Quad-Eight Mic Pres for trade

[haydenb]

I got a rack of eight QE 7510 cinema pres. Barrier strip in, barrier strip out. Fully discrete. Transformer in and out. There's some buzz in about half the modules. I'm going to tech through it this weekend. Working bipolor 24 volt powersupply.

Why don't I want them anymore? I got myself an old 1974 Yamaha PM-1000. Fully discrete. Transformer in and out, and I like it better. I need some other stuff. Mics...a compressor/limiter...I'll take a lot of really great broken stuff. I'm into the tech side of things. So if you have some old piece of gear you can't get rid of, let me know.

I'm not really interested in money for them...yet. I'd just end up blowing it on gear anyway, so I thought why not skip the middle man. Let me know if anyone's interested. I don't check the boards very often, so email me.

hayden@haydenmag.com

Hayden

EDIT: It was brought to my attention that I said transistor instead of transformer. It was late when I wrote this. My apologies. Pictures will be posted by the end of this weend, November 17th.

Thanks for looking.

[kylethompson]

I'm not really interested in money for them...yet. I'd just end up blowing it on gear anyway, so I thought why not skip the middle man. Let me know if anyone's interested. I don't check the boards very often, so email me.
Hayden

So you want to trade? What are you looking for? Anything specific?

[haydenb]

I didn't have anything specific in mind. I mean, there's no paticular model of anything I'm dying to have. I hear very good things about the FMR compressor. I hear the ashly sc50, while cheap used, does a good job. Studios always seem to have a couple dbx 160's. I could use some more work horse mics. Crown cm 700. Shure sm57. Beyer 201. Beyer ribbon anything.

I'm not looking for all of these things. But some combination. I rank importance of gear like this.

1) Well treated room.
2) Good mics
3) Good pres
4) Good post pre eq and compression
5) Decent A/D conversion.

So I'm shooting for 2 and 4, with the emphasis on the latter part of 4.

[jpschust]

you sure, cause ive got a great room you can use in southern indiana

[meblumen]

Although I'm not familiar with the cinema pres they peaked my intrest. Anyway, is there any chance you could give me a monetary value you think the pres are worth so I can take a look at my gear and see what, if anything I'm willing to part with that you might be interested in. Also, jpschust, where are you located, I'm in Bloomington, IN.

[jpschust]

im in bloomington too, i was jokin about the room, im working on building my rig right now- you a student at iu?

[Boz]

Hey;

I'm not familiar with these preamps but I'm interested in quiet and transparent pres.

I have a Leader LBO522 Oscillascope availble for trade, Dual trace, 20 mHz responce, 500 uVolts/div sensitivety.

I'm looking for high-quality pres for my Mackie MDR 2496 hard disk recorder.

Thx!

Boz

[haydenb]

I'd price the pres at around $50 a channel. Say $400 for the whole rack including power supply.

[haydenb]

Ok, so I spent a few hours with my tech friend today. We decided that these quad eight things aren't really mic pres, but they are preamps. But it seems, the way they look, is that they're repro cards for a tape machine. There's an eq module missing, and someone did some eq mods on the bottom of the board to replace that module. As a result, the bottom end drops out about 4dB around 100hz. Makes them sound a bit thin. However, the head room is good. We got about 50dB of gain or more without clipping.

But, we also found what we suspect to cause the buzzing. The preamp isn't putting out equal out of phase balanced signals. The signals are out of phase, which is good, but the amplitudes aren't equal. That makes the common mode rejection poor when running into another piece of equipment. I'm trying to get some schematics for these to work through it, but really at this point I just want to take them off my hands.

I imagine, the common mode problem could be easily solved if the output on the barrier strip was taken only as hot and a possibly floating shield. This would make the output unbalanced but, if the output lines were short, there would be less of a problem then the balanced output is giving right now.

All in all, I have no pictures, the QE's are still at my friend's house, and I just want to get them off my hands. They're old. They're not perfect. They're kind of strange, but I did use them for mics, and I did get some pretty sweet guitar sounds out of them. When cranked, they sound pretty electric.

Who wants them? Money or best offer.

Hayden

[Boz]

You've got me interested in the Quad-Eight amps now (oh boy another project... )

I'm not sure a problem with output waveform (positive/negative symetry) could cause hum.
The ouputs are probably push-pull, so maybe a problem with the phase inverter or a driver/output transistor for the bad half-cycle.
The hum may be a seperate problem.
I love a challenge.

I think you said they were in a rack with pwr supply.

I'd swap you my Leader dual-track o'scope even-up.

Email me at JeffBosley@webtv.net if you're interested.

Thx