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Valve Senior is in the HOUSE!

#81 User is offline   brianh 

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Posted 14 January 2010 - 02:38 AM

Bump...:)
"Two things are infinite: the universe and human stupidity; and I'm not sure about the universe."
-- Albert Einstein
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#82 User is offline   J.Ventura 

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Posted 31 January 2010 - 10:54 AM

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.
Posted Image
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
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#83 User is offline   brianh 

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Posted 02 February 2010 - 08:00 AM

Nice!
"Two things are infinite: the universe and human stupidity; and I'm not sure about the universe."
-- Albert Einstein
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#84 User is offline   jaydodge 

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Posted 01 March 2010 - 04:51 PM

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 [biggrin]

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 :)
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#85 User is offline   J.Ventura 

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Posted 01 March 2010 - 09:02 PM

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.
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#86 User is offline   jaydodge 

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Posted 01 March 2010 - 11:41 PM

it might work..i might be imagining that tho [cool] 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 :)
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#87 User is offline   J.Ventura 

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Posted 02 March 2010 - 02:47 AM

Quote

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.
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#88 User is offline   jaydodge 

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Posted 13 March 2010 - 09:40 PM

I had a look at my dwell mod setup..here is what I have in there at the moment.

Posted Image

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..

Posted Image

cya
jay
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#89 User is offline   Svet 

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Posted 14 March 2010 - 12:42 AM

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!
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#90 User is offline   brianh 

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Posted 14 March 2010 - 01:37 AM

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
"Two things are infinite: the universe and human stupidity; and I'm not sure about the universe."
-- Albert Einstein
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#91 User is offline   Svet 

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Posted 14 March 2010 - 02:37 AM

LOL, thanks Brian, I am in the NE area per se but a little west in New York [blink] thanks though
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#92 User is offline   bremzzi 

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Posted 05 April 2010 - 02:37 AM

hey jay, how does that reverb mod sound, have you modded your amp yet or is that just an idea? cheers
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#93 User is offline   jaydodge 

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Posted 06 April 2010 - 10:29 AM

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 :-k

I will send through a photo later [thumbup]

jay
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#94 User is offline   daddy-o 

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Posted 10 June 2010 - 01:07 AM

Hi Jaydodge, any chance to take a picture of the rev mod yet?

Many thanks!
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#95 User is offline   jaydodge 

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Posted 13 June 2010 - 05:27 PM

here are some pics..
http://img88.imagesh...modfullcov.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.images...dwellcontro.jpg

cya
jay
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#96 User is offline   daddy-o 

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Posted 16 June 2010 - 03:38 AM

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.thegearpa...t=568396&page=3

But then I read:

Quote

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?
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#97 User is offline   jaydodge 

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Posted 18 August 2010 - 05:08 PM

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
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#98 User is offline   hooch1 

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Posted 02 September 2010 - 09:41 AM

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?
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#99 User is offline   A Strummer 

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Posted 19 March 2011 - 11:00 AM

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.
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#100 User is offline   ozigor 

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Posted 20 March 2011 - 01:43 PM

Brian
Can't get the videos working
Can you post a link please?
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