hmmm...remember kustom amps?

[wavley]

I don't see a boost feature in PC1000 circuit.  

...

Wavley, if you know the board numbers of the boards I can dig up my archives to see if I have corresponding schematics.

Yours has likely two preamp boards.... one - probably the aforementioned PC1000 - with VOL, TREB, BASS, SPEED, INT, TREM-VIB and REV knobs in it. All for one channel. And another preamp board for another, much simpler, preamp channel with just BASS, TREBLE and VOL knobs.

K100 will have a 100W power amp board + regulator of the particular time period but all in all those didn't change much except for very first Kustom amps with very "vintage" design with interstage transformers and all. They got rid of that about right from the beginning and went forward with the simple RCA circuit, just upping the rail voltage and number of power transistors if higher power was demanded. I think they didn't change that strategy until they abandoned the tuck-n-roll styling alltogether.

I don't remember my board numbers, I think it's going to be a couple of weeks before I open mine up.  I'll let you know when I do.

The bottom right corner of the PC1000 schem says "Pre am w/boost, trem, vib." honestly I didn't really look further than that on this glance because I don't have boost, unless they mean the pull for bright switch, because now that I look at it, there is no boost actually in the schem.  I think it's been about two years since I had this thing open, so maybe it is PC1000.

[R.G.]

Near as I can tell, the "vib" on these amps is a single phase-shift stage with no summing, much like in the earlier Magnatone amps, but implemented differently. In fact, it's implemented three different ways on the three sets of schems shown here.

One is an LDR/lamp setup reminiscent of the Univibe, which I now believe was lifted from electric organ practice in the 60s. Another was a set of diodes set up as a variable resistance. This was common for some things back in the mid/late 60s, but suffers from very limited signal levels. Thomas Organ used this kind of modulator as a tremolo in their Vox amps, and it sounds GREAT for that, but suffers from noise from the low signal level. There's another example of similar use in the Steiner-Parker synth filter module. The third is the use of OTAs for modulation, those 80848's, similar to the phase stage of the Small Stone.

Fender got a similar effect by splitting highs from lows with a filter, then amplitude modulating the two separately and out-of-phase, and finally adding the two back together. There was some intense phase shifting in the crossover region. The Fender "Concert" amp did this, I believe. Magnatone used a pair of voltage-variable-resistors to implement something like the Univibe phase stage, but done with tubes.

An interesting question is then - are there noticeable advantages in one way versus the other? Is there virtue in replicating exactly the circuit or updating it and adapting to modern pedal practice, which is considerably more sophisticated today?

[Mark Hammer]

Or maybe the folks from Strymon and Line 6 simply need to score a couple of Kustom amps, and model the effect. 

[pinkjimiphoton]

Or maybe the folks from Strymon and Line 6 simply need to score a couple of Kustom amps, and model the effect. 

SACRILEGE!!!!!!

ideally, i would say go with whichever of the approaches would be easiest to implement.

it SOUNDS pretty much the same on every kustom. the classic plexi of the late 60's would get my vote, but i believe RG said that's the hardest one to do.

i know a lot of peeps would love the sound. i built a wobbletron (multiple, in fact) and never got it to work, but i built a bearfoot magnavibe, which is almost the same circuit, and it's close. REAL close. but it's vibe only, doesn't do the trem or the weird point where you can dial it between the two and get a subtly pitch changing tremolo.

btw...the "boost" is treble boost if i recall correctly.

been looking at the fuzz, too. (honestly, at this point, i look at every fuzz i come across, i probably have a couple thousand at least schematics i've accumulated) i never used a kustom with built in fuzz, but peeps seem to like them....and apparently some used a diode clipper pair, some a single diode (which i bet would sound really nice if it only worked on the top of the waveform).

again, this is all above my paygrade. i think the key may be to take something as simple as the wobbletron, which is based on the magnatone (and i'm sure ross was trying to capture) and see if maybe something can be done to make it sound right.

i'm more than willing to be a guinea pig if someone wants to throw a couple ideas out there and build them. i'm familiar with the sound of a few of the models (including the late stage "hybrids" of the end, with solid state pres and tube amps...they sound like poo!!)

i guess screw the vintage parts. we need something to be a "work alike/sound alike" that can fit in a box.

john fogarty i'm sure would be ecstatic.

[Mark Hammer]

I'll put in a plug here for the "phase-filter" sound.  If you have not done it, you owe it to yourself to try it.  Seriously.  If you trusted me on the harmnic Percolator thing, this deserves equal attention.

I mention it here because it sounds best when there is no clean signal mixed in with it.  Two stages of all-pass (phase-shift), followed by 2 stages of lowpass, harnessed to the same LFO, delivers up a swampy combinaton of vibrato, auto-wah, and a surplus tremolo sound produced by the apparent shift in loudness from when you rob and restore the top end.

If you have an OTA-based phaser, whether a Ross, a Small Stone (and issue), or a DOD FX-20, each phase-shift stage will have a small value capacitor tied to the input of the stage.  Rerouting that cap from the input to ground will convert it from all-pass to lowpass.

[wavley]

but it's vibe only, doesn't do the trem or the weird point where you can dial it between the two and get a subtly pitch changing tremolo.

i guess screw the vintage parts. we need something to be a "work alike/sound alike" that can fit in a box.

john fogarty i'm sure would be ecstatic.

This.

[pinkjimiphoton]

I'll put in a plug here for the "phase-filter" sound.  If you have not done it, you owe it to yourself to try it.  Seriously.  If you trusted me on the harmnic Percolator thing, this deserves equal attention.

I mention it here because it sounds best when there is no clean signal mixed in with it.  Two stages of all-pass (phase-shift), followed by 2 stages of lowpass, harnessed to the same LFO, delivers up a swampy combinaton of vibrato, auto-wah, and a surplus tremolo sound produced by the apparent shift in loudness from when you rob and restore the top end.

If you have an OTA-based phaser, whether a Ross, a Small Stone (and issue), or a DOD FX-20, each phase-shift stage will have a small value capacitor tied to the input of the stage.  Rerouting that cap from the input to ground will convert it from all-pass to lowpass.

i've only got two phasers, the korg mister multi and a cheap behringer small stone knock off...but it's smt, and i'm not quite ready to kill it yet.

is there a particular box you reccomend mark? something i can build fairly easily? the closest thing i've messed with to a phaser is the wobbletron/magnavibe. it's not the same as
the kustom sound, but close.

lately live, i've been using an old boss be5 with a plug stuffed in the "b" output jack...that way it nukes the dry signal from the chorus in it, and gets a bloody delightful wobble to it.
the wobbletron used to live on my board, but it was really prone to noise issues from the power supply, and battery life is minimal cuz the led is always running in it.

ideally, i'm hoping RG can come up with a work alike/sound alike.  i will trust him on this one...and i trust you on this too.

i don't wanna mess with the korg, but maybe i can find a vero of a nice easy phaser i can mess with.

[Mark Hammer]

The Ross/Ropez is probably the best DIY candidate for this.  I would say "Have a go at the Behringer Stone clone", but yeah, the SMT part would make it somewhat tricky.  

[R.G.]

The Ross/Ropez is probably the best DIY candidate for this.  I would say "Have a go at the Behringer Stone clone", but yeah, the SMT part would make it somewhat tricky.  

One of the things I marked down to snag the first time it came along was a B&L stereo zoom microscope. It took over 15 years, but I did get one surplus for $100. Soldering SMD parts by hand is entirely practical under this puppy, under the lowest possible magnification.

But, like single malts, B&L stereo zooms are an acquired taste.

[pinkjimiphoton]

thanks mark.
that's a great idea, RG... but still not ready yet to take the SMD plunge.

i've seen charlie's mod.... may be something to look into, but to me, the kustom has it beat... there's something to be said for toneful simplicity.
all too often, i've modded something, and then modded more...and more... it's a disease (BUTM) 

but the thing is, yah, you can get a million sounds, but how many are you gonna actually use? i'm learning more and more often, that less is more.

jmo... i believe unless it's gonna be really useful, it's not worth messing with.

[wavley]

The Ross/Ropez is probably the best DIY candidate for this.  I would say "Have a go at the Behringer Stone clone", but yeah, the SMT part would make it somewhat tricky.  

One of the things I marked down to snag the first time it came along was a B&L stereo zoom microscope. It took over 15 years, but I did get one surplus for $100. Soldering SMD parts by hand is entirely practical under this puppy, under the lowest possible magnification.

But, like single malts, B&L stereo zooms are an acquired taste.

I work under an Olympus SZ11 all day long, we have the B&L stuff here, but I much prefer the Olympus because I just can't seem to get used to the B&L ones.  Of course I would just love to have either one at home because I have no intention of doing epoxied chip and wire stuff at home and I think that the B&L scopes probably really shine with the SMD components with the larger work area/distance.  And also, I don't think you can touch the Olympus used for less than $1200.  I think I'm going to have to get a little more active about finding a home microscope because more and more I'm finding that they make life so much easier.

[Mark Hammer]

The Ross/Ropez is probably the best DIY candidate for this.  I would say "Have a go at the Behringer Stone clone", but yeah, the SMT part would make it somewhat tricky.  

One of the things I marked down to snag the first time it came along was a B&L stereo zoom microscope. It took over 15 years, but I did get one surplus for $100. Soldering SMD parts by hand is entirely practical under this puppy, under the lowest possible magnification.

But, like single malts, B&L stereo zooms are an acquired taste.

Last summer, I repaired a Variax, and posted about it here.  During the "repair" (actually, cleaning up an "installation" that a buddy did with a soldering iron that was really meant for plumbing repairs), a teeny-tiny resistor was sweated to movability, and in the jostling, fell onto the bench-top.  These things are the size of a small sesame seed, and at first we thought we had lost it on the garage floor ( ).  Eventually we found it, and I was able to re-install it, narrowly averting tragedy.

But the real point of THIS post is that, at least when it comes to SMT resistors, those little suckers can be magnetically attracted, and because they are so small and light, it takes practically nothing to attract them.  I tried holding it down with my wife's old dissection tweezers from biology class, sweating the piece, and then pulling tweezers and soldering iron away...but the damn resistor clung to the tweezers.  Eventually, I had the bright idea to hold the resistor in place with a toothpick, and that did the trick.

As G.I. Joe says: Knowing is half the battle.  But simply being able to see better is not the entire other half.  Getting the damn parts to stay put without following anything  around that has the teensiest bit of magnetic charge to it is about 10%. 

[R.G.]

But the real point of THIS post is that, at least when it comes to SMT resistors, those little suckers can be magnetically attracted, and because they are so small and light, it takes practically nothing to attract them.  I tried holding it down with my wife's old dissection tweezers from biology class, sweating the piece, and then pulling tweezers and soldering iron away...but the damn resistor clung to the tweezers.  Eventually, I had the bright idea to hold the resistor in place with a toothpick, and that did the trick.

As G.I. Joe says: Knowing is half the battle.  But simply being able to see better is not the entire other half.  Getting the damn parts to stay put without following anything  around that has the teensiest bit of magnetic charge to it is about 10%. 

I like to use a Q-tip to wash the pads area in liquid flux, then let it dry a bit until it becomes tacky. Then I use a small probe with a bit of tacky flux on the tip to both pick up and align the parts. Once they're in place, I hold the part down with the probe, and touch the soldering iron to one pad under the part and reflow the solder on the pad, which reflows the solder on the part end. Once one end/pad is soldered, however partially, the other end/pads can be reflowed without holding the part down any more.

Once all parts are soldered, isopropyl alcohol and a toothbrush removes the flux. Using flux residue as a temporary adhesive seems to be just about right, for me at least.

I keep my old Weller 150W soldering gun specifically for demagnetizing tools as needed. Haven't soldered with it for years.

[wavley]

But the real point of THIS post is that, at least when it comes to SMT resistors, those little suckers can be magnetically attracted, and because they are so small and light, it takes practically nothing to attract them.  I tried holding it down with my wife's old dissection tweezers from biology class, sweating the piece, and then pulling tweezers and soldering iron away...but the damn resistor clung to the tweezers.  Eventually, I had the bright idea to hold the resistor in place with a toothpick, and that did the trick.

As G.I. Joe says: Knowing is half the battle.  But simply being able to see better is not the entire other half.  Getting the damn parts to stay put without following anything  around that has the teensiest bit of magnetic charge to it is about 10%. 

I like to use a Q-tip to wash the pads area in liquid flux, then let it dry a bit until it becomes tacky. Then I use a small probe with a bit of tacky flux on the tip to both pick up and align the parts. Once they're in place, I hold the part down with the probe, and touch the soldering iron to one pad under the part and reflow the solder on the pad, which reflows the solder on the part end. Once one end/pad is soldered, however partially, the other end/pads can be reflowed without holding the part down any more.

Once all parts are soldered, isopropyl alcohol and a toothbrush removes the flux. Using flux residue as a temporary adhesive seems to be just about right, for me at least.

I keep my old Weller 150W soldering gun specifically for demagnetizing tools as needed. Haven't soldered with it for years.

This is pretty much what I do.  I also have multitudes of expensive tweezers, pin vices, and instead of toothpicks I use wooden cotton swabs that I have cut off the cotton part and sharpened to various shapes for the different parts (I like this over toothpicks because they are longer and easier to keep steady in my hand).  A good number of the parts I use at work are less than 10 mils square, unpackaged transistors and such.  Often times some of the parts I use are so small and are being placed in channels that tweezers won't fit in that I have to use a wooden stick dipped in alcohol and the surface tension is enough to pick up the part and place it.

[stallik]

I work under an Olympus SZ11 all day long, we have the B&L stuff here, but I much prefer the Olympus because I just can't seem to get used to the B&L ones.  Of course I would just love to have either one at home because I have no intention of doing epoxied chip and wire stuff at home and I think that the B&L scopes probably really shine with the SMD components with the larger work area/distance.  And also, I don't think you can touch the Olympus used for less than $1200.  I think I'm going to have to get a little more active about finding a home microscope because more and more I'm finding that they make life so much easier.

15 years ago I picked up a Russian dissecting scope in a junk store for £10.  I've used it regularly and now find it essential for soldering dirty great components as my eyes start to fail. I can see SMD components well with it but to solder them, I'd have to get round the the shaky hands which, at that magnification makes the tip of my soldering iron look like I'm trying to cast a spell - even when I brace my hand against something

[R.G.]

This is pretty much what I do.  I also have multitudes of expensive tweezers, pin vices, and instead of toothpicks I use wooden cotton swabs that I have cut off the cotton part and sharpened to various shapes for the different parts (I like this over toothpicks because they are longer and easier to keep steady in my hand).  A good number of the parts I use at work are less than 10 mils square, unpackaged transistors and such.  Often times some of the parts I use are so small and are being placed in channels that tweezers won't fit in that I have to use a wooden stick dipped in alcohol and the surface tension is enough to pick up the part and place it.

Occasionally when I go to an oriental restaurant with free/disposable chopsticks, I grab a pair for the work bench. They're adapted to human-hand use for moving small objects for a few millenia. I keep a couple of these with a hole drilled in the business end and a sewing needle pressed into the hole eye-end-first and a wire soldered to the needle for a precision electrical probe. Much easier to get to SMD pads and leads and easier to keep stuck into the target pad/lead than the stock multimeter probes. Sounds like you need this kind of thing more than I do.

[wavley]

This is pretty much what I do.  I also have multitudes of expensive tweezers, pin vices, and instead of toothpicks I use wooden cotton swabs that I have cut off the cotton part and sharpened to various shapes for the different parts (I like this over toothpicks because they are longer and easier to keep steady in my hand).  A good number of the parts I use at work are less than 10 mils square, unpackaged transistors and such.  Often times some of the parts I use are so small and are being placed in channels that tweezers won't fit in that I have to use a wooden stick dipped in alcohol and the surface tension is enough to pick up the part and place it.

Occasionally when I go to an oriental restaurant with free/disposable chopsticks, I grab a pair for the work bench. They're adapted to human-hand use for moving small objects for a few millenia. I keep a couple of these with a hole drilled in the business end and a sewing needle pressed into the hole eye-end-first and a wire soldered to the needle for a precision electrical probe. Much easier to get to SMD pads and leads and easier to keep stuck into the target pad/lead than the stock multimeter probes. Sounds like you need this kind of thing more than I do.

I actually have the precision Fluke probes and often times they're still too big.  I use a pin vice with a sewing needle in it that I soldered a mini banana jack in the open end and then insulated with shrink wrap, that way my regular multimeter probe will fit in the end.  We end up having to improvise a lot of tools here, it's really hard to find tweezers with small enough tips so I use an old ceramic MUX to sharpen them.  I should also give credit to the wonderful precision machine shop downstairs that is constantly building me chassis, fixtures, and modifying tools for me, especially now that I've moved from cryogenic amp production (even production is small scale, the four of us in my old group produced about 100 amps a year total and even that was hard to meet) to advanced receiver R&D.

When the frequencies get into the GHz, things start getting interesting... and small.

[wavley]

I work under an Olympus SZ11 all day long, we have the B&L stuff here, but I much prefer the Olympus because I just can't seem to get used to the B&L ones.  Of course I would just love to have either one at home because I have no intention of doing epoxied chip and wire stuff at home and I think that the B&L scopes probably really shine with the SMD components with the larger work area/distance.  And also, I don't think you can touch the Olympus used for less than $1200.  I think I'm going to have to get a little more active about finding a home microscope because more and more I'm finding that they make life so much easier.

15 years ago I picked up a Russian dissecting scope in a junk store for £10.  I've used it regularly and now find it essential for soldering dirty great components as my eyes start to fail. I can see SMD components well with it but to solder them, I'd have to get round the the shaky hands which, at that magnification makes the tip of my soldering iron look like I'm trying to cast a spell - even when I brace my hand against something

I find that I have to keep the perfect balance of caffeine in my system, not enough and I can't pay proper attention to detail, too much and it looks like an earthquake under the scope.

[pinkjimiphoton]

so...any progress or ideas yet on how to implement one of these puppies?

i'm still finishing off a new overdrive/fuzz i cobbled together. to ME it's new, and uses some different ideas..
to you guys it'll probably be a piece of this, a piece of that. hope to have it up soon. just adding a couple snubber caps to kill a little hiss, and stupid pedal trick arriving..

[Mark Hammer]

I find that I have to keep the perfect balance of caffeine in my system, not enough and I can't pay proper attention to detail, too much and it looks like an earthquake under the scope.

I think it also helps to be a tiny Indonesian lady with very small hands and slender fingers...or an industrial robot.