Ry Cooder's Borderline Special

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Bombacaototal
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Re: Ry Cooder's Borderline Special

Post by Bombacaototal »

sluckey wrote: Thu Jan 16, 2020 8:50 pm You can experiment with 1/2W resistors. Connect the VTL5C1 output directly to your master volume pot. Then clip in different resistors between the VTL5C1 output and ground. A 47K would represent a 50K INT pot set to max, a 1M pot would represent a 1M INT pot set to max, etc. Once you determine the value of resistor that works best for you, then wire in the appropriate value pot according to the schematic. I would start with a linear taper. If you get too much INT change in the first part of rotation, change to a audio taper. If you don't get much INT change until the last part of rotation, change to a reverse audio taper.

The trem sounded pretty nice to me on the last sound clip.
Yes, trem sounds great, just need to get the INT right.

I tried the suggested, started at 1M, 220K, 100K, 68K. It was not great up until this point. Then I tried 24K and it started to be better, 18K (reading 17.85K) was really really good, but 12K (reading 11.9K) is probably the best. 9.1K was too slow I think

As a range I think it needs to be between 10K and 25K
sluckey
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Re: Ry Cooder's Borderline Special

Post by sluckey »

9.1K was too slow I think
What does that mean??? What you are doing has nothing to do with SPEED!

The lower resistance you use, the more it will drag down the gain of your amp. If you used a zero ohm resistor it would totally kill the guitar signal. You'll probably need to compromise between strong trem and amp gain.
Bombacaototal
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Re: Ry Cooder's Borderline Special

Post by Bombacaototal »

sluckey wrote: Thu Jan 16, 2020 9:54 pm
9.1K was too slow I think
What does that mean??? What you are doing has nothing to do with SPEED!

The lower resistance you use, the more it will drag down the gain of your amp. If you used a zero ohm resistor it would totally kill the guitar signal. You'll probably need to compromise between strong trem and amp gain.
Yes, I know. My conclusion is that this specific circuit will probably not work with values much higher than 25K. I can try a 50K pot but it will kill the gain Like a Blackface
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Re: Ry Cooder's Borderline Special

Post by sluckey »

You don't have to inject the trem at the MV pot. Try it earlier in the preamp, like at the volume pot. The guitar signal is smaller there so you would not need as much trem intensity. This means you could use larger INT pot, maybe even a series resistor, to avoid loading of the guitar signal.
Bombacaototal
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Re: Ry Cooder's Borderline Special

Post by Bombacaototal »

sluckey wrote: Thu Jan 16, 2020 10:27 pm You don't have to inject the trem at the MV pot. Try it earlier in the preamp, like at the volume pot. The guitar signal is smaller there so you would not need as much trem intensity. This means you could use larger INT pot, maybe even a series resistor, to avoid loading of the guitar signal.
That’s a great idea!

I tried with 100kB pot, it worked well with pot after 12:30 o’clock/ 1 o’clock. I then went back to the resistors and 100K is very good - maybe comparable to the 24K at MV from before, a tad too quick still. 68K was perfect! 220K doesn’t sound good.
Bombacaototal
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Re: Ry Cooder's Borderline Special

Post by Bombacaototal »

Could we potentially use the spare triode for a stronger trem to allow for a larger INT pot?
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Re: Ry Cooder's Borderline Special

Post by sluckey »

no
Bombacaototal
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Re: Ry Cooder's Borderline Special

Post by Bombacaototal »

sluckey wrote: Fri Jan 17, 2020 2:31 pmno
I was reading again your post about the resistor experiment and I think I did a mistake. I had the VTL grounded on one side and was adding the resistor between the other side (output) of the VTL and the master.

Will repeat it today as you suggested, connecting the VTL output straight to master and on the same point adding a resistors to ground and will report again. First MV then Volume
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Re: Ry Cooder's Borderline Special

Post by sluckey »

We know that the 250KB pot worked from 3 o'clock.
That should simply be a pot taper issue.

Help me understand what 3 o'clock means. When you turn the pot max counterclockwise (min INT) what time is it? When you turn the pot max clockwise (max INT) what time is it?
Bombacaototal
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Re: Ry Cooder's Borderline Special

Post by Bombacaototal »

sluckey wrote: Fri Jan 17, 2020 2:53 pm
We know that the 250KB pot worked from 3 o'clock.
That should simply be a pot taper issue.

Help me understand what 3 o'clock means. When you turn the pot max counterclockwise (min INT) what time is it? When you turn the pot max clockwise (max INT) what time is it?
Max would be 5 o'clock and Min would be 7 o'clock.
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Re: Ry Cooder's Borderline Special

Post by sluckey »

What is the taper of the 250K pot you are using?
Bombacaototal
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Re: Ry Cooder's Borderline Special

Post by Bombacaototal »

sluckey wrote: Fri Jan 17, 2020 2:56 pm What is the taper of the 250K pot you are using?
It's 250KB
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Re: Ry Cooder's Borderline Special

Post by sluckey »

Are you happy with the tremolo effect when that INT pot is set to max?
Bombacaototal
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Re: Ry Cooder's Borderline Special

Post by Bombacaototal »

sluckey wrote: Fri Jan 17, 2020 3:04 pm Are you happy with the tremolo effect when that INT pot is set to max?
I think I know a solution. As I mentioned on one of the previous posts (I edited it so maybe you missed) I was mistakently placing a resistor between the output of the VTL and the Master (instead of adding the VTL straight to master and the resistor to ground). I found out that a resistor between 10K and 24K worked great on that configuration with 12K being probable the best. So maybe I can add a 10K resistor followed by and in series with a 15K variable resistor (not sure what is the nearest standard pot value) as my INT pot. Or a 4.7K followed by a 20KB variable resistor pot. Job done! And it won't kill the gain of the amp
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Re: Ry Cooder's Borderline Special

Post by sluckey »

Sounds like you're just about done. I do suggest trying a linear taper 250K pot.
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