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  • Crate v33 to Soldano SLO mods

    First off all some warnings:

    I am not advocating or advising that you perform this mod to your amplifier. Amplifiers have very high voltages stored in them that can kill you. This is the case even AFTER YOU TURN OFF YOUR AMP AND UNPLUG IT. DO NOT PROCEED WITH THIS MOD IF YOU DO NOT KNOW WHAT YOU'RE DOING. If you're just curious what it sounds like, there is a link to a clip at the bottom of this post.

    If you don't know what you're doing, do not open your amplifier up and do not attempt this. In addition to possibly killing yourself, there is also the possibility that you could destroy your amp and render it useless. My advice is that if you don't know what you're doing and don't know how to trouble-shoot amplifiers that you DO NOT ATTEMPT THIS MOD. Have I said this enough yet?

    Please don't PM/email me and ask if I think you have the skills to do this mod. Only you know the answer to that, I have no way of knowing. This mod documents what what I did and how I did it. If you do decide to do it yourself, it's all on you!

    NOTE: Steve Ahola has posted his own version of this mod that saves the clean channel, unlike my mod which turns the v33 into a single channel amp. If that's something you desire, you should read his mod before this one... actually, you should read his anyway as it has more information about what's going on then mine does. Steve's post is on the second page of this thread.


    I recently modded my v18 to the Soldano SLO pre-amp design using the instructions found here:

    http://www.thegearpage.net/board/showthread.php?t=464873

    Steve Ahola is the person who created this mod for the v18 deserves full credit for it. I adapted most of his work to the v33 but never would have attempted it (or even thought of doing it) had Steve not first done his work.

    These mods sounded excellent in the v18. So much so that I wanted to do a similar mod to the v33. The v33 has a similar pre-amp as the v18, with the exception of having a "clean" channel. The "clean" channel on the v33 isn't really a clean channel, it just switches the other half of v1 out of the circuit so the pre-amp has less gain. The clean channel on the v33 actually sounds pretty good stock, so if that's a consideration for you, don't do this mod. I never used the clean channel.

    Also, if you performed R4/R77 resistor swap mod prior to this, you will need to put R4 back to a 470k resistor (R77 gets removed).

    The v33 has two relays to support the channel switching. I removed both relays and hard wired the connections in the pre-amp using jumpers. This made the amp a single channel amp. I don't have a layout diagram, so I can't really adaquately describe how I jumpered the switches. Here is an attempt:

    R8 gets removed and jumpered (or just jumpered) in the mod. I thought I was going to have to jumper from C7 to R11, but it turns out the schematic is wrong and that is connected by a trace on the board. Check it for yourself to be sure.

    JUMPERS:

    Jumper from the junction of R4 and C5 to pin 2 of CW2 (pin 2 on the schematic). This takes care of what Relay 1c used to do. Look at the schematic for details.

    Jumper from the middle of Cw3 to the top of R18. Again, check the schematic.

    Since you will remove R5 and relay 1, CW1 is completely out of the circuit and can be used for later mods if desired.

    As far as volage ratings for replacement parts: Look at the parts you are replacing and replace with similar ratings. If you don't know how to do this, you shouldn't be messing around with an amplifier. oke:

    OK, here are the part values for swapping and removal. Please note that I only did the pre-amp and not the power amp mods that Steve did (and I did in my v18). Also, the solder used in the amp seems to have a higher melting point then regular solder. I found myself flowing solder into the joint, then using desoldering braid to wick the solder out. Don't force things, go slow. If you pull a pad off the board you will need to jumper back to the last previous good point on the board. Do this too many times and you really end up with a mess!

    More follows...
    --
    Wagdog
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    "Albert King could blow Eddie Van Halen away with his amp on stand-by"
    - Joe Walsh


    Good Transactions: Doctor Morbius(x2), Cadfael, bg-pups.com(x2), DCinDC, twotimingpete, dwerlin, DaleH, chqtarzan, sxyryan, lowbrow, albertus, vintage clubber

  • #2
    Here we go...

    Remove Relay 1 and Relay 2. This is hard. I used a cutting dikes and crunched them up, then removed the pieces. It was messy. Once you do this you made your v33 a single channel amp.

    I did the JUMPERS section above, then these changes:

    R2 220k
    R3 1.8k
    C6 1uF
    C1 .02uF
    R5 Remove
    C4 Jumper
    C5 .002uF
    R77 Remove
    R91 470k
    C90 Remove
    R8 Remove and jumper (or just jumper)
    R75 100k
    R9 Bypass with .001uF
    R78 1.8k and bypass with 1uF
    R11 470k
    R12 39k
    R15 1.8k
    C13 1uF
    R14 150k - you can go as high as 330k here for more gain but it isn't neccasary. You can also leave it stock.
    R17 47k - you will have to unsolder one end of this and solder in a 15k in series for an actual value of 48k. Leave it standing up, like an upside down V.
    R21/C17 Jumper - I didn't do this on the v33 but did do it on the v18. I like it better without the jumper.
    Add a "bright cap" .001uF from pin 2 of CW2 to pin 3 of CW2. On my v18 I put it on a switch so it can be turned off.

    If you want to do the power amp mods, take a look at the values Steve used and how he re-routed everything. I found that the v33 sounded so nice after these changes that I didn't want to bother.

    I have triple checked my notes against this list, I think it's correct. However here is what I recommend you do: Get Steve's mods from the link above.

    Get the v18 schematic from Steves site (in the link above). Draw out the v18 mod on the schematic, and at the same time follow the mod on a v33 schematic, making the mods. What I mean is do the mods in pencil on the schematic. Then check my work above and see if it matches. You are doing this at the risk of destroying your amp, so make sure you're comfortable doing these changes.

    The clip below is recorded using the modded v33/SLO into a 4x12 cab loaded with Eminence Legends. I'm playing a '74 strat with bg-pups.com v60's. This is recorded as-is with a zoom h2. I sliced and diced a bit using ntrack but added no effects or anything like that.

    http://wagner-usa.net/cratev33SLO-74strat_mixdown01.mp3

    Clip rundown: A bit dirty, then clean, then full preamp gain at the end.

    Tubes in the amp at the time clip was recorded: v1: 12ax7, v2: 12at7, v3: 12au7 - I would imagine more gain coule be had by going with a 12ax7 in v2.
    --
    Wagdog
    Check out Lunar Commander on:
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    "Albert King could blow Eddie Van Halen away with his amp on stand-by"
    - Joe Walsh


    Good Transactions: Doctor Morbius(x2), Cadfael, bg-pups.com(x2), DCinDC, twotimingpete, dwerlin, DaleH, chqtarzan, sxyryan, lowbrow, albertus, vintage clubber

    Comment


    • #3
      Sweet! I think the clean, even with the mod is great, very bluesy, clear but not sterile...

      Otherwise, same kind of "freed the amp" effect as the V18 mod ya did.

      I'm gonna try it on my V18 soon...

      Comment


      • #4
        Sweet! I think the clean, even with the mod is great, very bluesy, clear but not sterile...

        Otherwise, same kind of "freed the amp" effect as the V18 mod ya did.

        I'm gonna try it on my V18 soon...


        I *really* like the cleans on the v33 now. LOTS of headroom too - no question that I could play this amp clean and plenty loud.
        --
        Wagdog
        Check out Lunar Commander on:
        iTunes App Store
        Google Play

        Lunar Commander Lite - FREE!:
        iTunes App Store
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        "Albert King could blow Eddie Van Halen away with his amp on stand-by"
        - Joe Walsh


        Good Transactions: Doctor Morbius(x2), Cadfael, bg-pups.com(x2), DCinDC, twotimingpete, dwerlin, DaleH, chqtarzan, sxyryan, lowbrow, albertus, vintage clubber

        Comment


        • #5
          I *really* like the cleans on the v33 now. LOTS of headroom too - no question that I could play this amp clean and plenty loud.


          Yeah...Makes me just want to add a tweak to my V18...
          How hard would it be to do the same gain diversion on a V18 as the V33 has?
          Just put a button or a switch for it somewhere...

          Comment


          • #6
            Link for schematic doesn't work for me. Can you check it?

            Comment


            • #7
              Yeah...Makes me just want to add a tweak to my V18...
              How hard would it be to do the same gain diversion on a V18 as the V33 has?
              Just put a button or a switch for it somewhere...


              Not sure what you're asking. They are pretty much identical right up through the preamp (now anyway). There is an additional switch for the midboost and presence (treble boost really) in the v33 that could easily be added to the v33. See the schematics for those details.
              --
              Wagdog
              Check out Lunar Commander on:
              iTunes App Store
              Google Play

              Lunar Commander Lite - FREE!:
              iTunes App Store
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              "Albert King could blow Eddie Van Halen away with his amp on stand-by"
              - Joe Walsh


              Good Transactions: Doctor Morbius(x2), Cadfael, bg-pups.com(x2), DCinDC, twotimingpete, dwerlin, DaleH, chqtarzan, sxyryan, lowbrow, albertus, vintage clubber

              Comment


              • #8
                Not sure what you're asking. They are pretty much identical right up through the preamp (now anyway). There is an additional switch for the midboost and presence (treble boost really) in the v33 that could easily be added to the v33. See the schematics for those details.


                You said:
                The "clean" channel on the v33 isn't really a clean channel, it just switches the other half of v1 out of the circuit so the pre-amp has less gain.


                And I'm asking-

                Could you add the same kind of "channel switch" to a V18?

                Comment


                • #9
                  Link for schematic doesn't work for me. Can you check it?


                  Actually it does. You'll get the 404 error, click in the address bar and hit enter. For some reason the gear page doesn't like redirects from other sites. Weird, but that's the way it is.
                  --
                  Wagdog
                  Check out Lunar Commander on:
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                  Lunar Commander Lite - FREE!:
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                  "Albert King could blow Eddie Van Halen away with his amp on stand-by"
                  - Joe Walsh


                  Good Transactions: Doctor Morbius(x2), Cadfael, bg-pups.com(x2), DCinDC, twotimingpete, dwerlin, DaleH, chqtarzan, sxyryan, lowbrow, albertus, vintage clubber

                  Comment


                  • #10
                    You said:


                    And I'm asking-

                    Could you add the same kind of "channel switch" to a V18?


                    Ah.

                    Probably, it wouldn't be that simple though. The v33 accomplishes this using 2 relays (4 switches) which remove part of v1 from the circuit and also the other components that go with it. You could conceptually do this, but it would be a lot of work.
                    --
                    Wagdog
                    Check out Lunar Commander on:
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                    "Albert King could blow Eddie Van Halen away with his amp on stand-by"
                    - Joe Walsh


                    Good Transactions: Doctor Morbius(x2), Cadfael, bg-pups.com(x2), DCinDC, twotimingpete, dwerlin, DaleH, chqtarzan, sxyryan, lowbrow, albertus, vintage clubber

                    Comment


                    • #11
                      Ah.

                      Probably, it wouldn't be that simple though. The v33 accomplishes this using 2 relays (4 switches) which remove part of v1 from the circuit and also the other components that go with it. You could conceptually do this, but it would be a lot of work.


                      It doesn't seem like a lot of work, unless you're oversimplifying or leaving something out. Compared to the entirety of the SLO mod, it seems doable. Also, how would it work out if I changed part of V2 similarly, for another "channel"(by crate's definition)? Would it be too quiet, would the tone stack not work out, or would it work?

                      Comment


                      • #12
                        Yeah...Makes me just want to add a tweak to my V18...
                        How hard would it be to do the same gain diversion on a V18 as the V33 has?
                        Just put a button or a switch for it somewhere...


                        The beauty of the SLO mod is it cleans up at low gain, or even with guitar volume turn down, no channel switches used. That is why this mod is so impressive on the v18. And now Wagdog has the same, single channel configuration on the v33, with twice the power amp...

                        Great job Wagdog! I read with interest how you "REMOVED" the relays!

                        Comment


                        • #13
                          The beauty of the SLO mod is it cleans up at low gain, or even with guitar volume turn down, no channel switches used. That is why this mod is so impressive on the v18. And now Wagdog has the same, single channel configuration on the v33, with twice the power amp...

                          Great job Wagdog! I read with interest how you "REMOVED" the relays!


                          Ha ha, yeah, the divide and conquer method, aka the crusher! I tried to get them out peacefully at first, honestly, but there were too many feet to unsolder and get things moving. I would like to have gone in and clipped the legs but it's too tight on the board.

                          So the crusher it was.
                          --
                          Wagdog
                          Check out Lunar Commander on:
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                          "Albert King could blow Eddie Van Halen away with his amp on stand-by"
                          - Joe Walsh


                          Good Transactions: Doctor Morbius(x2), Cadfael, bg-pups.com(x2), DCinDC, twotimingpete, dwerlin, DaleH, chqtarzan, sxyryan, lowbrow, albertus, vintage clubber

                          Comment


                          • #14
                            Also, how would it work out if I changed part of V2 similarly, for another "channel"(by crate's definition)? Would it be too quiet, would the tone stack not work out, or would it work?


                            Don't know and not really interested in trying. I like the amp the way it is right now (both of 'em actually, 'cept I'll probably change the speakers on the v18).
                            --
                            Wagdog
                            Check out Lunar Commander on:
                            iTunes App Store
                            Google Play

                            Lunar Commander Lite - FREE!:
                            iTunes App Store
                            Google Play

                            Free Fireworks Show for Android

                            "Albert King could blow Eddie Van Halen away with his amp on stand-by"
                            - Joe Walsh


                            Good Transactions: Doctor Morbius(x2), Cadfael, bg-pups.com(x2), DCinDC, twotimingpete, dwerlin, DaleH, chqtarzan, sxyryan, lowbrow, albertus, vintage clubber

                            Comment


                            • #15
                              Don't know and not really interested in trying. I like the amp the way it is right now (both of 'em actually, 'cept I'll probably change the speakers on the v18).


                              Well having a clean channel would be just great to have for me, I love the portability and power of the V18.

                              Comment



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