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but aren’t the caps in parallel
in this case ?
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04-15-2024 12:46 PM
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TBH, I'm not really sure. There are multiple ways of wiring a tone control. It's late, and I've had an adult beverage or two, so I'm not going to try to do the work on it right now.
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Both have one leg on signal an the other on ground, so: parallel. One of them (the tone ctrl) in series with a resistor and (both) in parallel with the inductance of the pu coil.
Originally Posted by pingu
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I have the joyo American and on battery it is reasonably quiet. However, when I use it with an ac adapter, it produces a loud hum.
The same adapter works fine with other pedals. It is the correct 9v adapter with the correct polarity.
Does anyone have the same experience? Is my pedal defective?
-Charley
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I doubt the pedal is defective. It's likely the power supply is defective. Some switching power supplies are very noisy. I have several that are unusable with any pedal, although some pedals are less sensitive to the noise than others.
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Thanks. The power supply in question is quiet with other pedals. Can you recommend one you have used that is quiet with the Joyo? Originally Posted by sgosnell
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According to Chatgpt, if you put two caps in parallel the total capacitance is the sum of the two.
So, if you have a 20,000pf typical tone control cap in parallel with the 300pf capacitance of typical cable, the total is 20300. I think that means that if you dial the tone pot all the way down and it's wired to connect the cap to ground with no resistance in series, then you won't hear the capacitance of the cable.
OTOH, if you take the tone cap out of the circuit entirely, you would still have 300pf left from the cable. But what you're actually doing is putting a big resistance in series with it. This may have the same audible impact as removing the tone cap.
I wouldn't bet the farm that I'm right about this, but it seems to me that if you're already rolling off the tone cap part way, the capacitance of the cable probably won't be audible at all. The only difference is that the tone control might be rotated slightly to get the total capacitance where the player wants to hear it.
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I don't even know the brands of the ones I have. They came with various devices over the years, I've never bought one just for use with pedals. One that seems to work well is actually a transformer, that plugs into a 5VDC power adapter and boosts the voltage to 9VDC. It's among the quietest I've found, and I have dozens of 5VDC chargers acquired over the years, included with all sorts of devices - phones, tablets, etc. I sometimes use it with 5VDC power banks (batteries), and those work well, and are silent. If I have to use an actual 9VDC adapter, I just go through the bag and try some. Some (most) are noisy, but I'm too lazy to mark them.
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Calculating the capacitance of an RC circuit (which has both capacitors and resistors) makes my head hurt. But I'm not sure the total capacitance at the output jack, which is what counts, is the same as the tone capacitor, especially with two pickups. In any case, picofarads aren't large units. One trillionth of a farad. Originally Posted by rpjazzguitar
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Had this problem with Voodoo power supplies. If you do a web search you'll find it's a common problem. Originally Posted by charleyrich99
For a fix you can use a power supply that keeps the AC away from the board by using a power supply with an external transformer (wall wart) like MXR. Both of their models are compact and support quite a few high current pedals. I use them when I want a really light and small power supply. And while wall warts suck, they do keep noise away from your board. Then there is the Strymon Zuma which plugs directly into AC. Completely quiet with every pedal I've ever had close to it. Very nicely crafted. And kind of expensive for a power supply. Though honestly, it should last several decades so not sure how to equate value relative to the alternatives.
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I have a 12vdc Peavey battery amp that runs on 8 x 1.5v D cells. It also has a 12vdc power socket.. I'm in the UK and have tried 2 new (different brands) wall warts - 240vac to 12vdc 2A. Originally Posted by Spook410
Both are quite noisy. One was listed as a specific replacement unit for the amp (but not Peavey branded).
Any suggestions please? I don't have any other 12vdc equipment that I can test them on. Thanks
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Wish I could be more help. Assuming the way you stated this that the amp is quiet with batteries, noisy with wall warts. Really don't know but under the heading of 'any suggestions'.. Originally Posted by garybaldy
Since the transformer is away from the amp, it's not going to be poor shielding. Not a ground loop as there is no third wire. Since both wall warts are noisy seems less likely it's the wall wart. Though some lesser chance it still could be. That leaves power input circuit on the amp or the source of AC you're plugging into. If the amp is quiet with the wall warts when plugged into a source of cleaner power like an inverter or when plugged in at another locale, then I would say it's your AC power. Though, it's possible the transformer in a wall wart filters AC power noise. Or not. Don't know. Maybe do a web search on that one. If it's noisy no matter where you plug in, probably at the amp.
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Thanks. The amp is fine with batteries. When I can, I'd rather use a power supply but it's very frustrating. The problem is both at my home and where I rehearse. I guess, as you suggest, it's the amp. I'll take it to the guy that sorted a few dry joints in it when I first got it. Originally Posted by Spook410
Ofcourse I could try one more wall wart!!
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For batteries, I use rechargeable lithiums. The only use I have for regular alkaline 9V batteries is in smoke detectors. I also prefer using AC adapters, for convenience and economy, but it's hard to find a quiet one. As I said above, what I generally use is the converter cable that connects to standard 5VDC chargers. It's the quietest I've found. Something like this, although not that exact one. Mine is center positive, and I use a reversing cable that I made up to change it to center negative for use with pedals.
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I'm awfully slow on the uptake. I've finally twigged as to why my once super clean Musicman 65RP seems to breakup with my regular setting that I've used for many years. Thought it was due to the recent repair and revalving but may be not. Think I'll have to try the lo gain input next gig. Originally Posted by sgosnell
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I think the noise issue is with the pedal and not with the power supply. I even bought a second American sound because mine made ugly noises with the power supply.
I think after I bought the second one, the first one stopped making those noises. Anyway, I haven’t used both of them in a long time so I can’t really remember the details.
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You are correct. If the tone pot on typical magnetic pickup equipped guitar is rolled all the way back, the tone cap will be in parallel with the much smaller cable capacitance, so cable capacitance should have a negligible effect. I doubt many guitarists roll the tone pot back quite that far, but maybe a few in the jazz community do. Originally Posted by pingu
I generally roll the volume pot back more than the tone pot, so I’d be more interested in whether cable capacitance has an audible effect when the tone pot is set to around 7 or 8. That’s a lot more complicated to determine, since it depends on the characteristics of the pickup. It’s not something I think much about though, since I can usually dial in a tone I like with any good quality cable.
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I just did a quick test with my Joyo American Sound pedal into a solid state amp using a 1Spot power supply. I was using a single coil (non-humbucking) pickup and I was near some LED lights on a dimmer switch. There was very little hum (60 Hz or 120 Hz) or LED/dimmer buzz, and virtually no change running off the battery vs the 1Spot. Originally Posted by charleyrich99
I don’t have enough info to diagnose your issue, but I’d suspect either a poorly filtered power supply or a bad ground somewhere. Is what you hear a low frequency hum, or is it the high frequency buzz one often gets from LEDs, dimmers, video monitors, computers, and poorly filtered wall warts?
I’ve had the Joyo for a few years, but didn’t use it much until a few months ago. Now I use it most of the time. I start with the level near max, the drive near min, and all EQ controls flat, then tweak things a bit depending on the room, what instruments are in the band, etc. Small adjustments to the the Voice and Drive pots make it easy to dial in something pleasing. I wish I had something like that long ago. The Voice circuit is basically a mids control ahead of the clipping circuit. It’s nearly the functional equivalent of the Tech21 Blonde, though not a detailed copy of the circuit.
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I don’t understand what you’re describing. There is no such thing as a DC transformer. Transformers work because AC in the primary winding induces AC in the secondary winding, with the ratio of turns between them determining the ratio of output to input voltage. Originally Posted by sgosnell
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https://www.amazon.com/current-Negative-Connector-compatible-effects/dp/B07GD54Q66
The link didn't get included in the previous post, my fault I suppose.
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Resurrecting the thread because I just got a Joyo American.
Seems well enough built.
I had given up on overdriven sounds from my Boss ME series pedalboards.
In contrast, I got good sounding overdriven tones right away from the Joyo.
I didn't buy it to use with the ME70, but I did like it that way, with the ME70 providing a bit of reverb and, importantly, a volume pedal.
I've just started going to a loud jam (good players, but loud). I'm thinking the Joyo will help me cut through a little better and will give me some EQ control when I'm plugged into the house amp. It's a modeling amp with a lot of controls, all to be adjusted in the dark and in a hurry. I'm looking for a summer camp to learn how to use it. I have to figure out how to enter edit mode and adjust the reverb and then turn off everything else without inadvertently silencing the amp.
If I can get that amp to be vanilla-with-reverb and I have the Joyo where I can reach it, I should be able to get both an aggressive enough tone for soloing and something appropriate for comping.
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Ofcourse, regarding the ME line, Boss changed their overdrives/distortions from analogue to digital. I still use the ME8 from 1996 which uses analogue overdrives. They are all really very good. It doesn't do fuzz though. I've thought about getting a separate fuzz pedal but I don't think I'd use it. Anyway, I have a 70s Colorsound Supa Tonebender if ever I need it. Originally Posted by rpjazzguitar
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The EQ on a Joyo American is only 3 band (low, mid, high) but the ranges are well set for guitar and the EQ cut/boost range in each band is pronounced. I typically set up the 6 band EQ on another pedal at home to get the archtop tone I'm looking for. Then, leaving the 6 band alone, use the Joyo American EQ for 'in the room' dial in.
And that's before you get to the presence setting. I typically use none or very little for the clean tones I'm looking for but it does have a noticeable impact on the final sound and I could see using it to cut through a mix.
Finally, while I use this pedal alongside a speaker IR pedal and reverb, I find it sounds pretty good by itself straight into a powered PA speaker.
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Mine doesn't have a knob labeled "presence" -- what does that refer to? Originally Posted by Spook410
The output impedance is 1k. Apparently, a DI box is indicated, but it may depend on the cable runs. Mine are usually 8 feet.
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Originally Posted by rpjazzguitar
It's labeled 'Voice'. Bottom middle knob. Might not be a presence control for all I know but seems to work like one. The IR function is also a variable for me. It's supposed to emulate something like a 1X12 speaker. And I think it does and it's not something you can turn off. Yet, I really prefer running a speaker IR and amp sim behind it using a Joyo Cab Modeler. Sounds good to me and I get a broader palette to screw around with. Joyo American, Cab Modeler, tuner, and a reverb easily fit on a small one row pedalboard with a battery power supply that will run it for a couple of hours.
As for the output I've kind of given up on predicting how tolerant the input circuit is on each speaker so it's become more of a try it and see. My Yamaha DZR10 works fine with the Joyo. I only use a direct box if I need to make a longer run.
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