Roland RE-201 Space Echo Heads

I was looking to buy a local Space Echo to fix and flip, but I didn’t because the erase head looked like this:

 

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Notice the line going down the middle of the erase head.

That line going down the middle of the erase head gave me cold feet, because if I learned anything from tape machines is that heads wear and eventually open up and the gap between the poles shows, and presumably that is what I was seeing here. So I started looking online for examples of RE-201 erase heads. Here’s what I found:

So as you can see, most heads have a line. The Echo shown in pictures 4 and 5 don’t have a line down the erase head, but these are also a bit blurry, so maybe I’m just not seeing it. So maybe all these are examples of heads that started to go, or maybe that’s just the design? I emailed the folks at soundgas.com to ask for their opinion. If you’re not familiar with them, they refurbish and sell a lot of different tape echoes, so I figured they would know. And they did. Here is their response:

A very thin vertical line should be there – it’s the dividing line between the two poles of the head. However you shouldn’t be able to feel it – if you can then the head is not right.

So indeed this is the line between the two poles, but IT IS normal for it to show. And there’s even a little method of testing it. I’m still a bit unsure about this being the design of the heads, but at the same time, the unit I was looking at was erasing, and probably so are all the other examples I found online.

Photo credits: First (Soundgas LTD), second (stuffandfood.wordpress.com), third (StudioRepair.com), fourth and fifth (stickylight.wordpress.com). I only download and re-upped these photos in case those sites ever go down.

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Grounding and Rane Note 110

I made a cable to connect my Kilpatrick PHENOL, which has unbalanced outs, to my recording interface (MOTU 16A) which has balanced inputs and outputs.

I’ve read Rane’s note #110 about interfacing unbalanced lines with balanced a few times and thought that I’ve internalized it well at this point. I followed no. 14 on their diagram and made a TS to TRS cable, but when I plugged the cables in I got a pretty nasty 60Hz hum at -60dB. At the same time TS-TS cables work fine and their noise floor is at -110dB!

The PHENOL is using a wall-wart and is therefore un-earthed and floating. This means that its enclosure (and therefore its audio ground) is one big antenna. Feeding that antenna to the balanced line’s “-” injected all that noise into the inputs of the interface. According to a friend, Rane note #110 is only applicable when both devices are earthed, and that makes sense.

 

I got an HP 6205B bench power supply from eBay, so I can start breadboarding stuff. The left side’s output was constantly at 40V and didn’t respond to the pots. The service manual is pretty thorough and has a little section about what to do when that happens, and one of the suggestions is to check if A6 to A8 is open (or some other two connections with A prefix). These are two of the terminals on the back and there was no jumper between them. I jumped them and the left side was working. Ordering a jumper for it.

Then I cleaned the enclosure because it was really sticky. The panels that were easily removed I took to the bathroom and washed them in the tub with dishwashing soap and a toothbrush. The front panel and knobs I cleaned carefully with hot water, dishwashing soap, and q-tips. I also discovered that the bottom pots (for adjusting the voltage) are missing the toothed washer and nut. At the hardware store these measured 3/8″-24 (meaning the fit over a 3/8″-24 rod but loosely). In reality, they’re 3/8″-32. Ordering a few nuts and washers right now. Getting a few extra because they fit other pots and 1/4″ jacks, so they’ll be good to have around.