DuoCast vs a real Broadcast

caiofilipini

Well-known member
A while back I built a DuoCast that didn't sound at all close to the Broadcast demos I'd seen. I tried a whole bunch of different germanium transistors, and they made some difference, but overall the pedal was lacking something.

So I bit the bullet and got myself a real Hudson Broadcast Dual. What a sound!

Anyway, I found and fixed an issue with my build (more on that here), so I decided to do a quick shootout against the Hudson:


You'll find this in the video description too, but my initial impressions are that the overall sonic characteristics are all there, even though there are some noticeable gain differences between the two, which likely boils down to the specs of each transistor.

Overall, I think the DuoCast sounds pretty cool!

Hope this is helpful.
 
Jealous. I really want to pick up a real one, but I’m afraid it might taint my perfect sound from the one I built. Lol. Awesome side by side.
 
I didn't think they sounded that different in your video. At least I couldn't tell while it was playing on my phone while I'm cooking breakfast!

Yeah, I tried to dial them in the same ballpark, I guess the main difference is when you try to position the knobs the same in both pedals. Mine seems to have more gain and more volume in the low channel, but less volume in the high channel.

I should also say I set the internal trimmers the same in both. Could probably get them to sound even closer by fine tubing the trimmers to compensate for the differences.
 
I listened again with headphones and I could hear the gain difference but the overall character of the two was the same. Sorry if you explained this elsewhere but did you try swapping different ge transistors to see if you could get yours closer to the Hudson?
 
Thanks for sharing the video! There is definitely a difference in the gain structure. The Broadcast seems to have more bite to it, if that makes any sense.
 
Yeah, I tried to dial them in the same ballpark, I guess the main difference is when you try to position the knobs the same in both pedals. Mine seems to have more gain and more volume in the low channel, but less volume in the high channel.

I should also say I set the internal trimmers the same in both. Could probably get them to sound even closer by fine tubing the trimmers to compensate for the differences.
I'd almost bet the differences are in the biasing (with a bit of wiggle room for minor component variants).
Also, the pots could be a good bit apart on values even at the same rotation.
 
I agree you shouldn’t rely on the pot position. The tolerance can make two pots with identical specs quite difference. Same goes for trimmers. Using your ears is probably the best way to go.
 
I'd almost bet the differences are in the biasing (with a bit of wiggle room for minor component variants).
Also, the pots could be a good bit apart on values even at the same rotation.

Biasing is not that far off, actually, so I really think it's a combination of hFE differences and component tolerances, especially with the pots.
 
I listened again with headphones and I could hear the gain difference but the overall character of the two was the same. Sorry if you explained this elsewhere but did you try swapping different ge transistors to see if you could get yours closer to the Hudson?

I did test a bunch of them when I first built it, but since my BC549C was installed backwards, I'm gonna have to do that again. I tried a couple yesterday, but will try some more when I get a chance.
 
By the way, for those of you who are curious, my Broadcast has an NTE 2N404A in Q2. It is socketed, but I believe it's been soldered to the socket, because I couldn't pull it out.
 
I did test a bunch of them when I first built it, but since my BC549C was installed backwards, I'm gonna have to do that again. I tried a couple yesterday, but will try some more when I get a chance.
Right, that was the one you got from PedalHacker. That was curious to me. If you find out anymore info, plz share.
 
Right, that was the one you got from PedalHacker. That was curious to me. If you find out anymore info, plz share.

Yeah. I can't find a datasheet for Ferranti specifically, but I did notice it's marked BC549CP, so maybe that has something to do with it?
Anyway, I feel like I should get some regular BC549C to test in there as well.
 
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Yeah. I can't find a datasheet for Ferranti specifically, but I did notice it's marked BC549CP, so maybe that has something to do with it?
Anyway, I feel like I should get some regular BC549C to test in there as well.
I'm pretty sure the pinout is still CBE, but I am far from an EE...so grain of salt.
 
By the way, for those of you who are curious, my Broadcast has an NTE 2N404A in Q2. It is socketed, but I believe it's been soldered to the socket, because I couldn't pull it out.
I think I prefer the NTE 2N404A. The GT sounds more spit-ty. Now to track some of these down. Thanks a lot. 😉
 
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