Moderators: pompeiisneaks, Colossal
I'll double check, but they should be right. I just swapped the 270's with 330 pf's on dogears' recomendation, so it's entirely possible that I didn't wire the new ones up correctly, but I'm fairly certain I did.Bob-I wrote:I don't see anything really wrong with your construction. It may be an optical illusion but the snubber look wrong. There should be 270pF caps from 1-3 and 6-8, they almost look like they're from 1-2 and 6-7. .
The caps are OD's. I believe they're 715's, but I'll check. Interesting that they sound brittle, if that's what they are. I'll check.Bob-I wrote: What caps and resistors did you use?
The resistors on the main board are all either carbon comp or carbon film. Not sure of the brand, though. These Visay Dale's, is it worth going through the exercise of removing all of the existing resistors and putting in Dale's? I can do that, but I wonder if it will be a lot of work with no audible result? I suppose it's hard to say until I do that, though...Bob-I wrote: I've found that some of the cheep metal film resistors really sound outright bad. I went to Vishay Dales on dogears' recomendation and the difference was amazing. Since then I've used some quality carbon films and they sound decent compared to the Vishay's but far better than the metal films.
Thanks for the tip. I ran into a problem in that the tube sockets I bought are oriented such that they had to go in this way. So what I tried to do was make sure the grid and plates didn't run prallel, but crossed at 90 deg where necessary. On the layout diagrams they're rotated 45 deg, I think, and it makes it easier to run the cathodes and plates parallel and right to the board. Question: can I do something about it as is? I mean, if I run a longer cathode wire from pin 3, I could route it around the right side of the socket so at least they'd be parallel untl they reach the board, then I'd have to snake the (black) cathode wire under the board behind the other wires and up to the cap and resistor where it's supposed to go. What do you think??Bob-I wrote: The lead dress that should be used on V2 is a bit against the rules. Take a look ath this thread and you'll see that the cathode and plate leads run parallel. Apparently Dumble used this for some reason unknown to us here, but it makes a difference.
You're right. I can separate these. I figured DC wouldn't have any effect on a signal. Is that not true? (this is all a grea learning experience!).Bob-I wrote: I also see a white lead from the master that seems to run parallel to the DC voltage for the relays. I may be wrong, it's hard to see, but if that's the case I'd move those leads apart.
markmalin wrote:It's a subtle difference, but noteworthy. Dogears is a big advocate of the 6PS. I've had good results from the Xicon MPP (little maroon chicklets)Bob-I wrote:The caps are OD's. I believe they're 715's, but I'll check. Interesting that they sound brittle, if that's what they are. I'll check.
No Just the 4 plate load resistors!!! Leave carbon film everywhere else. Very important, the metal films are bad as signal carrying resistors.These Visay Dale's, is it worth going through the exercise of removing all of the existing resistors and putting in Dale's?
Dunno. Try it and see what the results are.Thanks for the tip. I ran into a problem in that the tube sockets I bought are oriented such that they had to go in this way. So what I tried to do was make sure the grid and plates didn't run prallel, but crossed at 90 deg where necessary. On the layout diagrams they're rotated 45 deg, I think, and it makes it easier to run the cathodes and plates parallel and right to the board. Question: can I do something about it as is? I mean, if I run a longer cathode wire from pin 3, I could route it around the right side of the socket so at least they'd be parallel untl they reach the board, then I'd have to snake the (black) cathode wire under the board behind the other wires and up to the cap and resistor where it's supposed to go. What do you think??
Again, dunno but I've never seen a Dumble with these leads together. I bow to the master yoda.You're right. I can separate these. I figured DC wouldn't have any effect on a signal. Is that not true? (this is all a grea learning experience!).
I think so, but I'm a bit of a fanatic.Questions:
- is it worth buying all new PS caps?
Again, NO!!! Swap out the 4 plate load resistors on V1 and V2 only. The rest should be carbon comp.- is it worth swapping out all the resistors for Dale's?It's usually a subtle difference, but I've heard some dramatic differences too.- is it worth adding longer plate/cathode wires on V2 so I can
make them run parallel for a while??
It's getting hard to tell if the breakup is the amp or the recorder.markmalin wrote:OD trimmer at 12:00
Yes, that's where the input Vol. has been. Last night I tried odourboy's suggestion and turned it up past 1:00 and it does change the characteristics of the amp. Also, yes I did discover that with the OD trimmer down the sustain of the notes fades really fast, and when I turn it up it sustains longer (sometimes into feedback). This is good information for learning how to use this beast.Is the picture that shows the front panel indicative of where the input volume is? If so, try cranking that past noon to 1 o'clock or more like odourboy mentioned earlier in the thread. It sounds to me as if there is not much gain getting to the OD to get it crunching or singing. And I am also with Bob-I on cranking up the OD trim to get more happening there. Try just using your ears instead of an accepted norm - a trimmer or pot may be out of spec and just need to be cranked more than usual. FWIW, I never run my input volume at less than 1 o'clock and control the input volume at my guitar. IMHO a Les Paul should be taking an amp like this into singing solo voice territory rather readily.
This is good advice!! I have no "real" recording equipment - just thought the Sony would at least give me some way to let you guys evaluate it.I also believe your recording device might be clouding what we are hearing on our end. Compression and fidelity may be an issue with the recorder and mic. For reference you may want to record some well known material from your stereo with that device and let us hear it. Perhaps a CD of a well known player of Dumble amps taking a lead break.
This is the very thing that's troubling me. The "lifelessness". I hear other players' (yours in particular, to be honest) and that's not what my amp is doing. It's like the punch is getting squelched (squashed) and what results is a brittle, sharp attack follwed by a fastly fading note. I think I'll go for the new caps (it's only ~12 bucks and a week of waitingstelligan wrote: If what you are hearing in the room is lifeless, that is definately not where you want to be. I have never built one of these without 6PS caps or Vishay Dales at the plates. Sad but true - that may be a route to contemplate.
Dave
Do you have a Mouser part # for the Visay Dales? So we're talking just the 4 plate resistors on V1 and V2, right? (The ones the plate wires connect to.) I can do that.I'll give it a try up around 3:00. With the gain at 12:00, isn't it total "fuzz"? Like I mentioned to Stelligan, I am trying to get a Dumble overdrive vs sort of that Marshall fuzz tone. I'm going to take his suggestions and yours and do some messing around with the OD trimmer and volume settings. Also, I think I'll go for the differen caps and the plate resistors and breath a little more lead smokeBob-I wrote:It's getting hard to tell if the breakup is the amp or the recorder.markmalin wrote:OD trimmer at 12:00
It sounds like you're going for a light crunch, which honestly is better on the clean side, just turn UP!!. These amps like to sing. Bring that trimmer up to 3:00. Set the gain at 12:00 and the drive at 12:00. T=11:00 M=1:00 B= 1:00
What happens if the trimmer is too low is that OD1 doesn't quite overdrive, so all the OD comes from OD2. I've always found the best OD sound to come when both sides are fairly equal in the way they round the signal off.
JMO.
