So, I am doing it.... An SLO inspired build ***completed with clips***

Discussion in 'Amps and Cabs' started by fusionbear, Sep 1, 2018.

  1. Hacksaw

    Hacksaw Time Warped Gold Supporting Member

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    Would you elaborate what are the suspect transformers? Thanks
     
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  2. fusionbear

    fusionbear exquirentibus veritatem Gold Supporting Member

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    Here is a quick clip of the build at bedroom volume:

     
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  3. fusionbear

    fusionbear exquirentibus veritatem Gold Supporting Member

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    For the tech guys out there, the mercury magnetics PT is rated at 600 mA on the secondary. Plenty of power available! Its the MSUPB-100-P. The OT is O100JM. Choke is a modern Marshall 250 mA, 3 hy.
     
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  4. louis

    louis Supporting Member

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    Ha !!
    -Right amount of thump!
    -Right amount of low juicy
    mids !
    -Right amount of chewyness!
    -Right amount of highs !

    Now we gonna have to reverse engineer a FusionBear take on a Soldano with some tweaks !! :D

    Well done Carl !! ;)
     
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  5. Fret-Shredder

    Fret-Shredder Member

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    Awesome sounding build. Nice chops too.
     
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  6. fusionbear

    fusionbear exquirentibus veritatem Gold Supporting Member

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  7. tone?

    tone? Supporting Member

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    Damn dude. Sounds awesome.

    Congrats.
     
  8. wntbtw

    wntbtw Member

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  9. fusionbear

    fusionbear exquirentibus veritatem Gold Supporting Member

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    Thank you! The good news is that I didn't do anything really different. I will explain so that anybody can tackle it.

    As for the circuit, I used the Avenger as the basis. The Avenger is the SLO without the crunch/clean circuit. Secondly, I eliminated the second cathode follower used as a recovery stage of the effects loop. On the first cathode follower, I eliminated the voltage divider on the cathode and just have a 100k to ground there and feed the tone stack. After the asymmetrical cold clip stage, which is the third triode, I used both a 330k to ground and the 2.2m to ground before the 220k grid stop resistor to keep the levels as close to stock into the first cathode follower since the clean/crunch impedance is eliminated. The power supply circuit had to be adjusted since I used Mercury Plexi PT and OT. The PT is the kind that requires a bridge rectifier. I used a dpdt standby switch that breaks the ac going to the bridge. This is much safer. Breaking DC is always hard on switches and causes arcing. But, I normally leave it on anayway. I am in the camp that does not like standby switches and prefers not to use them.
    I used two 385V/350uf in series for the plates (175uf total). The center tap goes to the middle junction there to balance the voltage between the two caps. The choke was taken from a plexi reissue Marshall and is the typical 250 mA/3Hy. type. The screens get two 500V/250uf in series with 220k resistors across them to keep them in check (125uf total). From there, I used a drop resistor to the PI that gets 500V/50uf. And from the PI it splits to two 15k's to the preamp. They each get 500V/16uf. I used the Metro loop. It is wired between the treble pot and MV. I feed its power supply from the PI/cathode follower node and used a 56k resistor to get the voltage in its proper range. I used the same resistors and caps that Soldano uses and sourced them from Mouser electronics.
    I used EL34'S so, the screen grid resistors are 1k. I used 1 ohm on the cathodes to ground so I can check the current. I used a 50k pot on the bias circuit so I have plenty of range. I may try kt77's after these wear out and see how they do. Lastly, I added a .001 over a 220k for a fixed resonance on the 8 ohm tap to the negative feedback. In the presence circuit I used the "old-school" 5k "scratchy" type as it gives better taper. I prefer that circuit in most of my builds. I used PEC pots throughout, but I always disassemble them, clean and relube before using them. I got a few duds before, so I always double check them before I use them. I think that's it...
     
    Last edited: Oct 6, 2018
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  10. louis

    louis Supporting Member

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    Lets call it Carl's Secret Sauce !:D
     
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  11. fusionbear

    fusionbear exquirentibus veritatem Gold Supporting Member

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  12. Sirloin

    Sirloin Supporting Member

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    Nice box! So @fusionbear , how does the high gain channel clean up with the volume rolled back?
     
  13. fusionbear

    fusionbear exquirentibus veritatem Gold Supporting Member

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    That's a good question. I have time to play with it tonight. I will let you know...
     
  14. louis

    louis Supporting Member

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    Forgot to ad that I think it's very generous of you to share your building process!!........Says a lot about you !!
    I'm no tech but I'm sure some of us will be happy to have their future amp build by you !!

    Class act for sure !!;)
     
  15. guitarranch

    guitarranch Supporting Member

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    Got to hear the "Sloth" this evening at my good friend Carl's(Fusionbear's)house after several hours of burn-in time. The amp sounds absolutely amazing.It has the most pleasing overdrive and tone that I've heard in quite some time and ranks as one his best builds.It's the best of both worlds and made me wonder why Mike Soldano didn't think to include this type of build among his line of amps. Even the low sensitivity input sounds very organic and musical. We had a great time this evening talking,listening to music while Carl installed old Gibson T-tops in my R8 and USA Dean Michael Schenker V. We tested a Fortin Grind into the low sensitivity input of Carl's hybrid SLO and were quite pleased at what this pedal does. All in all it was a good evening for two tone junkies.
     
    Last edited: Oct 6, 2018
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  16. fusionbear

    fusionbear exquirentibus veritatem Gold Supporting Member

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    Final Pics....

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    @Sirloin had asked if it cleans up well with your volume pot on your guitar. The answer is: It depends. If you have the gain past noon, it cleans up ok, but not like a plexi or a trainwreck. Below noon and it does sufficiently well.
     
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  17. FourT6and2

    FourT6and2 Member

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    Sounds great!

    What caps did you use for tone stack treble cap and whatnot? Look like multi-layer ceramics?
     
  18. Advisable Owl

    Advisable Owl Member

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    That PT is pretty stiff on the secondary compared to most Marshall's correct?
     
  19. fusionbear

    fusionbear exquirentibus veritatem Gold Supporting Member

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    Murata Multi Layer 1kv.

    Curious as to what you used in your builds. I liked what Larry from Larry amps had to say on one of your build threads at rig-talk.
     
    Last edited: Oct 8, 2018
  20. fusionbear

    fusionbear exquirentibus veritatem Gold Supporting Member

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    Yes, very stout! I checked with Patrick @ Mercury to be sure. This is what you want with this circuit. The preamp does the tone shaping and the power amp section delivers that to your cabs.
     
    Last edited: Oct 8, 2018

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