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Ampeg PF-20T to (power) amp

Discussion in 'Amps and Cabs [BG]' started by Zbysek, Nov 21, 2018.


  1. Wasnex

    Wasnex

    Dec 25, 2011

    That's the calculator I usually reference as well...couldn't find it for some reason; thanks. I figured @Downunderwonder might still relate to +4dBm like me ;).

    From what I have read, the XLR input works with a dynamic mic, but the overload level suggests it is flexible enough to handle line level fine.
     
  2. Now I got it. Peak to Peak. Cheers.
     
    Passinwind and Wasnex like this.
  3. Zbysek

    Zbysek

    Mar 23, 2017
    Czech Republic

    The manufacturer states "max. voltage 10 Vpp" (impedance 33 kOhm) for the FX return. The same for the XLR input is 25 Vpp (impedance 100 kOhm). Do I understand correctly that the higher max. voltage means that the XLR would sustain higher overload in comparison to FX return? Thank you.

    MARKBASS | Products | Little Mark III
     
  4. Zbysek

    Zbysek

    Mar 23, 2017
    Czech Republic
    Is the level of transformer balanced line affected by setting of the Ampeg's master (volume) knob?
     
    Last edited: Nov 23, 2018
  5. Zbysek

    Zbysek

    Mar 23, 2017
    Czech Republic
    I have this feature on my EBS Microbass II preamp. I have discovered it's usefullnes just recently. I am using it as a dry/wet blend knob for my effects...
     
  6. Zbysek

    Zbysek

    Mar 23, 2017
    Czech Republic
    Correct. My assumption is that the Transformer Bal Out will provide more saturated/overdriven sound.

    I don't plan to split the signal as it seems to be an unnecessary complication.

    I plan to send the Transformer Bal Out to FOH and feed the LM III from the Preamp Out. The reason being that I like less overdriven sound for on-stage monitoring purposes.

    I might also send the FOH second line from Little Mark's DI.

    But I will experiment with the other possibilities as well.
     
  7. ficelles

    ficelles

    Feb 28, 2010
    Devon, England
    It is, but not as much as you'd expect - like many tube amps most of the action is in the first half of the master volume, beyond that you are adding more overdrive than level. It didn't overload the LM input at all, although I didn't dime the input level.
     
    Zbysek likes this.
  8. Zbysek

    Zbysek

    Mar 23, 2017
    Czech Republic
    THX
     
  9. Passinwind

    Passinwind I know nothing. Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics
    Yep, that's one of my main uses as well. In one of my DIY preamp builds I also used an EFX send pot, and a bypassable FET "sweetener", with separate master for the sweetener. Sort of like a built in Tube Screamer circuit that can go various places in the chain. That works pretty well for warming up digital time domain effects, or for a mild clean/dirty thing with a blend control.

    I'm especially interested in this thread since I'm about to try my hand at a few tube amp builds. Should be fun after doing mostly onboard preamps for the last few years. Love the feature sets on the PF-20T and PF-50T.
     
    Zbysek likes this.
  10. Zbysek

    Zbysek

    Mar 23, 2017
    Czech Republic
    Me too!
     
    Passinwind likes this.
  11. I'm also interested in this thread. I have a PF-50T that I could use as a preamp. I have a Soundstream DA-2 power amp that has balanced XLR inputs, so I think it should be a simple connection. I'm going to give it a try.

    The other setup I will probably test is using the PF-50T with one cab and running the line out into the FX return of my PF350 to power the other cab. That FX return is unbalanced, so what's the simplest/best way to make that conversion? I have a passive DI on hand that I could use, but that's intended to work in the other direction with an instrument on the unbalanced side.
     
    Zbysek likes this.
  12. Zbysek

    Zbysek

    Mar 23, 2017
    Czech Republic
    Please, let us know your experience after you try either way...

    This issue has been discussed above. There are two lines of thoughts: 1. one needs "thingies" to make it work, 2. no "thingies" necessary...
     
  13. Wasnex

    Wasnex

    Dec 25, 2011
    That's how I interpret it. The Mark Bass manual does not really clarify what the expected signal level is though, so we are drawing some inferences that may or may not be correct. The XLR will safely handle a line level signal, but that doesn't mean it will sound great or work well being driven by the PF20T Transformer Bal Out.
     
    Zbysek likes this.
  14. Wasnex

    Wasnex

    Dec 25, 2011
    The problem with sending Preamp out to the LM and Transformer Bal Out to FOH is you will not know how distorted the sound is at FOH. The Transformer Bal Out signal will be at least as distorted as the signal at the Preamp Out, potentially much more so. Definitely run some experiments :thumbsup:.
     
    Zbysek likes this.
  15. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    In the end, that's probably the only practical difference.
     
    Wisebass likes this.
  16. My initial thought was that I should find out what the input impedance of the PF350 EFX return is, but.... it's expecting line out from effects pedals, so it seems like itshould be fine.
    I'm going to start without any "thingies" - just an XLR to 1/4" TS cord.
    Will report back after experimentation:thumbsup:
     
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  17. Zbysek

    Zbysek

    Mar 23, 2017
    Czech Republic
    That' true. I will experiment. My goal is to always give FOH two signals: one clean and one overdriven. This will allow the FOH guy to blend them or even mute one if he finds the other one much better...
     
    Wasnex likes this.
  18. Zbysek

    Zbysek

    Mar 23, 2017
    Czech Republic
    My understanding of the issue is that you need to convert ballanced signal to unballanced signal...some say
     
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  19. Wisebass

    Wisebass

    Jan 12, 2017
    Lost in Space
    Balanced DI out (XLR) into poweramp input (1/4")

    :D

    greetings

    Wise

    edit to add: lots of information about the signals, cables and thingies on only two pages!
     
    Last edited: Nov 23, 2018
    Zbysek likes this.
  20. I just read through that thread paying close attention to what agedhorse had to say, and it still seems to come down to experimentation to see what works.
     
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