bixonic expandora

[pinkjimiphoton]

i got one apart on my bench right now, fixing it for local legend jimmy dubonet.

it was a BEAR to get apart. someone had "fixed" the footswitch by tightening the outside nut to the point it stripped and fused on, and they twisted it hard enough to actually destroy the switch inside. joy.

to get it out, only one way to fly. you gotta use a solder sucker and some wick, heat up each node of the totally cheap ass dano style input jacks and then separate the board from them.

they mount the jacks first, then solder the board to the jacks. kinda like an experience pedal, but thank god this doesn't have dual traces on it like the prescription electronics did.

i found the part for the switch at small bear, but ended up buying them from my boy lawrence at bitches love my switches as i could buy a couple of them shipped for what it would cost at small bear, and so thru a bunch of other loot in my sack.

it's an alpha 107-SF12011-L is the closest you can get. from what i understand researching here you have to bend the lugs to get it to fit, i was like... oh, joy.  lawrence has the knock offs that are a little closer than the alpha's which i also went for, anyways...

the switch is a short one, a standard stomp won't fit in there at all, and it is designed to solder right into the pcb. my FAVorite.

but i figure while i got it apart, if anybody needs pics or values or any of that crap, let me know and i will do my best to supply the info.
i've only seen one schem for it which is "purported" to be it, figure you don't see many of 'em so it's hard to come by a proper reference.

i will say this, at cursory glance last nite... it's gotta pair of lm308's and a jrc4558 in it...  a double rat into a toob screamer? lol
beats me.

but if anyone wants pics, i will try and get them for you. once this thing's parts come in, i won't be able to access them anymore, so....

[digi2t]

Nice write about it here, plus mods;

http://www.codtone.com/downloads/2246413/Codtone+Expandra+Build+Doc,+Notes+and+Mods.Rev+2.0.pdf

R.G. did a write up on it over at Geofex.

4 knob vero;

[pinkjimiphoton]

that looks wayyyyyyy easier to do than the one i got on the bench.

i was just curious, cuz the schem on the net is "purported" to be correct which makes me wonder if it's legit or a work alike.

i will check geo for it, it's been a while. thanks dino!

[Kipper4]

Thanks Jimi and Dino.
Saved to file.

[digi2t]

WOOOT!! I have some H11F1's at home. Might just give this a shot!! Have to dig up some LM308's though.

Jimi, take a break from the expandora and go eat some pineapple dude. It'll soothe your soul. 

[pinkjimiphoton]

lm308's ya can get at tayda. the bixonic one doesn't use the "mojo" can ones.
lm301's work almost identically in a rat circuit.

i'm a gonna go crank me up some pineapple express...
and get a couple photon faces done

[digi2t]

Good man!!

Got a line on some LM108's. Waiting on a shipping price. 

[pinkjimiphoton]

you mean lm308, or lm301?

not familiar with a 108

http://www.linear.com/docs/1704

hah, there is a 108!

here's the 301's i use

http://www.utm.edu/staff/leeb/LM301.pdf

[digi2t]

The 108 is the "heavy duty" version of the 308. It has a wider temperature operating range than the 308, and I think a higher voltage operating limit too.

[pinkjimiphoton]

nice. will the cork sniffers approve?

i like the old metal can chips. they just look cool. i dunno if they sound any better. i always test 'em out in different things, but hardly ever use 'em other than in rats.

[digi2t]

nice. will the cork sniffers approve?

Hah! Dunno. That one's going to keep me up tonight.


Not. 

[pinkjimiphoton]

 

[PRR]

> not familiar with a 108

Most of the "3xx" parts came in 1xx and 2xx grades.

108 is Military, should handle insane temperatures, may have tighter specs.

208 is Industrial, wide but not insane temp range.

308 is Commercial, a temperature range still wider than any you would play at.

Original prices could have been $50 for the 108, $5 for the 308. Obviously pedal-floggers have no need to pay big bucks more for temps they never want to see. So the world is (was) full of 308s.

Now that Military and Industrial demand for 108 is about zero, those old-stocks of 108 and 208 are being dumped for what they can fetch.

[digi2t]

HA HA!!! Look what I found!



Yes Comrade! Russian counterpart to LM108. Stick THAT in your toupee Mr. Trump! 

Need to go decipher the datasheet now..... never mind, picture is worth 1000 word;

http://xn----ctbgeuhdtdb2b.xn--p1ai/cfiles/market/4092/1480988363.pdf

Just need to figure out which are the inverting/non-inverting inputs. They use a little circle, I'm not familiar with that symbol.

EDIT: Praise Google translate! The little circle indicates the non-inverting (+) input.

The pinout is as follows;
1, 8                    Коррекция (Correction)
2                        Вход  инвертирующий (- input)
3                        Вход  неинвертирующий (+ input)
4                        Напряжение  питания  минус Ucc (- power)
5                        Свободный (No connection)
6                        Выход  (Output)                                         
7                        Напряжение  питания Ucc (+ power)

Same as the LM308.

[pinkjimiphoton]

lol... i'm just glad canadians still have our first amendment, we won't be using it for a couple years here at least 

[anotherjim]

The little circle is the same meaning as when used for "inverted" on logic gates. You usually see them on the output side, but they can equally be on the input as...

[digi2t]

lol... i'm just glad canadians still have our first amendment, we won't be using it for a couple years here at least 

The inherent vice of capitalism is the unequal sharing of blessings; the inherent virtue of socialism is the equal sharing of miseries.
~ Winston Churchill ~

[digi2t]

Putting together a JMK board right now. I've added the Bass/treble boost switches from the Codtone site. I also decided to use a pot for the drive, instead of the switches. I decided to use a footswitch to jump it into the "Forbidden" zone.

The drive pot that replaces the switches is a 1K linear. Now, the switches, notwithstanding the forbidden setting, give you three resistances; 560R, 1.1K, and about 371R with the two in parallel. Using a 1K pot, I used a 330R resistor between lugs 2 and 3, and a 110R resistor on lug 1. The other end of the 110R resistor goes to the board, as does lug 3 of the pot. Sweeping the pot gives you all the resistances of the switches, with all the in between settings too. As for the forbidden mode, the switch will break the connection between lug 3 and the board of the new pot. In a pinch, you could use a switched 1K pot as well, using the switch to go into forbidden mode. I would however use a resistor instead of going wide open in forbidden mode, which is totally unruly. Maybe I'll try a 1M trimmer to try and find a resistance that will be "out there", but useful.

As for the diodes, I've tried a bunch of different types, including germaniums, but the best sounding ones are some NOS 1S1588 Japanese diodes that I bought a while back. Looking at some Expandora gutshots, the seem to look identical, right down to the blue bands.

The LM108's are great. I haven't got the Russian ones yet, but I really like the LM's so I soldered them in. An old 4558DV is sitting in a socket. I might swap in something else to try, but the DV is working quite nicely. A 5087 is the transistor of choice here.

The H11F1 is what I'm using, and seems to work fine. I must say though, I had to check the units I bought from Ebay, 3 out of the batch of 10 that I bought were defective (no resistance swing with varying voltages applied, just dead).

My initial testing has my ears drooling. From what I've read, there's a bit of a love/hate relationship with this circuit, but I absolutely LOVE it. With the Drive knob set just so, and a setting the Gain pot to the amount of distortion desired, this is one absolutely interactive beast with the guitar volume. Backing off the volume, it cleans right up, and I mean "right up". Very clean. I can maybe push it a tad into grind if I really dig in, but not a peep of dirt if so desired. Dial up the volume, and grind galore comes to life. Quite frankly, I'm so impressed, I just bought a 2000R version on Ebay, and I'm looking forward to looking at the guts of that one. Wish I could find the 2001 version schematic. The links over at the other place are broken, but from the small picture, it looks really different from the other versions.

[Chugs]

Found this in my travels. I believe it is the 2001 version.

[Gus]

2206 datasheet note the resistors. That is why the codtone has two added ones by the 5087
http://pdf1.alldatasheet.com/datasheet-pdf/view/92220/TOSHIBA/RN2206.html


You can find this in the "Schematics" link at the top of the page. Wow I drew that back in 99 when I fixed one.