What’s on *YOUR* workbench?

[Cybercow]

Picked up this Kay 703C amp from a yard sale for twenty bucks. It's in nice cosmetic shape, except for the mouse nest stuffed inside the chassis. Cleaning it out revealed the intact original circuit. I'm planning to recap and install an isolation transformer later this fall.

That is a rather spiffy find. Good on ya.

As an old fart, I remember the Kay 703 being known as a "widowmaker" - because of its transformer not being isolates. (Or something deadly like that. I've slept since then.)

Even tho you're getting an isolated x-former for it, for safety's sake, please sniff around real good at the AC input, transformer(s), chassis and large caps.

 

[keevohn]

That is a rather spiffy find. Good on ya.

As an old fart, I remember the Kay 703 being known as a "widowmaker" - because of its transformer not being isolates. (Or something deadly like that. I've slept since then.)

Even tho you're getting an isolated x-former for it, for safety's sake, please sniff around real good at the AC input, transformer(s), chassis and large caps.

Yep, thanks for the head's up. There's a fair amount of info out there for making these amps safe to play. The isolation transformer and a 3-prong cord with proper grounding seems to be the ticket.

I was tempted to plug it in as-is just to see how it sounded, but the previous resident chewed through the 2-prong cord. It's probably for the best

 

[Fama]

Moonn Space is Fun (Reverberation Machine) with the feedback mod and a BTDR-3H instead of the 2H, where I put a Decay pot on the extra pins so I can control the Decay. Sounds fun, right?

Well it was a huge fucking pain in the ass soldering all the pins because the brick doesn't fit where it should because of the extra pot, and the extra pot works in the wrong direction, plus the feedback doesn't work very well if the decay is not set to the longest possible. Plus the bright side is almost unuseable, but from what I've read that's... pretty much just how it is.

I also burned a TLC274 because I put it in the wrong way around, so this currently has a TL084.

Buuuut with all of that, it's pretty fun at what it does. Colors the dry signal very heavily, it's much bassier (I think a TL074 might help a bit with that, I'll try to see if Tayda has them in stock for my next order or maybe LCSC). It's not a "add reverb" pedal, it's a "ok today we will use the Reverberation Machine and see what else might work with it" pedal. But that's also fine, at least it's something different. I've got a Gravitation reverb waiting for a "normal" reverb build.

Tried new knobs too, or I don't know if I intended them for this one or something else, but at least they look nice.

 

[Harry Klippton]

Moonn Space is Fun (Reverberation Machine) with the feedback mod and a BTDR-3H instead of the 2H, where I put a Decay pot on the extra pins so I can control the Decay. Sounds fun, right?

Well it was a huge fucking pain in the ass soldering all the pins because the brick doesn't fit where it should because of the extra pot, and the extra pot works in the wrong direction, plus the feedback doesn't work very well if the decay is not set to the longest possible. Plus the bright side is almost unuseable, but from what I've read that's... pretty much just how it is.

I also burned a TLC274 because I put it in the wrong way around, so this currently has a TL084.

Buuuut with all of that, it's pretty fun at what it does. Colors the dry signal very heavily, it's much bassier (I think a TL074 might help a bit with that, I'll try to see if Tayda has them in stock for my next order or maybe LCSC). It's not a "add reverb" pedal, it's a "ok today we will use the Reverberation Machine and see what else might work with it" pedal. But that's also fine, at least it's something different. I've got a Gravitation reverb waiting for a "normal" reverb build.

Tried new knobs too, or I don't know if I intended them for this one or something else, but at least they look nice.

View attachment 55735View attachment 55736

Some folks make elaborate cardboard mockups in cases like this to check fitment before finalizing the enclosure to avoid exactly this problem

 

[Guardians of the analog]

the extra pot works in the wrong direction, plus the feedback doesn't work very well if the decay is not set to the longest possible. Plus the bright side is almost unuseable, but from what I've read that's... pretty much just how it is.

This is why even after 300 builds I still always rock before I box. Pot working in the wrong direction just needs to have legs 1 and 3 swapped. It's easier to test things out of the box and audition values and make changes before you commit and box it up.

 

[Fama]

Some folks make elaborate cardboard mockups in cases like this to check fitment before finalizing the enclosure to avoid exactly this problem

I get my enclosures pre-drilled from Tayda so it wouldn't be that helpful for me, although maybe in this case I could have soldered some of the caps on the "wrong" side of the board and the brick could have then maybe fit (also on the "wrong" side, conventionally).

Or just use the older Belton brick and leave out that one pot. But in this case I already had the extra version 3 brick.

 

[benny_profane]

I get my enclosures pre-drilled from Tayda so it wouldn't be that helpful for me, although maybe in this case I could have soldered some of the caps on the "wrong" side of the board and the brick could have then maybe fit (also on the "wrong" side, conventionally).

Or just use the older Belton brick and leave out that one pot. But in this case I already had the extra version 3 brick.

In this case, you would verify the drills before submitting the order.

 

[Paradox916]

I get my enclosures pre-drilled from Tayda so it wouldn't be that helpful for me, although maybe in this case I could have soldered some of the caps on the "wrong" side of the board and the brick could have then maybe fit (also on the "wrong" side, conventionally).

Or just use the older Belton brick and leave out that one pot. But in this case I already had the extra version 3 brick.

You can also do mock-ups in a vector program, you just need a scale to know how big the parts are and figure out clearances , sure it’s tedious but it’s almost a necessity when doing a lot of complex mods on a single build, patience really pays off with this sort of thing. Next time give it a try and if it’s still not for you at least you gave it a try and now you know, but I will put money on you will like the end result.

 

[Bricksnbeatles]

Finally found the terminal blocks I had for Protoboard #2
This one features a mega chunky switch, just for fun (feat. Messy workbench in the background— trying to redo my entire parts organization method)

 

[Paradox916]

Finally found the terminal blocks I had for Protoboard #2
This one features a mega chunky switch, just for fun (feat. Messy workbench in the background— trying to redo my entire parts organization method)
View attachment 55743

What 3v regulator did you use?

 

[Bricksnbeatles]

What 3v regulator did you use?

The one from the BOM. Fig sent them to me way back when I got my first Protoboard, and there was an extra of both of them. Since I later wound up with another Protoboard, I just used the 3v3 and 5v spares on that, so I never wound up needing to source an alternative. I think there was a build report from someone who found an available alternative

 

[Paradox916]

The one from the BOM. Fig sent them to me way back when I got my first Protoboard, and there was an extra of both of them. Since I later wound up with another Protoboard, I just used the 3v3 and 5v spares on that, so I never wound up needing to source an alternative. I think there was a build report from someone who found an available alternative

This was something I totally forgot about until I pulled mine out the other day and couldn’t remember why I didn’t have a 3.3v reg. Lol.

 

[steviejr92]

This was something I totally forgot about until I pulled mine out the other day and couldn’t remember why I didn’t have a 3.3v reg. Lol.

I’m running mine without one as well. Lol I don’t think there’s anyone here that has a 3.3v reg. I remember those being hard to source.

 

[Paradox916]

I’m running mine without one as well. Lol I don’t think there’s anyone here that has a 3.3v reg. I remember those being hard to source.

I do remember thinking “ I’ll deal with that later” and completely went down a different rabbit hole

 

[KR Sound]

Speaking of finding non-functional pedals on Reverb, I did pick this up for $40. It was only made in 2008b but the 30ga-looking wiring inside was all broken, and the enclosure is in great shape minus one small area that I’ll try to repair. I’m going to rewire this, replace the footswitch, and add a power jack to it. I think I’ll also build a small board with polarity and power protection for it if I don’t just do it inline.

 

[steviejr92]

I do remember thinking “ I’ll deal with that later” and completely went down a different rabbit hole

This is exactly what happened to me!

 

[Locrian99]

Well after picking this up this morning with a completely broken off bright switch decided to open it up. Temporary fix while I try to find a replacement switch. So far no kick. It’s a slide switch but would be nice to find the exact type. It’s a 1983.






Hopefully I can manage to find a replacement cove chorus switch but that one was at least working. It sounded great before fixing the bright switch. The chorus switch I e never seen anything like it before it’s like got a lot of lugs! Lol.

 

[lrgaraujo]

Today I tried UV-curing soldering mask for the first time. I had limited success (enough for the board to work, I think). I'll report again during the week

 

[KR Sound]

Well after picking this up this morning with a completely broken off bright switch decided to open it up. Temporary fix while I try to find a replacement switch. So far no kick. It’s a slide switch but would be nice to find the exact type. It’s a 1983. View attachment 55754View attachment 55755View attachment 55756View attachment 55761View attachment 55762

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Hopefully I can manage to find a replacement cove chorus switch but that one was at least working. It sounded great before fixing the bright switch. The chorus switch I e never seen anything like it before it’s like got a lot of lugs! Lol.

Here’s what someone did to tame that bright switch a bit:

Bright Switch on Roland Jazz Chorus

I just bought a used JC-50, a pretty nice amp for solid state. I checked in several places and couldn't find too much information on this older model, so I figured a few things out myself that I thought I would share.First is the bright switch, for which although there were numerous complaints ab...

www.harmonycentral.com

 

[Phil hodson]

Well after picking this up this morning with a completely broken off bright switch decided to open it up. Temporary fix while I try to find a replacement switch. So far no kick. It’s a slide switch but would be nice to find the exact type. It’s a 1983. View attachment 55754View attachment 55755View attachment 55756View attachment 55761View attachment 55762

View attachment 55761

View attachment 55758

View attachment 55763
Hopefully I can manage to find a replacement cove chorus switch but that one was at least working. It sounded great before fixing the bright switch. The chorus switch I e never seen anything like it before it’s like got a lot of lugs! Lol.

Nice amp! I’m still on the look out for a 50. Have seen a 55 locally so might give that a try.
Love the 120 sound but don’t need the noise or the weight!!!