I have a Snapmaker 3 in one system , with the cnc/laser/3d printer attachments , I use the 10w Laser module , works well for what I need

Hi Folks , Haven't been here for a while , an update on the Express build after 9 months, spent a bit of time going through it these last couple of days , been having issues with volume and bias (again) . found two problems that combined made it very frustrating to nut out . the volume was not as loud as you'd expect , I could play it with the volume at noon and it didn't tear your head off, It WAS running a set of Mullard reissue EL34's , Checked the bias - cold again - yet it hadn't been played for 4 months , rebiased to 70% and the volume came back nicely , played it for a bit and as the tubes heated up/settled the bias shifted again , from 44mA to over 55mA , reset again and now the volume had dropped back to before . As I had the screwdriver in the bias pot i watch the bias meter jumping all over the place ... aha ... dodgy bias pot , so I swapped it out for another pcb mounted pot (different brand) worked well for a while, then started doing the same thing .... frustrating , tried another but ended up removing the PCB mounted ones and put the old Fender CTS 10k pot on the chassis and ran some wires (needed to change the value of the 47k bias resistor to compensate for the pot now being 10k ) this seemed to fix it , biased the Mullards again and left the amp on for 4 hours to monitor it ... at 2 hours it was fine - 44mA but at 4 hours it went up to 55mA , then one tube was 55mA and the other was 0mA , then went back to both at 44mA . I wiggled the pot again and it was solid , no more jumping around ... I concluded the Mullards were unstable and would fluctuate up and down the longer they were on , (not good for gigging) , so I put a set of EH6CA7's I had in, reset the bias and the results are great, stable non fluctuating and the volume returned , I guess either the reissue Mullards don't like running at 70% for long periods, or they become unstable when running hot for long periods OR I got a bad set of tubes ... I'm liking the 6CA7's a lot, much more glassy , tighter bottom end and less compressed . It's personal choice I know , but so far I'm digging them ... Anyway I thought I'd share my latest findings , I've read many times on the net that the Mullard reissues are fantastic , They may be but my experience is different and I'm going with that - rock on everyone

Thanks Andrea , I was looking for the axials so I could put it on the board , the layout says 300uf and the schem says 220uf , I've ordered some 220 axials, regards

Hi Brains trust , quick question , I'm getting some harsh grainy sounds on selected notes on the guitar , mainly low E and A strings around the 5th fret ... at first I thought it may be in the speaker , but I changed it and it's still there . If I bias the amp to around 65% - 70% plate Diss then it's only occasionally that it occurs , but as the amp warms up it gets more frequent .... I've played with the lead dress, chopsticked the whole amp , it's doing my head in , As I'm not very familiar with the Express circuit in detail , I was hoping someone could point me in a direction to solve this. the GEOFX Debug site has this - Ugly sounding distortion can take several forms. Harsh grainy sound • Output tubes biased 'way too cold • Rubbing or torn speaker cone • Rarely, the amp can be oscillating ultrasonically and still get some sound through, with a harsh, ugly sound. Sound cuts out or squawks on loud notes • Failing coupling capacitor • Failing plate resistor, cathode bypass cap, cathode resistor or grid resistor • Intermittent ultrasonic oscillation Muffled or constricted sound • Failing preamp tube; find the offending section by tube swapping and see if a good tube fixes the problem • Low signal tube bias is pushing it into saturation or cutoff. Measure operating voltages on the preamp tubes. The problem section will have tube pin voltages that are 'way off normal. • Failing coupling capacitors from the preceeding stage. • Failing plate resistor, cathode bypass capacitor, cathode resistor, or grid resistor • Power supply problem; a dropping resistor may have drifted far from it's nominal value, changing the power supply voltage enough to cause this. I've tested all these possibilities , but to no avail , any advise would be appreciated regards Watto

very nice

very nice build , where do you get your relay switches from ? I'm looking for a good source regards Mark

Hi Rick, The enclosure is just a generic one , I bought it from MableAudio in China ... They sell all kinds of Amp hardware ... I think from memory it was this one http://www.mableaudio.com/en/productview.asp?sid=5046 The faceplate was designed by me , I have a Laser Etcher that I use the etch my faceplates , so I did a one off for this build regards Mark

yes it can, but it's a waste of the board , I followed the traces and it can be done ..... easier just to make a standard turret board FYI

All done , turned out great , I like the extra interaction it gives you with the ODS .. even without pedals plugged in

I'm halfway through my Express build, Chassis is almost complete , just need to hook up the front pots , It's in a custom Fender tweed style chassis , I'm building the combo cab at the moment , It'll be a 1 x 12 , and will run 6V6's (I already have an EL34 Head) It's a tight squeeze , But I'm sure it'll turn out fine ... I used a Hammond 290MAX P/T which gives me 280-0-280 and a reissue JTM 45 O/T that I had lying around , I know the imdecences aren't 100% correct but I'm hoping it'll be a nice outcome all the same .... pictures will come soon

All finished and in the rig , I have built an ODS #124 copy and it works great with that , very happy with the results , I'm building a wooden housing for it to match the amp ... then it'll match the rig

Congratulations , very nice build , I use to switch the neutral but not anymore , I just hardwire that and switch the active now, What ODS is yours based on ?

Thanks I just ordered one from Nik ... this'll be a fun project

Hi Caleyskinner, I'm in Australia and I'm building the Dumbleator , Does the Ceriatone PT require any mods to the PCB or is it a simple hookup as per the layout ? regards Mark