to age related failure of several components, the quad decoder stage will need a proper alignment.

Further, given these are 40 years old now, they should receive a full re-capping. Much has been written here over years now on what needs to be done, the search facility will bear out many threads on the 9001 and related models, and what work should be done and how to go about it for the DIY'er, though I'd not recommend taking the job on as a first effort. It is a very complex unit and access to some parts is difficult without lots of disassembly.
 
Best as separate units, unless you really prefer the sound of the 4140's amplifier. I'll not delve into the Sansui versus Marantz debate (both are excellent makes, each has their die hard fans), but the 9001 lacks pre-out/main in facilities so taking a preamp signal out to feed a different amplifier will require modification to add such connections.

The quad decoding and synth capabilities of the 9001 are exceptional, while most of what I've read on the subject (to be clear, I've not listened to any Marantz quad hardware myself) has indicated the Marantz quad decoders are underwhelming in terms of how good a 4 channel effect they produce.

All that said, any 9001 in unrestored condition will almost assuredly not be up to par. It has one particular problem with bad solder joints for vias (pass through joints) on a key circuit board and all of these need to be redone for proper passage of signal on all four channels. This is just the most glaring issue that will need attention, the driver stage needs minor corrections due to age related failure of several components, the quad decoder stage will need a proper alignment.

Further, given these are 40 years old now, they should receive a full re-capping. Much has been written here over years now on what needs to be done, the search facility will bear out many threads on the 9001 and related models, and what work should be done and how to go about it for the DIY'er, though I'd not recommend taking the job on as a first effort. It is a very complex unit and access to some parts is difficult without lots of disassembly.
Excellent advice. :thumbsup:
 
No pre-amp out on the QRX, but the QRX has the superior decoding, so I would just restore the QRX and stick with that.
 
When I receive the unit I'll test all functionality and maybe post some pictures. This would be a first for me and from what I've looked at, as well as sansuiman's comment, it's not something to be taken lightly. I guess I will have to start a small saving fund for the restoration of this monster.

Quite bummed about not being able to use both of them without modifications to the qrx. But I could always find some other uses for the 4140 (Home Theater is what I'm thinking) if I'm going to use the QRX as my main stereo in the long run.

Unsure about link rules but heres the unit I bid on while slightly inebriated at the bar: https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/283261167057
 
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Just came in this morning and holy huge! Unpacked it and fired it up. Connected to NLAdvent & Marantz HD660 up front and a set of Bose bookshelf's in the back. All four channels come in with no dropping (yet). Tested all settings for quad (other than CD4) and they all work. Didn't touch the Dolby knob or try power x2 since all I've read on that seems to be to stay away from it. All in all it seems to be functioning quite well (FM , Phono, Aux, Tape). It may not be in tip top fully restored shape but as it stands everything is in working order. Now to find something sturdy enough to hold it up lmao.
 
Just came in this morning and holy huge! Unpacked it and fired it up. Connected to NLAdvent & Marantz HD660 up front and a set of Bose bookshelf's in the back. All four channels come in with no dropping (yet). Tested all settings for quad (other than CD4) and they all work. Didn't touch the Dolby knob or try power x2 since all I've read on that seems to be to stay away from it. All in all it seems to be functioning quite well (FM , Phono, Aux, Tape). It may not be in tip top fully restored shape but as it stands everything is in working order. Now to find something sturdy enough to hold it up lmao.
You are very lucky, I have a customers QRX9001 on the bench now, and its not a happy unit.
I'm in for a long journey with this one I can see....
This one i have is very tidy cosmetically, it just doesn't work so well...most of the lamps are blown too...
 
Yeah, cosmetically this one has it's problems. The veneer is cracked on the back of the left panel, small ding in the metal vent, aluminum is a little dingy could use a good cleaning and polishing. Also, the LR Balance knob is bent quite a bit. Haven't looked at the knob without the dial on to see the extent of the damage but it's pretty messed up.

Either way I'm going to start saving up for the inevitable failures so I can send it out for restoration at a later date.

Definitely a 10/10 drunk purchase so far.
 
QRX 9001 is a fun project for the beginner when it comes to restoration ...

stage-two-teardown.jpg


pile-of-caps.jpg


(... or not, depending on if you're a masochist.) <G>

Mine spent most of a year on the bench here, but I wasn't in any hurry and wanted to make sure I got it right the first time. ** Doing it again if I had problems didn't seem like something I'd much like to do ... I'd rather slam my (insert body part here) in a drawer and slam that repeatedly).

That said, it IS the TOTL of quad, and there's no going back.

** I was lucky enough to score a nice little QRX-6001 as a backup while the big un was on the bench.

Oh. The dreaded pass through problem has already been mentioned. You might be lucky, but probably not as it's a common issue with these. Try cycling the mode buttons and see if you get any dropouts - that's a sure sign. If you can get a good four channels on SQ, that's my favorite for most anything anyway, including a majority of my regular stereo sources.
 
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