Ok so I reversed all the knobs and they work correctly
The amp sounds amazing!!!!!!!!!!!!!
a few how do you work a dumble questions?
1) I notice sometimes if the preamp gain is up to around 4 and you kick in
the OD the sound volume drops even with the ratio turned all the way up unless you also keep the level high as well. In other words, If I keep the level in the mild OD fuzz around 3 and have the ratio all the way it is still lower volume than the regular channel. If I set the regular channel gain to low levels than all is ok?
2) It seems all the tone controls are so much more subtle than a conventional amp? Is this because Dumble doesn't want you messing with his tone? Also the bright switch is amazingly subtle is this how it is supposed to be?
3) wow its loud!!!
Thanks everyone for so much help, my friend and I have been playing it for 4 hours straight.
Dumble's ODS amps are designed with what is called a "cascaded" architecture. That means that the signal "falls" if you will, from one section to the other.
In order for the OD section to "sound" or operate properly you should have a relatively strong signal coming from your "clean" part of the amp in order to drive the OD section that follows it. It is a known issue that the amp has a volume imbalance between the clean and the OD. There are a few posts on how to remove (via circuit mods) as much imbalance as possible, use the forum's search function. Meanwhile, learn how to master these volume differences and bring them under control by adjusting the input volume of the clean and the output of the OD together with the master volume, you will most likely find a decent result.
Yes, the tone controls are subtle compared to a Fender or a Marshall.
One last thing, this is no plug and play amp, it takes time to understand, control and master it's great qualities. You change from single coils to humbuckers and you're back to adjusting again.
Exactly as Horacio says on the imbalance, but I would add that to be dynamic with a clean sound it needs to be tremendously loud compared the dirty anyhow. The best way is to get it very close and relax your style around the clean settings. If you can find a vid of Eric Johnson playing and imagine that the Twins are RAGING against the Marshalls, just not played that way.. same thing.
Happy for you and jealous that I don't have a new amp to tweak.. for a minute at least.
Way ta go!
Signatures have a 255 character limit that I could abuse, but I am not Cecil B. DeMille.
Since you have successfully constructed a sounding, non-smoking amplifier on a hay stack, I can only say: CONGRATULATIONS!
I if I had built it with your lead dress technique I am certain it wouldn't work.
I am going to give you just a couple of recommendations:
If you ever start to hear the amp sounding kind of weird, do yourself a favor and look at other pictures of tidy ODSs around here and do copy them as you see them, for most likely, either soon or later, that lead dress is going to give trouble, that is almost a guarantee.
This second recommendation is given for safety reasons. Your rectifier/bias board (photo4.jpg) is about to come loose, you have got close to or over 500 volts there. I recommend you get longer screws, use safety washers and install the nuts (plural). All that before you fire it up again! Safety first !!!!!!
I just saw this: On that same board, the two red wires that come from the transformer; are they soldered from the back? if so, I recommend you solder them from the front of the board, they are your hight voltage taps and you should place them were you can easily inspect them. If one of those wires brakes away from the eyelet and touches the chassis, you could become a candidate to get listed on the obituaries of your local paper.
A car is a great machine, if operated properly it is a very useful tool. If operated inappropriately, it can become a killing device.
A guitar amp is a very enjoyable device, if constructed properly. It can and it will kill you if it's not.
Thank yourself for posting those photos and do take time to properly redo your lead dress, there are many other Dumble models around and I personally want you to build and enjoy them all. So, be careful!
echo44 , with all my respect , your lead dress is rather poor , how can you think that works.
I suggest you to re-wired the amp! and pay attention to the lead dress.
Lead dress is one of the thing very important in Dumble amps and can compromise the tone also!
