Fuchs ODSslx channel switching question...

Discussion in 'Amps and Cabs' started by bluesmostly, Mar 4, 2006.

  1. bluesmostly

    bluesmostly Member

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    Maybe I am a little dull when it comes to figuring out the features of this amp:horse

    but after a few months of playing it I am still having trouble getting a balance between the clean and dirty channels.

    I like the clean channel to be clean, and lots of gain on the dirt channel. The problem I am having is that the clean ch usually ends up being louder than the dirt and I like it to be the other way around, esp in a gig situation...

    After all this time, I am not even sure I really understand how all the knobs work and interact with each other... :confused:

    Help!!

    BTW, I totally love this amp!!!:AOK
     
  2. tedjac

    tedjac Guest

    Do you have the manual? If not, it is downloadable.

    I just got my amp yesterday (ODS30SLX) and I have had really good luck getting some great tones. I haven't tried to balance the channels yet, but according to the manual that is what the OVERDRIVE OUTPUT control is for. You get the amount of distortion from a combo of the GAIN control and the OVERDRIVE INPUT control. I would set the GAIN for desired clean and then set the OD INPUT for anount of distortion, then use the OD output to balance the two while using your footswitch to toggle back and forth. Keep in mind that the pull out pots and tooggle switches greatly effect the character of the tone. You also have the ACCENT control to add a little bite to the OD if you desire. If you aren't getting enough distortion with the GAIN set for your clean preference, you may need to adjust the internal pot to increase the amount of distortion through the OD channel. I haven't opened up the amp yet, so I can't tell you excactly where that pot is... but someone with more experience will chime in here and help... I'm sure.

    Anyway... aren't these amazing amps??

    Ted
     
  3. bluesmostly

    bluesmostly Member

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    Thanks Ted. Yes they are amazing amps!

    I do have the manual and I read thru it a couple of times a few months back. It didn't help that much as I recall. perhaps I have to read it again.

    I have the gain (far left knob), set at around 9 o'clock and the output control dimed. I still have volume issues and less gain in the dirt channel. If I push the gain control the clean channel gets too dirty and loud...

    internal pot adjustment you say... :rolleyes:
     
  4. devbro

    devbro Member

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    Odd, I have the opposite problem with my 50. I'm in the process of getting to the bottom of it now. My od channel will break windows but the clean is feable.

    I figured out a workaround until I can play my friends tp see if mine is defective. I run a short cord between the effect loop out an effect loop in. I can then use the seffect end and return volume to boost the clean.
     
  5. jmadill

    jmadill Gold Supporting Member

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    I've only had mine since Monday, but here's what I figured out. I could be wrong, and am open to corrections, but through this understanding, I was able to overcome the situation you describe.

    Essentially, there are 3 stages to the amp. Preamp, OD, and Amp. Gain controls output of the preamp. OD Input is essentially the gain on the OD section, whereas the OD Output controls the volume of the OD stage.

    When you are in "clean" mode, the preamp feed the amp stage. When you are in OD mode, the preamp feeds the OD stage, and then the OD stage feeds the Amplifier stage.

    With the OD off, set the gain so that you have the sound you want for the clean sound. Then, adjust the master so that you have a good volume for that channel. Turn OD on, and set the OD input so that you have the right amount of dirt for the OD channel, and then adjust the OD output so that the volume is appropriately matched to the clean channel.

    If the OD channel is too low a volume, and the OD output is maxed, it is possible that the OD input is too low. Adjust between the OD input and OD output until you dial it in.

    I hope this helps you.

    -jm
     
  6. aeolian

    aeolian Member

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    I run my input gain around halfway. And the OD in about halfway. What this means is that even with the OD out dimed, if you turn the master down too low, the clean is louder than the OD. Andy suggested running a lower input gain setting and higher master volume setting. Since you have your input gain lower, you ought to be able to get it too work. Scott will chime in with the relationships of the newer control scaling. Maybe he has some suggestions.
    Another thing to try is put some effects box in the loop set to serial but with it's controls turned down. I used to do this with my Boogie and it helped a lot.
     
  7. Berre

    Berre Member

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    when I put the input gain all the way up on my ODS 50 SLX to get a crunchy sound on the clean channel, then the lead channel gets extremely noisy when i switch to it (almost microphonic noisy)
    OD input and OD output are round 12 o'clock.
    master volume around 9 o'clock.....

    does anybody else here has that same problem !?

    could you guys check it out on your amps please ??

    I allready emailed Andy to tell him about this problem, he advised me to replace the input gain tube but the problem stays.....

    please advice guys !!

    bert
     
  8. bobbymack

    bobbymack Supporting Member

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    I'm waiting to take delivery of my ODS30, but the advice above sounds exactly correct, and is the way I'd envisioned setting the channels based on reading the manual. Are you guys saying this method doesn't work???
     
  9. bluesmostly

    bluesmostly Member

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    Thanks jm, this is how I understand it to work, but with both the Input and output on the OD channel high, and the gain at 1/4, the clean is still louder most of the time.
     
  10. bluesmostly

    bluesmostly Member

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    Yep, that is the way I understand it too and I haven't got it quite right so far...

    I am going to try Aeolain's suggestion of lowering the input and turning up the master to see if that changes the relationship between the channels...

    PS. congrats on your purchase bobbymack, you are going to love this amp !!
     
  11. abergdahl

    abergdahl Member

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    Most (all) *D* style amps are SINGLE channel amp with a post preamp, pre power amp (i think) OD circuit. I practice this means that the first volume will affect the OD sound. It is correct that od ín regulates amunt of gain (together with first volume) and the OD out is the level put out from OD (DOH). I find that my Mystic Blues is set so that is almost clean without the OD circuit and with OD i set out to slightly boost the volume (and amount of gain to power amp). So basically is a one channel amp with a series OD stage that you can switch in and out of the suígnal path. Approach the amp as that and NOT as a two channel amp and life will be much easier :AOK
     
  12. devbro

    devbro Member

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    There's an internal trim pot that controls the amount of gain sent from the clean channel to the OD channel. According to the manual, this is set at about 1/3 from the factory. If your OD channel is not loud enough, you could increase this setting. You must remove the amp from the case to access this trim pot. Be very careful removing the chassis from the case due to the extremely high voltage stored in the capacitors. A simple way to bleed the caps is to play a power chord while the amp is on, and then while the chord is ringing, unplug the amp. You'll hear the volume slowly fade away - this is the caps bleeding off stored voltage. There are better more technical ways to bleed caps, but this works pretty well for us non-techies:p
     
  13. aeolian

    aeolian Member

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    Devro, that trim pot sets the gain, not the volume. For those who want a lot of gain out of the OD channel, crank it up. You can then lower the input gain which will make balancing the channels easier as Anders says. For me, I prefer a less gainy sound, so I keep that part down. The amp seems to have more articulation that way. Lot of options depending on the style you're after. Since you have an SLX version, it might be worth a message to Scott. He must be busy or he would have jumped in here.
     
  14. devbro

    devbro Member

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    I think that's exactly what he's trying to do - balance the channels. So if you increase the input gain via the trim pot can you then lower the input control or are they essentially doing the same thing?
     
  15. scottl

    scottl Member

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    The internal gain control is just a voltage divider seperating the channels. So it does control the gain that feeds the OD channel. By corollary, it also controls the volume to some extent. Half way should be more than enough........

    If anyone has any questions about balancing the channels and just can't get it right, email me.

    Hey Steve... busy is the word.....

    Scott
     
  16. willhutch

    willhutch Member

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    I had this same problem until Andy Fuchs did a demo in my hometown and showed me the trick: Turn up the master volume. With the MV around noon, you should find that you can get an appropriate balance between clean and dirty using the input level and distortion level controls.

    Andy dialed me in with the MV at noon, the clean input level around 9 o'clock, distortion gain at 3 o'clock and distortion level around 11 o'clock.

    Also of interest, he set the EQ controls all fairly low, 8-11 o'clock.

    Give that a go.
     
  17. bluesmostly

    bluesmostly Member

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    thanks Will, I'll try that!
     
  18. bluesmostly

    bluesmostly Member

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    Tried playing around with the master volume up and the input lower. It does work better for balancing the volume, but still not perfect when it comes to breakup and gain levels. Plus the overall volume is louder than I can use it for most applications.

    Gosh this amp sounds good loud!! :cool:

    ... just sent Scott a pic of the guts and he is going to coach me to do something or other in there...
     
  19. tedjac

    tedjac Guest

    I totally agree with the loud sentiment!! My problem is that I live in an apartment! At just about the point the amp really starts to come on... the volume is just too loud for my apartment.

    I have four 6V6GT power tubes in this pup. Will it work with just two? Will operating with only two actually lower the volume? It will still be putting out about 15 watts... plenty of wattage to get loud fast. Will running it with only two harm the amp in any way? What about running 5751 pre tubes in both V1 and V2... will that lower the volume that it starts to get good at?

    Just curious...
    Ted
     
  20. scottl

    scottl Member

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    Thanks Dave! We need to adjust those trimmers to taste...

     

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