This one has a pretty interesting backstory. It is supposed to be be based or simulate the tube section of Filmosound projector from the 1950s. After listening t o the demos it seems to be a Tweed style overdrive.
Schematic is avaiable HERE.
This one has a pretty interesting backstory. It is supposed to be be based or simulate the tube section of Filmosound projector from the 1950s. After listening t o the demos it seems to be a Tweed style overdrive.
Schematic is avaiable HERE.
Input is below Gain 2?
ReplyDeleteYup
DeleteNot really close to a tweed amp.
ReplyDeleteNo power flow. All I found so far is Treble 1 and 2 and Bass 1 and 2 should be swapped.
ReplyDeleteI couldn't get the Julia going either. I couldn't find anything obviously wrong with either of them but nada. Thanks for nothing Walrus Audio! Just kittens.
ReplyDeleteGot it. Verified. Fried my diodes somehow. Swapped them and cleaned the joints with alcohol and it came on. It sounds pretty cool. It is somewhat tweedy. I think most amps were at that time. Very nice and punchy fuzzy drive. Sorry Walrus and thank you Anders.
DeleteThanks Tom.
DeleteTagged.
Just finished this and it sounds great, but there's something bugging me. Nothing sound related. More for my own educational benefit. I'm getting 4.5v on the drains of Q1 and Q2. Q3 is 16v drain and 4.5v gate. Q4 is the one that's baffling me. The trimmer for Q4 seems to make no difference to the drain, which remains at 16v, but seems to act more like a volume control. Presumably this is normal because the pedal sounds great and pretty much like all the demos, I just feel like I'm not understanding something here, if you get what I mean?
ReplyDeleteThis comment has been removed by the author.
DeleteI found a conversation online stating that Q1, Q2 and Q4 should all be biased around 8.3v each. I don't like it as much now though haha. I'll have to tinker with the bias by ear. But that is where the FETs should be biased ideally according to WA. Makes sense. I hadn't considered the 1044's overall voltage increase.
DeleteCool thanks for that. I think I’m in agreement with you though. It sounds so good the way it is I think I’m going to leave it 😆.
DeleteYup, I had the same readings. It sounded so good I didn't question it. It is odd. I'd like to know what the reason is too.
ReplyDeleteHey, J4, is that meant to be 100n film capacitor like the others (o15, c13)? The symbol has me thrown
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DeleteIt's meant to be 100nf ceramic. But a 100nf film would work fine too, in my experience.
DeleteThanks for the help. Built two of these but only had enough j201s for the first. Decided to experiment with 5457s for the 2nd and whilst the sound is great, the volume is much lower. Any suggestions for component changes to raise the overall volume? I will be grabbing more 201s but figured I might as well see how well I can get it working with these for now
ReplyDeleteYeah, it's a cool one. It has a unique sound. JFETs are often temperamental. Personally, I'd hold out for some different parts rather than change the circuit. If you have any other FETs, try those.
DeleteI just built this and it’s an awesome pedal. I used smd j201s, so I had fun making legs out of old resistor clippings. I own a 385 amp that I restored and this pedal does give the feel of a tube amp like a Filmosound with very natural gain. You can get a fairly clean to very dirty sound with this circuit , but I like it at the setting right before it starts breaking up. Thank you Anders!
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ReplyDeleteGot to this one a little late, but I really dig it. Like Tom said above, gotta swap the wiring for treble 1 & 2 and also bass 1 & 2.
ReplyDeletebut I also noticed that left the sweep of the bass knob reversed (less bass when dimed). fwiw, Anders' layout is correct per the schematic, I think the bass pot on the schematic was mislabeled.
The order I wired it is (from top to bottom):
bass 2
treble 2
treble 1
bass 3
bass 1
treble 3
everything seems to be working as expected now.
Brain is right. Wiring was wonky. I just wired this up tonight and then saw this update. It all went so smoothly too. Haha. Anyway, As I see it it works as follows (again, from top to bottom)
DeleteBass 2
Treble 2
Treble 1
Bass 1
Bass 3
Treble 3
Just boxed this circuit up recently. There's something a little special about this one. Not totally dissimilar to the 1484 preamp but more compressed and pleasant sounding to my ears. And optimal bias is in fact basically optimal. Thanks for catching the wiring errors brain.
ReplyDelete