Alembic Guitars Club
Connecting => Miscellaneous => Topic started by: Crashnrobin on August 10, 2020, 07:51:49 AM
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Trying to figure out if this is real or a knock-off of some sort? Has some sort of ground issue. Any help is sincerely appreciated. It was in a closed out shop with a bunch of Korean-era electrics. Thanks in advance, Jim
(https://i.imgur.com/FDl4PZ6.jpg)
(https://i.imgur.com/rHLkUu5.jpg)
(https://i.imgur.com/SLr54Y6.jpg)
(https://i.imgur.com/hoQjhsL.jpg)
(https://i.imgur.com/xDfPhX8.jpg)
(https://i.imgur.com/XIPOYYK.jpg)
(https://i.imgur.com/YplkSJF.jpg)
(https://i.imgur.com/JN0wuWb.jpg)
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Looks like a Fernandes FAG 170 to me
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Shore Nuff! Interesting guitar. How does it sound?
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Thanks for the input. I really appreciate it. A Fernandes copy makes total sense, as all the guts appear to be Japanese. I don't remember this Fernandes copy at all...lol. It feels like it would be a great player with it's weight and nice neck. But it has a TON of hum and pickup output is week. Some of the switch positions don't work. It appears that a lot of people take the guts out and replace with more standard pickups and electronics.
https://yamauchi63133.wixsite.com/hikidaore/fag170-e
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Hi Jim, and welcome to the club. I agree that it’s a Fernandes. Nice score! A couple of things:
The bridge saddles (not the bridge) appear to be installed in reverse.
Also, the pickups are mounted incorrectly. Of the four mounting screws on each pickup, two should be UNDERNEATH the pickup. You should remove all four screws, then pull the pickup out of the cavity. With the pickup out, replace two screws, catacorner to each other and screw them down a bit. Then, place the pickup ON TOP of the two screws. Next put the two remaining screws through the other two catacorner holes of the pickup. You adjust the two screws whose heads are below the pickup to the desired height, then tighten the two screws whose heads are above the pickup to lock it down. So, when properly mounted, you should only see two screws on each pickup, mounted catacorner to each other, and two catacorner holes on each pickup.
Congrats on the new guitar.
Bill, the guitar one
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Thanks, Bill. That makes some sense with the pickup screws, as they were all thru the top and the pickups were WAY below the strings. A friend also told me to try a stereo cable, as this may also be a source of the hum. We shall see!
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Wow. So weird to see a low-end attempted copy of an Alembic. Makes you appreciate the fine details of the real deal!
How on Earth were the bridge saddles put on backwards? Since the threads are only on one side of each saddle, you need to disassemble the whole bridge, turn the entire thing around, put the saddles in the correct order, then insert the screws from the bottom side (same direction they are in now) so you have access to them for adjusting. But you'll still need to cut new slots because the spacing of the lower strings will be wrong. Wow, that's an amazing assembly error.
See how it plays with no amp, check for dead spots up and down the neck, see how it feels and sustains. If you like it then for the electronics side you could go many ways, from super simple to full-on Alembic kit. Not sure I'd trust any of the original components to work reliably. You gotta figure they cut corners on every single piece from the pots and switches to no pickup connectors at all - just soldered right in...
Good project axe!
Jimmy J
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Here's a catalog pic:
(https://live.staticflickr.com/65535/49047070141_c4b5a5482f_o.jpg)
Got this pic from a cool site with old Japanese catalogs (https://brochures.yokochou.com/en_index.html).
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Ground issue or bad adjusted hum cancelling dummy PU? You may look for directions on how setup hum cancelling system at Must Read section.
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Here is a pic from my files of another one showing the electronics. Hey, if you want to sell it, I am looking for another project!
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Well it showed up on my front porch today!
Thanks to Jim for selling it to me! It will make a great project as I delve into the electronics and get it all sorted out!
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Congrats, David! Looking forward to following the project.
Bill, tgo
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Well, it takes the same amount of time to clean one...
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Really nice work! Will you attempt to set the bridge saddles (not the bridge) the correct way?
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Friends of Fernandes probably know better than me but...
The original photos do look like the saddles are backwards.
The clean shiny photo makes it look like that IS their intended design.??. ???
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Yes, the saddle is not cut to the same profile as an Alembic saddle and is set correctly. There are various other subtle and not so subtle changes as well. BTW, I can tell anyone that wants to know that an Alembic 5 pin cable and power supply do work with these instruments.
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[BTW, I can tell anyone that wants to know that an Alembic 5 pin cable and power supply do work with these instruments.]
hope ya didn't let the smoke outta something finding that out! 🤯
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18 volts is pretty low
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Nice one, Dave!
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18 volts is pretty low
actually, you'd be surprised what you can trash if you get this backwards across something that's delicate like a guitar pre-amp circuit. you're pretty much guaranteed to take out an op amp, some discreet transistor circuits might survive it, signal diodes probably not. just because you didn't let the smoke out doesn't mean you didn't kill it.
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That's true. It has what were just OK op amps for back in the day (RC4558P) but not for these days. Can anyone suggest a better drop in replacement that does not use a ton of power? I will be using this with a power supply though.
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David, I’d be curious to see what you come up with. I restored my first Fernandes with non-series Alembic guts, converting the hum canceller into a middle pickup ala Stratocaster. I have a couple more Masterhands that are projects-in-waiting, on which I will have to do something about the electronics.
Bill, tgo
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I am beginning to think the fernandes circuit is designed to run on 9 volts total from their power supply and not 18. I just measured the op amp inputs and with two 9 volt batteries I get 8.93 volts dc and with the Alembic power supply I get 19.6vdc. I do not know if this is how a the Alembic circuit works, but could measure one as well. Right now I am thinking that the excessive hum might be from a dead middle PUP or transistor or something in that part of the circuit, but I don't know. I am unsoldering the PUP leads next to measure the PUP output.
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disclaimer: I spent many years as an analog circuits engineer, but i've been out the mix for a while.
i pulled up the spec sheet for RC4558P and its recommended supply voltage is +/- 5V. its max is +/- 15V, so be careful if you're using a +/- 18v alembic supply. Its current consumption rises fairly significantly at supply voltages above 5V. I would trade performance over power consumption in this case. You can definitely tell when you've put a crappy (i.e. low quality) op-amp in a pre-amp circuit, so battery usage be damned IMHO.
interesting discussion about this subject here: https://www.diyaudio.com/forums/analog-line-level/135546-rc4558p-replacements.html
putting a bypass cap right across the supply pins at the op amp is an old trick, pretty effective if you keep your leads short and use a good quality low ESR cap. It doesn't take much, maybe a 0.1 uF. ya gotta have a good hand with a soldering iron, because you gotta tack the cap leads right to the IC pins. I don't recommend doing this unless you're experienced soldering delicate electronic components and have the right equipment to do it, because you *will* cook the op amp if you can't get it done in under ~ 2 seconds. The intent behind this is to decouple power supply noise from the op amp and to prevent oscillation due to a high impedance power supply path. it doesn't take too much softness in the supply path to wreak havoc on the output, especially if there are rapidly changing signals with high frequency components.
i had to replace one one the op amps in my series II years ago, i don't remember what it was other than a dual op amp in an 8-pin DIP. You might poke around and see what alembic is using in their circuits, i'm pretty sure they've done their homework on these.
if you have access to a scope (i'm thinking this is a lost art these days. i work in an electrical shop and i can't think of anybody i know who knows how to drive one anymore except for me. when i draw a waveform on a piece of paper to illustrate a point, people's eyes glaze over... but i digress), it's pretty easy to trace out a hum. a good first step might be to get the op amp power situation straightened out and then go from there. if there's something funky going on there, you can spend endless hours chasing your tail trying to find it in the signal path.
good luck and happy hunting.
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Your middle pickup isn't a pickup. It is a "dummy" hum canceller - essentially wound wire with no magnet in the middle. It is part of the Alembic-designed hum-cancelling system.
Bill, tgo
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David, please read this before messing with your guitar's hum cancelling system.
http://club.alembic.com/index.php?topic=269.0 (http://club.alembic.com/index.php?topic=269.0)
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Thanks for the help. First thing I tried when I got the guitar was the hum canceling procedure, but it would not eliminate a fairly loud consistent hum.
Right now for fun I am installing IC 8 pin sockets on the board so I can swap in and out the op amps. I found 3 of the same op amp chips on an old Peavy amp circuit board I keep around for parts.
Eventually after figuring out the hum I want to try swapping some better newer chips in there.
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Can any electronics experts help me with any knowledge about the transistors this thing uses? There are 4 marked K66 P .99 and 2 marked K66 R 88
I think they might be vintage Panasonic FETs but that is about all I can find.
Thanks,
Dave
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did you ever get any enlightenment on this? if not, i was gonna do a quick lookabout to see what i could find out. i did a lot of discreet transistor design work back in the days of my youth, so i may be able to shed some light on it. maybe.
just so that i don't reinvent the wheel, what searching have you already done?
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I have just searched the web and found some info that makes me think they are vintage Panasonic FETs. I also have an old vintage Shin-E Four in the Floor drum stomp box (MIJ) that uses transistors with the same logo marking, which makes me think they are vintage Japan made parts. I would love to find an equivalent that I can swap in so I can test the originals. Right now I have finished soldering in the chip sockets and swapped in some identical op amp chips to test them (works the same).