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July 30, 2021, 10:03:25 PM

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1
Amplifier Discussion / Re: Roland JC120 - Split Line Out for Stereo?
« Last post by Jazz P Bass on July 29, 2021, 12:00:44 PM »
I am simply going by Roland's recommended values.
Leaving out the ground resistor defeats the divider circuit.

Play with the values if you like.
https://ohmslawcalculator.com/voltage-divider-calculator
2
Amplifier Discussion / Re: Roland JC120 - Split Line Out for Stereo?
« Last post by vin97 on July 29, 2021, 06:22:24 AM »
So more volume but higher impedance?
Any chance of hurting the amp?

Because higher level on the line out would be pretty nice. At the moment it is extremely low, basically instrument level. I have to route it through an external headphone amp to get usable levels.
3
Amplifier Discussion / Re: Roland JC120 - Split Line Out for Stereo?
« Last post by Jazz P Bass on July 29, 2021, 12:57:51 AM »
"What would happen if I leave it out?"

You will not have a proper 'voltage divider' circuit.
4
Amplifier Discussion / Re: Roland JC120 - Split Line Out for Stereo?
« Last post by vin97 on July 28, 2021, 11:54:21 AM »
Nice, thanks!
Will have to see if I have a 100 ohm resistor around.
What would happen if I leave it out?
5
Honey Amp / Re: Thoughts on my new Honey Amp
« Last post by Jazz P Bass on July 28, 2021, 11:45:33 AM »
" No power switch, but I can understand the omission, since this is supposed to be highly customizable. I have to pop the battery connectors to power down, but my enclosure choice makes that easy enough"

You could try a 3 prong switching jack that disconnects the battery ground when no cord is inserted.

Like pedals use.
6
Amplifier Discussion / Re: Roland JC120 - Split Line Out for Stereo?
« Last post by Jazz P Bass on July 28, 2021, 11:28:34 AM »
The Line Out circuit uses 2 47K and 1 100ohm resistors for the summing network.
You can disconnect R155 and add a 100 ohm resistor to ground to get a separate feed.
7
Honey Amp / Thoughts on my new Honey Amp
« Last post by mckayprod on July 28, 2021, 11:21:32 AM »
I just built mine over the weekend, and I want to start by saying "thanks" for adding a project to all the conversations and information on the forum.  This is a good way to bring it all together and stimulate more discussion.

Next, stuff I like: Excellent board, quality components...real pro stuff and I appreciate that. The distortion sound is smoother than I expected, especially on the higher-gain end of the tone range. The tone control mellows out any fizziness which could be a problem depending on your guitar/headphones/speaker.

And, my criticisms: Too much distortion, and not enough volume with the gain turned down to the edge of breakup.  I'll modify it to the clean buffer preamp option one of these days. No power switch, but I can understand the omission, since this is supposed to be highly customizable. I have to pop the battery connectors to power down, but my enclosure choice makes that easy enough. Finally, what can you say about the lack of volume from a LM386 that hasn't been said before?  I'm running two 9v in series for +18-ish volts, and this is sufficient for headphones, but just.  I haven't tried a speaker yet.

That's my experience, and I look forward to more SSGuitar projects and discussions!
8
Amplifier Discussion / Roland JC120 - Split Line Out for Stereo?
« Last post by vin97 on July 28, 2021, 07:49:26 AM »
Hello.

I have a 76 JC120 and it only has a mono line out, where both outputs are merged at the jack.
Can I just solder them to separate jacks or could this cause problems for the power amps?
9
Schematics and Layouts / Re: Carvin sx 100
« Last post by nosaj on July 28, 2021, 07:20:02 AM »
Was there DC at the speaker?  If so  lightly take our hand and push the speaker in, it should move smoothly, if it is stiff you may require a new speaker also.  I just had a Kustom powered subwoofer with that chip last nite that died taking out the speaker with it .
nosaj
10
Schematics and Layouts / Carvin sx 100
« Last post by kiwi.payne@hotmail.com on July 28, 2021, 03:59:00 AM »
 Have been fixing a Carvin sx 100w amp .  one of the boards is dated 1997 and has a transformer power supply.
 It has a single chip with 15 pins , Carvin 60-72940 labeled  power amp .

Nothing on the web , but with some serious solvent was able to reveal a TDA7294 100W DMOS Audio Amplifier.
So have one on the way , the line out & send & controls  all work , so maybe it will come back to life with a $10 chip.
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