Latest Rat Tweaks - Minimal But Effective!

[11 Gauge]

Okay, so we all seem to have Rat fever around here (sure beats the swine flu, heh )....

Just like with the DS-1, I think I've come up with some VERY minimal mods that should give a boatload of mileage to the average user. I hope they aren't subjective tweaks, but I have a feeling that they aren't, as they attempt to keep the stock Rat nature properly underpinned, just "refined."

Step 1 - Decrease the compensation cap to 7pF. No other value. Trust me. Just do it. You can thank me later. (Okay, that's a bit overboard - methinks I'm sleep deprived).

Step 2 - Alter the 2.2uF/47 ohm HP filter pairing to 1uF/100 ohms. It helps if you decrease the 560 ohm resistor tied to the 4.7uF cap to 470 ohms, but it's just icing on the cake...

...That's it, folks! Dropping the comp cap allows the thing to breathe and sizzle A LOT better, IMO. Fantastic for cleanup at lower drive settings especially. Altering the upper mid HP filtering to "half the gain" keeps the necessary mids that the Ruetz mod kills off, but balances them much better against the bass HP filtering. And neither of these mods kills the stock Rat vibe one iota. If anything, it makes the pedal much more flexible for other tweaks. LED clippers like in the Turbo Rat now sound so much nicer, IMO. Heck, just about any clippers seem to sound better.

I'll try to get a sound clip up in the next few days, but don't hold your breath. Too much going on. Do yourself a favor and tweak these 3 or 4 components for yourself, and tell me what you think...

[Higgs F. Boson]

Thanks!

[JohnnyCrash]

I'm still giving myself migraines trying to draw up a workable layout on perfboard for my upcoming Rat build...

I drilled the enclosure and mounted the pots/hardware, I've sorted the parts, now for the hard part

[11 Gauge]

Originally Posted by JohnnyCrash

giving myself migraines trying to draw up a workable layout on perfboard

Perf can be a real b_tch for op amp designs. It's a little easier with sockets, but the pins are still just a tad too short, IMO. I like to be able to bend the pins over in the perf. This is assuming that it isn't pad-per-hole, in which case you better have a steady hand and a clean tip!

I REALLY like perf for transistor builds, though. I could build them all day long and enjoy it. Maybe a SuperDuperHandofGod Muff with 12 transistors cascaded, 8 Vex SHO's in a row (basically two Box of Rock), etc.

I've seen people use perf FOR IC's for their op amp builds. Paul C. used to use it in his Timmys until recently. I just don't like jumpering or cutting tracks. The Rat has a few "extra" parts compared to other op amp gainers - the comp cap, the small bleeder to ground on the input, the jFET output buffer. It gets crowded fast.

...But if Landgraff can build his M'od (a verbatim Rat using "top shelf" components) on a tiny chunk of perf using Mal 150's and carbon comps, it can be done. Of course, he sockets everything, and doesn't bother to secure them down with hot glue or similar. But what do you expect for roughly half a grand?

[yonie]

I would really like a sound clip on this. Maybe if the result is convincing enough i might have a go at some soldering myself. I'd first have to find out what a compensation cap is, though.

If you are to create a sound clip please include settings where overdrive is only slightly enabled with volume and tone all the way up and one where overdrive is set to noon with tone at 9 o'clock and volume at 3 o'clock.

Thanks!

[JohnnyCrash]

Originally Posted by 11 Gauge

Perf can be a real b_tch for op amp designs. It's a little easier with sockets, but the pins are still just a tad too short, IMO. I like to be able to bend the pins over in the perf. This is assuming that it isn't pad-per-hole, in which case you better have a steady hand and a clean tip!

I REALLY like perf for transistor builds, though. I could build them all day long and enjoy it. Maybe a SuperDuperHandofGod Muff with 12 transistors cascaded, 8 Vex SHO's in a row (basically two Box of Rock), etc.

I've seen people use perf FOR IC's for their op amp builds. Paul C. used to use it in his Timmys until recently. I just don't like jumpering or cutting tracks. The Rat has a few "extra" parts compared to other op amp gainers - the comp cap, the small bleeder to ground on the input, the jFET output buffer. It gets crowded fast.

...But if Landgraff can build his M'od (a verbatim Rat using "top shelf" components) on a tiny chunk of perf using Mal 150's and carbon comps, it can be done. Of course, he sockets everything, and doesn't bother to secure them down with hot glue or similar. But what do you expect for roughly half a grand?

I socket all transistors and op-amps. I used perf on my recent Red Llama build...

I wish the pins were longer to bend too, but once I got one pin soldered down the thing stayed put enough for me to wokr with.

That Red Llama perf build was a pain for all sorts of reasons. I don't know why I only use perf, but I don't think I have too many more builds ahead of me anyway.

ibobunot posted a link to a perf Rat layout, but I don't have that exact type of perfboard. I have the RadioShack type with two long copper strips going down the middle... looks like a trip to the store before I can start building my Rat.

[11 Gauge]

Originally Posted by yonie

If you are to create a sound clip please include settings where overdrive is only slightly enabled with volume and tone all the way up and one where overdrive is set to noon with tone at 9 o'clock and volume at 3 o'clock.

Thanks!

Considering that unity gain occurs at around 10:30 at most settings, that is going to be SCARY loud. I'm about to fiddle around with it now, but doubt I will get to recording anything - already 3 pm here, with lots to do.

In the meantime, what kind of guitars/pickups/amps do you want to hear? I mean, obviously Teles, but I've also got a hardtail type Strat with a 'bucker only in the bridge (normal output), I've got a carved top Tune O Matic type Strat thing with a Duncan JB in the bridge and DiMarzio HS-3 in the neck...

...As for amps, I'd like to keep it to the lower wattage stuff, as I've been just killin' the neighbors lately. That means probably either a Vibrolux Reverb, a Deluxe Reverb, or a Blackheart Little Giant into a 1X12 cab...

I need to get some guitars set up for P90's and 'trons. Good thing that Santa is on his way.

[11 Gauge]

Originally Posted by JohnnyCrash

I wish the pins were longer to bend too, but once I got one pin soldered down the thing stayed put enough for me to wokr with.

Yeah - that's where an awesome pair of needle nose are a necessity. I love my red handle Crescents.

I just tack down the two staggered corners, and go from there.

I used to like pad-per-hole, but not any more. The plain stuff seems to not be as available as in years past. I might grab some vero from Futurlec eventually, but old habits die hard. I like to populate and start soldering inside of 5 minutes, usually much less. Too many projects to get done otherwise.

...I'm about to fire up a EA Trem build this weekend (big snow supposed to hit tomorrow). I'll be etching a board tonight just to expedite the process...

[tjk3052]

Originally Posted by 11 Gauge

Step 1 - Decrease the compensation cap to 7pF. No other value. Trust me. Just do it. You can thank me later. (Okay, that's a bit overboard - methinks I'm sleep deprived).

Step 2 - Alter the 2.2uF/47 ohm HP filter pairing to 1uF/100 ohms. It helps if you decrease the 560 ohm resistor tied to the 4.7uF cap to 470 ohms, but it's just icing on the cake...

Thanks for this. I have a BYOC rat kit on the way, I think I'll incorporate the HP filter change using a SPDT ON-OFF-ON switch to go from 'stock' to 'Reutz' to 'your' values. Will decrasing the compensation cap have any negative effect when using the other clipping methods included in the kit?

The RAT fever is spreading!

[11 Gauge]

Originally Posted by tjk3052

Will decrasing the compensation cap have any negative effect when using the other clipping methods included in the kit?

No - and I've actually confirmed this. I swapped diodes that drastically altered the clipping threshold in both directions, either more or less. I also tried all of the popular current methods, like 2N7000 mosFET's, with great success - the subtle difference of the "knee" that their body diodes limit at is more perceivable.

[tjk3052]

I finished my BYOC Rat today. Turned out great, and once I realized I hadn't put the chip in, sounds great too. I put an on-off-on switch between R4 (47 ohm) and R5 (560 ohm) to go from stock to Reutz mod to 11Ga's recommendation. The Reutz mod is not a subtle change, and I'm not sure if I like it yet, but the other 2 positions are great. I didn't have a small (7pF) cap for the comp cap so I'll have to change it later. The 6 way switch makes this thing have a ridiculous amount of settings, my fav so far are stock and turbo.