Dino_K Posted December 25, 2009 Share Posted December 25, 2009 MERRY CHRISTMAS Just unwrapped the Valve Senior Combo that Santa brung me, and have already been playing with the various settings. All I can say is WOW!!!! This thing sounds great. The suggested settings are pretty good, although with a little tweaking they can be truly outstanding. Lots of dynamic range and touch sensitivity here, highly adjustable gain, plenty of volume and a TON of great sounds inside this box. I have found a few downsides, some serious and some purely design issues: (1) It has as much reverb as my 5E3, which is to say it is non-existant. Any word from Epiphone on recommended improvements? I had a Mesa Mark IIb with this issue and even the folks at Mesa said that was just the way it was. (2) When I went to check the reverb tube (hey, maybe it was dead already) I discovered that the back panel was on so tight I literally could not get it open. Eventually, I was able to get the back panel off (hey it is a very good fit, if a wee bit tighter than I expected!) and I discovered that, (3) While the power tubes are chassis mounted, the 12AX7's are mounted direct to the PCB. As it ages, the heat and vibration are likely to age it prematurely (4) It was actually bigger and heavier than I expected. Not Fender Twin heavy, but I seemed to think it would be about 16"x16" and weigh about 30 lbs. It's acually 18"x18" and weighs about 40. Not a huge difference, but I was a bit surprised when I pulled it out of the box. All in all, it is definitely a keeper, especially for the price! Quote Link to comment Share on other sites More sharing options...
brianh Posted December 26, 2009 Author Share Posted December 26, 2009 Congrats Dino, I'm keeping mine too. 1) I'm still hoping that someone at the Sewatt site will come up with a mod to the reverb circuit, it doesn't appear to be a problem with the tank itself. 2) Back panels are put on while the tolex glue is still drying, so it tends to weep out and glue the panel to the enclosure. Same problem on the other two Epi valve amps I've had. 3) Probably correct. These amps are not really intended as hard core touring amps. 4) Mostly the weight of the MDF enclosure. Cheers, and enjoy... Quote Link to comment Share on other sites More sharing options...
Tragic1281734187 Posted December 29, 2009 Share Posted December 29, 2009 I have replaced the reverb tank with a Accutronics. I do not hear any change. There must be a way to add a mini pot to control the dwell. ? Quote Link to comment Share on other sites More sharing options...
brianh Posted December 29, 2009 Author Share Posted December 29, 2009 Yep, it's not the tank as I figured. Post it on www.sewatt.com and see if anyone there has any ideas. Let us know what you find out, we'd all benefit. Thanks, Brian Quote Link to comment Share on other sites More sharing options...
J.Ventura Posted December 31, 2009 Share Posted December 31, 2009 Try this: increase R32 from 100K to 330K. Happy new year. Quote Link to comment Share on other sites More sharing options...
brianh Posted January 14, 2010 Author Share Posted January 14, 2010 Bump...:) Quote Link to comment Share on other sites More sharing options...
J.Ventura Posted January 31, 2010 Share Posted January 31, 2010 Hello. I've updated the schematic to adjust the values of C6/7 (150p) and C25 (22u). I checked the other components and are all ok. Here's the schematic and component list checked one by one. RESISTORS R1 1M 1/2W R2 330K 1/2W R3 68K 1/2W R4 1K5 1/2W R5 56K 1/2W R6 4K7 1/2W R7 470K 1/2W R8 3M 1/2W R9 1M 1/2W R10 1M 1/2W R11 1K2 1/2W R12 33K 1/2W R13 1K 5W R14 10K 2W R15 68K 1/2W R16 4K7 1/2W R17 91K 1/2W R18 100K 1/2W R19 1K 1/2W R20 1K 1/2W R21 1K 2W R22 250O 10W R23 1K 2W R24 1M 1/2W R25 1K5 1/2W R26 1M 1/2W R27 1K5 1/2W R28 330K 1/2W R29 10K 2W R30 470K 2W R31 470K 1/2W R32 100K 1/2W CAPACITORS C1 C2 22n 400v C3 C4 22n 400v C5 C10 10n 400v C6 C7 150p lentil C11 C12 250p 500v C13 C14 22n 400v C15 C16 100n 400v C17 C18 100n 400v C19 C20 100n 400v C21 C22 100n 400v C23 C24 47p 500v C27 C28 250p 500v C30 C31 1n 400v C35 C38 22n 400v C39 ¿? 47n (what is it doing here?) C40 C41 1n 400v ELECTROLYTICS C8 +/- 22u 50v C9 +/- 22u 50v C25 +/- 22u 50v C26 +/- 6u8 50v C29 +/- 6u8 50v C32 +/- 22u 450v C33 +/- 22u 450v C34 +/- 22u 450v C36 +/- 22u 450v C37 +/- 22u 450v POTENTIOMETERS Gain 1M log Treble 1M lin Middle 25K lin Bass 1M log Presence 25K lin Master 500K log (double) Reverb 1M log Quote Link to comment Share on other sites More sharing options...
brianh Posted February 2, 2010 Author Share Posted February 2, 2010 Nice! Quote Link to comment Share on other sites More sharing options...
jaydodge Posted March 1, 2010 Share Posted March 1, 2010 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 :) Quote Link to comment Share on other sites More sharing options...
J.Ventura Posted March 2, 2010 Share Posted March 2, 2010 So it seems there are two versions. I'm sure my values are correct too. Specially C25, I know it well because it exploded two times because a deffective tube. The idea about the dwell control looks interesting. I played with R31 value (put a 4M7 pot in parallel) and it did nothing, but now I guess changing both resistors for a pot as you suggest should work... My 4 last digits: 0059. Quote Link to comment Share on other sites More sharing options...
jaydodge Posted March 2, 2010 Share Posted March 2, 2010 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 :) Quote Link to comment Share on other sites More sharing options...
J.Ventura Posted March 2, 2010 Share Posted March 2, 2010 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 :) Well, I hope my new tubes are good and this never happens again. ;) Maybe I try it one of these days. Quote Link to comment Share on other sites More sharing options...
jaydodge Posted March 14, 2010 Share Posted March 14, 2010 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 Quote Link to comment Share on other sites More sharing options...
Svet Posted March 14, 2010 Share Posted March 14, 2010 Hi Brian, I just saw your videos here and I must say that I am very impressed! Your demonstration of the VS is far and away more professionally executed than most of the other attempts I've seen. Kudos! Quote Link to comment Share on other sites More sharing options...
brianh Posted March 14, 2010 Author Share Posted March 14, 2010 Thanks Svet, I've been meaning to add a couple more demos with the LP '57 Jr. RI and the cigar box guitar. Might also help if I warmed up a little. Maybe I'll do it today, the wife's going out for a while... PS, you live in New England area, right? There's a VINTAGE '66 tea burst Casino at the Natick, MA Guitar Center. Single P90, but it sure looks nice. Item no. 103383147, on sale for $1,995. Seems like a good price... And to anyone in the NC area, there's a JL Revolution Casino at the Durham GC for $1,500, item no. 105077594. Cheers, Brian Quote Link to comment Share on other sites More sharing options...
Svet Posted March 14, 2010 Share Posted March 14, 2010 LOL, thanks Brian, I am in the NE area per se but a little west in New York thanks though Quote Link to comment Share on other sites More sharing options...
bremzzi Posted April 5, 2010 Share Posted April 5, 2010 hey jay, how does that reverb mod sound, have you modded your amp yet or is that just an idea? cheers Quote Link to comment Share on other sites More sharing options...
jaydodge Posted April 6, 2010 Share Posted April 6, 2010 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 Quote Link to comment Share on other sites More sharing options...
daddy-o Posted June 10, 2010 Share Posted June 10, 2010 Hi Jaydodge, any chance to take a picture of the rev mod yet? Many thanks! Quote Link to comment Share on other sites More sharing options...
jaydodge Posted June 13, 2010 Share Posted June 13, 2010 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 Quote Link to comment Share on other sites More sharing options...
daddy-o Posted June 16, 2010 Share Posted June 16, 2010 Jaydodgce many thanks for the piccs! They are extremely useful but I don't have the expertise and the tools for that... I think it will cost me less to buy an Accutronics unit than having a tech do the Dwell mod. Somebody has succesfully replaced the original Ruby rev tank with an Accutronics R8DB2C1C: http://www.thegearpage.net/board/showthread.php?t=568396&page=3 But then I read: I have replaced the reverb tank with a Accutronics. I do not hear any change. There must be a way to add a mini pot to control the dwell. ? Tragic, can you tell us the exact Accutronics model you tried? Quote Link to comment Share on other sites More sharing options...
jaydodge Posted August 18, 2010 Share Posted August 18, 2010 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 Quote Link to comment Share on other sites More sharing options...
hooch1 Posted September 2, 2010 Share Posted September 2, 2010 I just ordered the combo. So from what I have read on this thread, it sounds like the reverb tank is just fine as is and there needs to be an actual circuit mod to fix the issue? Quote Link to comment Share on other sites More sharing options...
A Strummer Posted March 19, 2011 Share Posted March 19, 2011 Noob question for jdodge: I noticed in your pics that you re-capped your with Orange drops. I want to do the same on mine. Did you change any of the cap values, or was it a straight swap? Also, what are those little black caps in your pic? Thanks. Quote Link to comment Share on other sites More sharing options...
ozigor Posted March 20, 2011 Share Posted March 20, 2011 Brian Can't get the videos working Can you post a link please? Quote Link to comment Share on other sites More sharing options...
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