Sort of OT: blast from the past

[wogg]

A classic Rat Shack 10 band EQ with RTA. Dug up from storage, DeOx on the switches and put into service to correct old Yamaha media speakers a bit for the home office. I've had that EQ since I was a teenager, lots of good years of service.

[tomzarbo]

That a beautiful piece of equipment man, I remember it pretty well from back in the day. Good on you for saving some of that cool stuff, wish I had. That thing still looks good!

TomZ

[Wolf]

Sub looks about as old...
Wolf

[Geoff Millar]

Looks cool indeed: "Realistic" as a brand name sort of sounds a bit 'ACME' (as in the Roadrunner cartoons) but they made some nice, under-rated gear sold here through Tandy Electronics - long gone unfortunately.

Geoff

[Justtheone]

Love the EQ

Sub looks about as old...
Wolf
I first thought that was a strange place⁸ for a microwave.
Cheers

[tomzarbo]

Love the EQ

Sub looks about as old...
Wolf
I first thought that was a strange place⁸ for a microwave.
Cheers

I was thinking "Space Heater" myself, but I didn't look that closely.

[wogg]

LOL... yup, the sub is almost as old. The EQ is circa 1989 or so, the sub is part of a Yamaha YST-50 set circa 1997 and are getting a little yellow in the plastic. That's been a good set, the sub is excellent for it's size and I recon could compete with a Voxel down to 40Hz. The satellites are the weak spot, I used pink noise and RTA to fix them a little. Definitely not a critical listening spot.

[norman bates]

Slightly b4 i worked at rat shack.

does it have an expander button ?

[wogg]

Sure does, IMX Expander with an adjustment knob. Never liked that though.

[wogg]

Well, after using that sucker for a bit, I do have a problem. The L channel is down about 10-12dB for some reason. It's not connections, the balance is fine as soon as the EQ is bypassed. The sliders all work as expected and I attempted to compensate by shifting the pattern on the sliders up to balance it a bit. Not great though. Inside it's all discreet through hole parts, shouldn't be tough to repair but without a schematic to follow it'll be hard to follow the signal path to see where the gain drops.

This thing may go into the vintage equipment museum in the sky. Now I should just design a 2.1 setup for my home office and kick the old dull Yamaha setup as well, what a bummer

Edit: found a schematic, it's really fugly. All discrete BJT in the signal path with very minimal IC's. I'm going to need younger eyes to read this thing and trace the signal.

[Weber]

My best friend back in the day had that same EQ along with a pair of Realistic Mach 2's. It was an impressive sounding system for it's time.

[wogg]

I always drooled over those Mach 2's. Those tiny ports are hilarious for a 15" woofer knowing what I know now.

[tomzarbo]

Well, after using that sucker for a bit, I do have a problem. The L channel is down about 10-12dB for some reason. It's not connections, the balance is fine as soon as the EQ is bypassed. The sliders all work as expected and I attempted to compensate by shifting the pattern on the sliders up to balance it a bit. Not great though. Inside it's all discreet through hole parts, shouldn't be tough to repair but without a schematic to follow it'll be hard to follow the signal path to see where the gain drops.

This thing may go into the vintage equipment museum in the sky. Now I should just design a 2.1 setup for my home office and kick the old dull Yamaha setup as well, what a bummer

Edit: found a schematic, it's really fugly. All discrete BJT in the signal path with very minimal IC's. I'm going to need younger eyes to read this thing and trace the signal.

Hey Wogg,

I know you're experienced, and not to sound condescending, but did you hit all the pots, buttons and switches with the appropriate detoxit formula to see if there isn't some sort of oxidation or corrosion on one of more of the mechanical bits in the signal chain? I know this is obvious and you've probably already tried it... not to mention that 10db is a lot for an issue like this, but it's worth a shot if you haven't done it.

TomZ

[wogg]

Sure did Tom. There's no master level pot on the thing for either or both channels, so a across the spectrum gain drop is likely a component problem on the board. May just be a leaky old electrolytic.