July 26, 2012 NOTE: With the number of posts in this thread reaching 812 eeks) I thought I better add some notes to the initial post here. There have been a lot of really good suggestions and fine-tuning tweaks on how to improve the Soldano mod scattered throughout all 55 pages and I plan to consolidate them all (with the generous help of some of the contributors- a big thanks to all of you!) If you are planning to do the Soldano mod before I get that written up let me know (post, PM or email) so that I can pass on some of those suggestions. I came up with the basic architecture of the mod and plugged in the basic values from the SLO schematic without doing a whole lot of fine-tuning. Some of the people here who tried out those basic values did more experimenting than me and have posted their recommendations here. Scattered among the 55 pages of posts... I have 3 of the V18-112 amps (5 as of 01-15-09) that I'm screwing around with. I'm finishing up the fine-tuning tweaks on the first one, which started out with the conversion to the Clean Channel of the V33. By "conversion" I mean reconfiguring the basic architecture of the amp rather than just replacing individual components or adding specific features (which I would consider to be "mods"). The main change was eliminating the second stage by pulling resistors and capacitors, and adding jumpers as needed. I'll post the full details of that conversion as soon as I finish it up. For now I thought I'd post something I drew up the other night- a completely untested conversion of the preamp to the specs of the Soldano SLO OD channel. (There are so many similarities in the architectures of the two amps that I wonder if it is more than a coincidence... ) It will presumably need some fine-tuning tweaks since the SLO is a high gain circuit susceptible to feedback, etc. So without further ado... Converting a Crate V18 to the OD channel of a Soldano SLO: R1 220k R2 1k8 C6 1uF C1 .02uF R6 remove C2 jumper C3 .002uF CW1 500kA* [EDIT I reverted to stock 250kA pot] R4 remove R65 470k C10 remove R3 100k R11 stock 100k but bypass it with 0.001uF cap R5 1k8 plus 1uF cap R61 470k R13 39k R16 1k8 C13 1uF R15 use 100k (stock) up to 150k R18 47k R22/C16 jumper out [EDIT I removed jumper] (CW2 1M A) optional [EDIT I reverted to stock 250kA pot] The following are optional: R43 & R44 2k2 R45 & R46 220k (reroute leads per layout drawing) add 120pF "snubber" cap between two terminals on C21 and C22 coupling caps that are closest to the top panel controls (this can help control any unwanted oscillations- add it if necessary) * The regular SLO uses a 0.001uF bright cap across the pre gain volume pot but it is removed for the Warren Haynes mod. You might want to wire this up to a switch. Steve Ahola P.S. There are many errors in the factory schematics for the Crate V18 so be sure to download the corrected ones from my site: http://www.blueguitar.org/new/schem/misc_amp/crate_v18_corrected_drawings_v2.pdf Enjoy!