Sunrise buffer box
« on: January 01, 2020, 11:21:41 AM »
Hey there,
Im aware that we are not allowed to post schematics of this.... still in production. Still, does anyone have info on whats inside? What opamp they use? Id love to build one in my yamaha thr10. would be much nicer that carrying a seperate box


midwayfair

Re: Sunrise buffer box
« Reply #1 on: January 01, 2020, 02:32:12 PM »
The one I fixed was a Burr Brown FET op amps. I don't remember exactly which one, but it really shouldn't matter that much.

There's really not much to the circuit. It's pretty much a datasheet audio circuit in a steel box.

... Also, it was perfboard wrapped in black electrical tape. Maybe that adds some mojo.  ::)
I'm Jon. Myself's music and things I make: jonpattonmusic.com. My band: www.midwayfair.org. [Disclaimer: PCBs of guitar pedals I've designed are sold by Madbean, 1776 Effects, and JMK PCBs.]

Re: Sunrise buffer box
« Reply #2 on: January 01, 2020, 03:52:42 PM »
Thanks,
Do you think a simple fet buffer like this will do the same? They dont spec input impedance but when building the fet version i guess it should be 1Meg  or up?

https://www.musikding.de/docs/musikding/buffer/bufferschalt.pdf


abbey road d enfer

Re: Sunrise buffer box
« Reply #3 on: January 01, 2020, 04:31:09 PM »
The one I fixed was a Burr Brown FET op amps. I don't remember exactly which one, but it really shouldn't matter that much.

There's really not much to the circuit. It's pretty much a datasheet audio circuit in a steel box.

... Also, it was perfboard wrapped in black electrical tape. Maybe that adds some mojo.  ::)
What brand of tape? That's where the magic is...  ;)
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.

Re: Sunrise buffer box
« Reply #4 on: January 01, 2020, 06:59:02 PM »
Im aware that we are not allowed to post schematics of this.... still in production. Still, does anyone have info on whats inside? What opamp they use?
unwrapped a  brand new buffer box,
the IC has the designation sanded off,  it is a single op-amp.
there was no electrical tape.  the board was encapsulated in yellow shrink wrap.
if you want to know the details,  contact Dave Collins, he designed it for Mr. Kaufman.

abbey road d enfer

Re: Sunrise buffer box
« Reply #5 on: January 02, 2020, 01:06:30 AM »
They dont spec input impedance but when building the fet version i guess it should be 1Meg  or up?
Actually it's about 400k. I think it would be correct for most passive p/u's, even piezo types.
I know some go crazy about high impedance for piezo's, like 10 Meg or so, but I always find it too boomy and need to low-cut.
I found that between 500k and 1Meg works good most of the times.
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.

Re: Sunrise buffer box
« Reply #6 on: January 02, 2020, 01:31:09 AM »
I found that between 500k and 1Meg works good most of the times.
1M2 is my "go to" but yes, 500K sounds better on some pick-ups.   A tweaker's box would allow the load to be altered to suit I guess.

abbey road d enfer

Re: Sunrise buffer box
« Reply #7 on: January 02, 2020, 01:56:46 AM »
the IC has the designation sanded off,  it is a single op-amp.
Several possible candidates, however the claimed current draw (0.15mA) limits the number of potential suspects. And it looks like none of them is particularly low-noise.

Quote
there was no electrical tape.  the board was encapsulated in yellow shrink wrap.
Aah! but it changes everything; shrink tube, particularly the yellow one, has a very different sound.  :)
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.

Re: Sunrise buffer box
« Reply #8 on: January 02, 2020, 06:06:55 AM »
Thanks guys,

Do you think i could bump up the impedance to 1meg on the kit i have posted somehow? Or does anyone have a different schematic? I do think i should aim for a 1meg input resistance.  Thanks a lot

Will this one be higher:
http://www.generalguitargadgets.com/pdf/ggg_buffer_jfet_sc.pdf
« Last Edit: January 02, 2020, 06:16:18 AM by salomonander »

abbey road d enfer

Re: Sunrise buffer box
« Reply #9 on: January 02, 2020, 09:39:45 AM »
Thanks guys,

Do you think i could bump up the impedance to 1meg on the kit i have posted somehow? Or does anyone have a different schematic? I do think i should aim for a 1meg input resistance.  Thanks a lot
Make R1 & R2 2.2Meg and R5 4.7Meg.

Quote
Will this one be higher:
http://www.generalguitargadgets.com/pdf/ggg_buffer_jfet_sc.pdf
Yes, that one is 1Meg, but note it is a source-follower so it is unity gain.
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.


squarewave

Re: Sunrise buffer box
« Reply #10 on: January 02, 2020, 11:30:08 AM »
http://www.generalguitargadgets.com/pdf/ggg_buffer_jfet_sc.pdf
If a 3 pole switch is used, why not use the 3rd pole to deliver power? Then you don't have to unplug it to save battery. With an extra high Z input and careful pop control you could do the same with 2 poles.

Although I don't understand why someone would bother with a one transistor circuit like this. It's a little too simple. No drive. An op amp is worth the extra few mA. NJM4556 works is battery friendly and has excellent drive (same op amp used in the O2 headphone amp).

abbey road d enfer

Re: Sunrise buffer box
« Reply #11 on: January 02, 2020, 11:45:13 AM »
If a 3 pole switch is used, why not use the 3rd pole to deliver power? Then you don't have to unplug it to save battery. With an extra high Z input and careful pop control you could do the same with 2 poles.
OP wants to install it in his Yamaha THR10, so I suspect he would power it post power switch.

Quote
Although I don't understand why someone would bother with a one transistor circuit like this. It's a little too simple. No drive. An op amp is worth the extra few mA. NJM4556 works is battery friendly and has excellent drive (same op amp used in the O2 headphone amp).
Being bipolar, NJM4556 is bound to have high input noise current, which is incompatible with high-Z sources. Its operating current of 9mA typ., which is not an issue in this particular case, can be a no-go for battery powered applications. There are several JFET opamps with a comparable input noise voltage and much lower noise current and much smaller operating current.
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.

PRR

Re: Sunrise buffer box
« Reply #12 on: January 02, 2020, 12:02:43 PM »
Why does a Yamaha THR10 need some "buffer box"?

abbey road d enfer

Re: Sunrise buffer box
« Reply #13 on: January 02, 2020, 12:15:30 PM »
Why does a Yamaha THR10 need some "buffer box"?
Probably for the same reason he carries a separate box...  ???
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.

Re: Sunrise buffer box
« Reply #14 on: January 02, 2020, 12:44:41 PM »
Thanks a lot guys. I will try upping the resistors as suggested. Ill let you know.

Whoops

Re: Sunrise buffer box
« Reply #15 on: February 04, 2020, 11:01:17 PM »
Take a look also here, it's a very nice article on guitar buffers:

http://www.muzique.com/lab/buffers.htm

Re: Sunrise buffer box
« Reply #16 on: March 06, 2020, 12:51:34 PM »
Make R1 & R2 2.2Meg and R5 4.7Meg.
Yes, that one is 1Meg, but note it is a source-follower so it is unity gain.

Hey mate,
Are you certain about the math here? I just built this and get a big level drop with the resistors you recommended.

abbey road d enfer

Re: Sunrise buffer box
« Reply #17 on: March 06, 2020, 07:26:11 PM »
Hey mate,
Are you certain about the math here? I just built this and get a big level drop with the resistors you recommended.
Is it the FET or the Si NPN version?
The SiNPN version would not work well but the FET should. What type of capacitor have you for C1? Electrolytic would be too leaky. You don't need 1uF with the FET, 0.1uF is largely enough. Note that this buffer is a voltage-follower with 0dB gain.
« Last Edit: March 07, 2020, 02:57:44 AM by abbey road d enfer »
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.

Re: Sunrise buffer box
« Reply #18 on: March 07, 2020, 05:34:30 AM »
Is it the FET or the Si NPN version?
The SiNPN version would not work well but the FET should. What type of capacitor have you for C1? Electrolytic would be too leaky. You don't need 1uF with the FET, 0.1uF is largely enough. Note that this buffer is a voltage-follower with 0dB gain.

Thanks mate, maybe i did some error.... but built this twice with the same result. And yes, the fet version. Ill try around more im certain its my fault somehow. Just wanted to double check the values. Thanks for your quick reply! Oh and i use wimas with the correct values.

Maybe i need another circuit after all... even if this was working.  My yamaha does not power the sunrise pickup really. Its way too quiet
« Last Edit: March 07, 2020, 05:37:33 AM by salomonander »

abbey road d enfer

Re: Sunrise buffer box
« Reply #19 on: March 07, 2020, 12:40:08 PM »
Thanks mate, maybe i did some error.... but built this twice with the same result. And yes, the fet version. Ill try around more im certain its my fault somehow. Just wanted to double check the values. Thanks for your quick reply! Oh and i use wimas with the correct values.

Maybe i need another circuit after all... even if this was working.  My yamaha does not power the sunrise pickup really. Its way too quiet
Did you really experiment more gain with the original values?
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.


 

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