Yamaha E1005 - Weird Potentiometer tapers

[box_maker_1]

So, I posted this in the wrong forum - putting in the right place now.

I got my hands on a Yamaha E1005 analog delay that spent most of its life in a cloud of cigarette smoke. The pots are beyond salvage, so going to replace them first. Because nothing is easy, half the pots are common and the other half are not. I'd like the forum's thoughts on replacements.

Service Manual with Schematic is here: Yamaha E1005 Service Manual

Common tapers:

• Input A & B: A25K # Easy
• Feedback: B10K. # Easy
• Mod Speed: C250K # Uncommon but not too strange
• Mod Depth: B10K # Easy

Weird Tapers:

• Wet/Dry: D/B 10K. # This one has me stumped. It's a balance control so I'm thinking linear. But the "D" makes me think it has some curve. Think I could get away with a. B10K?
• Delay Time: ZD 5K # Super Stumped on this one - Internet sleuthing says a "D" pot is log but with slightly different curve. But I don't know about the the "Z" - Any ideas?

Cheers!!

 

[box_maker_1]

ok - so upon closer inspection of both the schematic and actual unit, I've solved half of the mystery.

"B / D 10K" Pot - is a dual gang affair with B and D tapers on separate wipers.

Still puzzling over the ZD 5K Pot - found a that post seems to indicate that a Z pot is just another term for a log pot, but seems odd that the devices has separately labeled A pots and the pot that is in the unit in fact labeled "ZD5K" so apparently this is a thing? Here is the Z pots = A pots post: Potentiometer FAQ

 

[box_maker_1]

Further internet sleuthing seems to indicate there is no such thing as a dual-gang pot with linear and log tapers. In fact, it would appear that for Wet/Dry controls the thing to use a "MN" tapered pot.

The MN taper means that at the center position both signals will be at 100%.

Likely the "B/D" pot in this device is actually an MN pot anyhow.

Google-fu has failed on the ZDF pot though, I will probably just order a linear and log 5K pot and try my luck.