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Messages - syndromet

#16
Amplifier Discussion / Re: What have I got here?
February 24, 2009, 07:53:56 AM
To me it looks like something worth fixing....
#17
Hi.

Drew this up for you, but I'm not really sure you are gonna understand it.


I think you should use DPDT relays, So that you can have true bypass on all the effects. Let me know if you need some explaining. ;)
#18
relay switching is definitivly the way to go. You should also have a preamp on the clean side of the switch, so that you hit the preamp with the gain it prefers. It should also allow some toneshaping to make the amp more versetile. Something like an inverted lm072 with a tonestack or something.
#19
http://www.andrewsamplab.com/Cap.htm

This is ofcource some guy trying to sell his services, but it does say how old caps can affect you tone and stability of your amp.

For the pots, I sugest to first spray them with compressed air, if they are not sealed. Then you get a can of deOxit and spray the guts of the pot. If the pot is seales, let a lot of deOxit run down the shaft, and twist the knob back and forth several times. Do this a couple of times, and if that doesn't help, change the pot.
#20
I say you replace one transistor. If it works, you have 15$ to spend of something fun. If not, you have to replace the 3 others anyway. Recapping is always a good idea on old stuff, especially the electrolytics. For cleaning pots you could try compressed air. It has done wonders for me.
#21
Preamps and Effects / Re: Best / Favorite DI
January 09, 2009, 08:42:52 AM
I don't really see why you would want a DI in that setup at all? You are not running directly to the PA, and I suppose you are not going to run long lenghts of cable. The Digitech don't have a balance input, wich means your signal won't be balanced anyway. That means that you'll only change the impedance of your signal, wich means that the digitech won't see the signal it was designed for. I bet a DI in your chain will do more bad than good, and I bet something like this will bring you closer to what you're looking for.

#22
Tubes and Hybrids / Re: First tube amp.
December 04, 2008, 03:04:19 AM
It sounds pretty good, especial the cleans and light breakup are good. I find the distortion to be a little to bright, but I guess that can be fixed with a little tweaking. To be honest, I was expecting this to beat my sansamp/Lm1875 combination, but I don't think it does. Comes pretty close, though.
#23
Tubes and Hybrids / First tube amp.
December 03, 2008, 03:13:06 AM
Not exactly a hybrid, but I like to show off.  ;) Here is my first venture into high-voltage tube stuff. High Octane from AX84.

Pretty happy with the externals. Got to find some miniature chickenheads, though.


Messy, as always.....
#24
Preamps and Effects / Re: An universal guitar preamp
November 26, 2008, 02:50:32 AM
Looks and sounds great! Too many knobs for my liking, but it looks great.
#25
Amplifier Discussion / Re: Pictures
August 21, 2008, 05:14:20 PM
looks good. How did you construct the cabs? I like the wheels....
#27
Amplifier Discussion / Re: Portable Keg Amp
August 15, 2008, 09:10:31 AM
Depends on what sound you are looking for.
Try the little gem or the ruby st www.runoffgroove.com
Both sounds great.
#28
Amplifier Discussion / Re: LM386 based guitar amp
July 26, 2008, 02:51:58 PM

My little gem. Great sounding LM386 amp. tatally love it, but rearly use it, since it is too loud!!!!
#29
Preamps and Effects / Re: preamp for LM3886?
February 27, 2008, 04:10:11 PM
Quote from: darwindeathcat on February 27, 2008, 01:59:39 PM
Quote from: syndromet on February 27, 2008, 06:58:20 AM
II would drop the buffers, and use the preamps straight, just for simplicity. I think most of the ROG designs buffer the signal anyway.

    Actually, following teemuk's advice I was thinking that I would extract the buffer portion of the ROG designs, and put a single buffer in front of the switch (input buffer in my schematic). I think that most of the ROG designs use a very similar buffer. Either way, I think a simple fetzer valve can be used to replace the stock buffer in any of their designs (I know this is definately true for the ruby). I think your right about diching the output buffer.

This sounds like a good idea. Using the fetzer valve will also give you the possability to boost the signal to push the preamps a little harder. Maybe set the fetzer to unity gain, and have in switchable to +20dB or something. A lot of marshalls have this option, and it does change the sound quite a lot. You could ofcource use a pot, and label it "pregain gain" ;)
Quote

Then, I guess I'd have at least a gain pot per channel, and perhaps a couple of switches (for grit and whatnot, depending on the circuit I would choose). This way, you can have each channel adjusted the way you like it, and when you switch into it, you don't have to fiddle with any pots. Perhaps a volume pot per channel is not necessary if I have a master volume control right before the power amp? I'd stick a tone stack after the preamp stage, so it would be a common setting.

This is a hard one. What makes the JFET emulators sound somewhat simular to the emulated circuit has a lot to do with frequenzy shaping and tone controlls. Leaving the tonestack after the circuits, and finding the values wich sounds good with all preamps could be a PITA. Even if you find a tonestack wich does the job great, you will probably loose some of the caracteristics of the preamp ith just one tonestack.

Every amp has some settings that make the amp sound like what it does. The tone stack of an overdriven Marshall is usualy set to boost the mids, while an AC30 is set to boost treble. The same tonestack settings would probably not sound great at both clean and OD, wich is why I hate amps with 2 or 3 channels and only one tonestack. If you tweak the sound to be great for cleans, it will usualy sound shitty on OD. Tweak it for OD and the cleans will suffer. If I were to build something like this i would leave the full tonestack on all the preamp cicuits. It would be a hell of a lot of pots, and make the offboard wiring a nightmare, but I would be able to get my favourite sounds by switching, and without having to tweak the knobs in the midle of a live set.

It would ofcource be possible to tweak the circuits to sound just the way you want it with thepost preamp tonestack set at the same possition, but that would recuire some serious breadboarding and comparing between the preamps.
Quote

   The easiest switching would definately be a double gang rotary (or a dpdt if you only have 2 channels), and wire it to switch like in my schematic. Each preamp circuit would always be getting power, but would not be connected to a signal at it's input or output unless switched to. A footswitch would be very useful, but I have no idea how they work, so I couldn't even think about designing one!

There is no doubt that a rotary sitch is the way to go. Futurlec carries a lot of different ones, so you will probably find something usefull there.

Footswitching could be done pretty easily with latching relays. I once planned to do what you described here with the rotary switch, and my plan was to have the last position on the switch be for footswitching, and sending the signal to relays.
So you would have one position for Clean, one for od, one for distortion and one for footswitch.
Quote
   Right now I'm think of building a 4 channel setup with the channels being 1)Proffessor Tweed 2)bassman ruby 3)Odie 4)Clean ...

Maybe a lm3875 for the power amp?
great choice of preamps. Personally i would dropp the BM Ruby for an eighteen, simply because I think the Proffessor tweed an the BM Ruby sounds a lot like each other. I also think the eighteen is the best pedal designed by rog ever...

I would personally go with the 3886 if I were to use one of the lm chips. I recomend you to look at the kits at www.41hz.com . I built an AMP5, and it sounds great with guitar. There is almost no need for a heatsink, and they recuire a lot less power per watt than the lm chipamps. This means that you will be able to build a lighter and more portable amp with a higher output.



Hope i didn's scare you completly of with my rambling. I'm really looking forward to see how this turns out.
#30
Preamps and Effects / Re: preamp for LM3886?
February 27, 2008, 06:58:20 AM
I haven't read through the hole thread, so forgive me if my answer is a bit off.... 8)

The idea you posted over here seems to be very good. if I was to build something simular 8 (wich I might..), I would drop the buffers, and use the preamps straight, just for simplicity. I think most of the ROG designs buffer the signal anyway.

As for wiring it up, I think the rotary switch option sounds good. You will however get a lot of pots, since every preamp will need it's own sets of controlls. that is great, if thats what you want. Otherways I waould listen to Teemuk, and make the "sound altering" components in one pre switchable.