Pioneer QX-9900 (Quadrophonius Gigantus)

Here are some pictures of a monster quad receiver

When I got it I tried tearing it down to give it a good cleaning and checkover, but got spooked when I saw the complexity. I don't want to be responsible for the death of an otherwise well-functioning receiver like this! I do love the "doghouse" shielding over the various circuit boards and whatnot under the top cover. The exposed board at the rear is the tuner board.

Fun stuff!

Nice looking unit! Pioneer wasn't known particularly for their quad gear, but that's a beauty! :thmbsp:

As for cleaning, look for some way to get the faceplate off to access the control pots along the front. Clean them with DeOxit/ProLube. Also clean the connectors on the back (use mascara brushes and.or pipe cleaners to get the DeOxit inside the RCA jacks and to wipe them clean). Also clean any fuses (both the fuse and their holder clamps) that you can find. Otherwise, you don't have to disassemble anything complex; there isn't a lot of dust in it (judging from the pics) and the only possibly problematic area left is relays, which are probably okay. Clean everything else and you should be fine. If not, you can always still take it to a tech who can handle the complexity and repair it.

Still, if you aren't used to cleaning gear that way, maybe practice on a simpler piece or two to gain confidence.

Actually, every quad unit I've seen, regardless of brand, is packed like that inside. It comes from trying to fit the extra decoders and channel amps into a near-normal-sized case. If you look at it for a while, though, you'll find that it is still well-organized and not that complex, just crowded. It's like having two stereo amps in one, but each basic amp is the same as any regular one (plus the decoding and routing stuff).

That is a good looking receiver. Thanks for sharing the great looking photos.

WOW! I have never seen that one before! Absolutely beautiful, and remember, being in the doghouse is bad. :nono:

Arkay said:

As for cleaning, look for some way to get the faceplate off to access the control pots along the front. Clean them with DeOxit/ProLube. Also clean the connectors on the back (use mascara brushes and.or pipe cleaners to get the DeOxit inside the RCA jacks and to wipe them clean). Also clean any fuses (both the fuse and their holder clamps) that you can find. Otherwise, you don't have to disassemble anything complex; there isn't a lot of dust in it (judging from the pics) and the only possibly problematic area left is relays, which are probably okay. Clean everything else and you should be fine. If not, you can always still take it to a tech who can handle the complexity and repair it.

Click to expand...

Actually, I got lucky. In the store where I found it, channels were cutting out. But working the pre/main switch on the back gave me all four channels nice and strong. And, none of the controls were scratchy, at least not after working them back an forth several times.

What spooked me most about a total teardown was the tuner dial string. I would have had to de-string the tuner to access the interior circuit boards. My previous experience with dial strings was

So, I thought...:nono:

The reverb control is pretty funky; you can get some pretty nasty "cavernous" sounds with it. With headphones, it becomes even weirder. Kinda like

For some reason it has a very nautical look to it,I don't know why. Maybe one of my gramps croonies had something styled like that on his boat. Q, What is that small black switch on the right in the next to the last photo do?

Craig

ya know, this should be 4chan's new logo. If you don't know what 4chan is, well, then, never mind, it's a internet thing.

stuwee said:

Q, What is that small black switch on the right in the next to the last photo do?

Click to expand...

That's the de-emphasis selector switch (75uS/25uS).

Awesome looking unit. I have never seen one of those, and I have seen a lot of Pioneer gear from that era.

It does look a little daunting on the inside. I would love to have one of those just for the asthetic impact.

I always liked the blue backlit tuners.

It does look nautical - it actually looks like a boat.

Or that limo from Sgt Peppers.

It's beutiful!

Nice. Some kind of Quad is on my Grab at the Right Time List.

Great fotos. Thanx
I love nudies.

Great looking receiver! I'm not familiar with that model at all, but it sure is nice looking gear. Both Pioneer and Marantz's four channel gear always struck a chord with me. I really like them!

I bit the quadraphonic (remember that term?) bullet hard at the very beginning (in '71 or '72) and bought a Pioneer QL-600A rear channel unit to add to my 1 year old Pioneer SX-626 receiver to build a four channel system. I also traded in my Pacific Stereo Quadaflex 2-way speakers on four brand spanking new Pioneer CS-R500 speakers. But I have to tell you that as a system it was very, very disappointing. And for a twenty year old college student who tied up a significant portion of his net worth in his hifi, it was really aggravating too! What was ironic about the whole thing is that individually the components performed very well, but never came together as a system. I still have that gear too!

I still use the CS-R500s regularly and have two installed in my garage/shop driven by the QL-600A and a Yamaha T-960II tuner. The other two CS-R500s are currently out of the rotation, but until recently, I had been driving them with my McIntosh MC-30 tube amps. Now THAT is a good combination! The CS-R500s and the MC-30s really bring out the best in each other. Up until about a month ago, I was using the SX-626 as a preamp in my second system until I replaced it with a Kenwood Basic C2 preamp that I scored off ebay.

Sometime in the near future, I am planning on installing the other CS-R500s in my garage/shop, so I'll have a quadraphonic configuration and then see if I can find a cherry quadraphonic receiver or two to play with. I might even give the SX-626 and QL-600A a whirl again, once I get them freshened up on the bench. Of course they might still be a big disappointment, but then again maybe not. It'll be fun to find out! :yes: I've also got a cherry Yamaha DSP-1 stored that I bought some years ago for $75 that I want to fire up again!