Getting bad compression in a Rat dist.

[blanik]

hi, i made a Proco Rat dist.   it sounds awsome (exactly like i remembered the original), my problem is that when i hit the strings hard and quickly, the attack phase of my sound gets horribly clamped down, like some sort of bad compressor (i know compression is inherent in distortions but this one is bad!!) never had this on a dist. before
i've put a switch in my pedal to select between regular diodes (1N914) and LEDs and the problem seems worst with the LEDs... otherwise it would be perfect!!

since i used all the part values from the original Rat,

--is it possible that the original Proco issued Rat had this "problem" that they fixed later (i don't have an old one to compare)?
--did anyone else ever had this problem?

R.

[Mark Hammer]

I've made a couple and I certainly don't get it.  Sounds like something is wrong.

[Sam]

I remember getting similat artifacts using my old (stock) RAT II, but only with distortion and output knobs wide open. IIRC the effect was also clearly present while having the RAT fed by another distortion set at very high output.

Are you using active, or really hot pickups?

[blanik]

thanks Sam, i knew i wasn't dreaming... lol  actually i use a BD-2 in front of the Rat, and yeah, the problem is worst when i crank it up so i turned it down a little but i still get it when i plug straight in the Rat but i really have to strum hard and repetitively (i use a passive SD hot rails tele on my Fender and a passive DiMarzio Chopper T on my Squier) so it's not that hot (i bet my old LesPaul had more output than those)...

is there a cap or something i can change in the input stage of the Rat so it'll behave normally or is this inherent to all pedals??

R.

[col]

Are you using a battery or an adapter? I had a similar problem in another pedal and I was using a battery on a lead. I couldn't trace the problem until I decided to test the battery which was at 7.5v. When I changed it for a new one the pedal worked perfectly,

Col

[bassmeister]

I experience exactly what you describe with my DIY Rat. I play a Squier Stratocaster, and the Rat is supplied by a really cheap unregulated adapter (which has shown to work fine for other pedals). It works for a while when it's just been switched on, then the "bad" compression kicks in on the attacks. It's my own perfboard design, so I'm pretty sure I must have made a mistake somewhere. If it's a component error, I'm thinking it might be a drifting bias or something. I bought components from a not so trustworthy place, kind of an electronics junk yard charging the same as for new components... 

[Mark Hammer]

Quick question to you folks:  Does this compression happen when the Rat's gain is set low?  Because part of what lets the Rat sound like the Rat is actually the LM308's inability to deliver a huge gain/bandwidth product.  At low gains, you're not asking it to do something it can't do.  Indeed, you are basically providing something close to buffered unity-gain processing of a hot input signal.  At highest gain settings, though, you're asking the Rat to do the impossible on its own (gains in excess of 1000's), and beyond the impossible with a hot input signal.

Maybe the reason I've never experienced this compression is because I've never worked my Rat quite that hard.

[Sam]

Very interesing, Mark! I haven't been using mine for quite some time and can't really recall whether or not I got this compression effect other than with high gain settings.

Speaking of the Rat. I've found that connecting it into my Zvex SHO (set without any real boost) seems to enhance the distortion in some way. The sound gets clearer and gains some "bite" and IIRC it was less prone to feedback (?). Could it be an effect of the massive input impedance of the SHO? Abd might there be a way to somehow mod the output stage of the Rat to get similar "enhancements" in tonal characteristics?

[blanik]

thanks to everyone who replied... i tried my Rat with a new battery and it still does it but only with the LED diodes, it sounds OK with the 1N914... (of course i forgot to mention in my initial posting that i only got the bad compression when the controls were set very high and i thought it wasn't normal...) now i'm starting to think it's the two 12V LED diodes that suck the power when i play hard muted stuff (actually i only play that way to set up my sound    lol), is there a pair of diodes (other than the 1N914) that i can use instead of the LEDs to get a different sound than with the 914 (something more overdrivy and less fuzzy would be cool) and that wouldn't suck the power...

i actually did mine on perf board too and i'm quite certain it's set up allright (i tested each part after soldering it to the board and only used the right parts) and i've been using it for a while now and i noticed this compression effect recently while fooling around with it at max level... so i guess since this pedal is a 70s design, it might be normal to have some comp. with modern high gain settings...

hell, i even recorded an album with my Rat (and the BD_2) 
you can listen to a couple of songs on our MySpace page... i recorded the guitars myself in our reashal space with my tele, my twin reverb and a SM57... that's democracy for you LOLL (those aren't mastered yet and they're quite MP3 compressed but you can get an idea...)

http://www.myspace.com/frigidmusic

PS: the whole inquiery about the Rat is because i got the TP pcb and i wanted to know what was happening before making a second one (i already made the TP big muff... AMAZING sound, the orange squeezer (it's working perfectly but i'm not shure if it'll get on my pedalboard... whaiting for the Ross comp pcb to try it too...)
WARNING: making your own pedals can be addictive!!

R.

[col]

Try using normal 3mm LEDs as the 12v ones have a resistor built in which will be sucking power. Normal ones will light faintly when they are distorting,

Col

[blanik]

yeah, i put the 12V ones because i figured i would burn the regular 2V ones with the 9V of the battery, but was told later that at the clipping stage you don't get 9V anyway, much lower voltage... but still, i thought 2V would be pretty close to what's coming to the diodes...  anyway, it'll cost me 50 cents to try... 
but i'm not the "experimental" type so i prefer asking around before doing anything...

i would also like to know where to find info on how to put a switch on a Big Muff to bypass the tone section... (i've seen this switch on an old original one and i'd like to do this on my TP BMP)

R.