jaydodge

quick update..found some spare time to mod this again so i decided to add a triode mode switch on the back to reduce the output power from 20watts to something more bedroom friendly..definitely did the trick - plus it adds a bit more tonal variety. it involves removing R21/R23, adding them to the bottom of a DPDT switch, joining them and running a single wire back to the B+ line for grid 2..with the two middle pins on the switch, you connect up wires back to where R21/R23 were (so one wire from pin 4 of each output tube)..then the top of the switch has a couple of 100ohm fusibles for protection with wires going back to the pin 3 of each output, making sure you follow the same pattern you used for the wiring of each pin 4.. very happy with the result.. :) jay

here are some pics.. http://img88.imageshack.us/g/jaydodgedwellmodfullcov.jpg/ when i am listening to this amp and not looking at it, it's fantastic..pitty about it being so bloody ugly haha...coz damn it sounds great..i am in two minds about keeping it given the number of amps i have..i can't keep all of them and it is damn ugly...the only reason it is still here is because it sounds amazing..but i only have room for so many....the dilemma! oh..and from the outside, it looks like this... http://img252.imageshack.us/img252/1872/jaydodgebackdwellcontro.jpg cya jay

Hi bremzzi, yes this is what i have in my amp except I changed R31 from 1M to 2M. I have R31 and R24 removed from the board and connected directly to the pot at the back of the amp (next to the speaker outs). So yes, sounds good and not just an idea I will send through a photo later jay

I had a look at my dwell mod setup..here is what I have in there at the moment. I would be interested to know if anyone else has tried something similar. Also..I cleaned up the schematic a little more - added voltages etc.. cya jay

it might work..i might be imagining that tho could be something around there ;) next time it blows you could try a 1u cap then and see what happens..i might try a 22u and see :)

Hi J Ventura I doubled checked my board and C25 is definitely 1uF/50V (branded Imagine like the rest) on my revision..so they might have changed that already?? - the last 4 digits of my serial are 0010. I will have to remove the board to check what value was in C6/7 - but could be a similar revision..it wouldn't make a huge difference - you can graph the difference in that tone stack program.. Thanks for checking it out Re dwell control - it probably slots in where R31/R24 are. You could remove R24, then disconnect the end of R31 from pin 2 of the tube, then connect pin 3 of your 1M pot to R31, pot pin 2 to tube pin 2 and pot pin 3 to ground where R24 was..least i think that was it from memory :)..better go and check that too :)

i misread some of the resistor values and messed up some of the layout in the power supply..so i have updated the schematic again!! :) EDIT - moved presence knob, tried to clean it up a bit more..i'll do the voltages later. cheers, jay

the solder is that high temp crap that requires you to add lots of normal solder to get the stupid stuff to flow properly...yes i am bitter lol a few of the connectors have broken off whilst i've been working on it..putting it in and out of the chassis.. i'd at least check those closely.

Well...a bit of sleep definitely helps..I found some mistakes in the phase splitter part of the draft schematic...and power supply..and..? Re Reverb - you can do a lot just by changing the resistance over the reverb pot..but yeah, the tank does kinda blow anyway..here is a link to the updated schematic.. which hopefully makes a bit more sense.. :) cya -jd

hi i got this amp about a month ago..here is a rough schematic.. and here is the board..along with cap values and wiring.. http://www.filesend.net/download.php?f=27cbb28160bc4e68aead1ea3dd315834 have fun... jay