bigPIMP wrote:
basically I figured get rid of the in and out buffers.. the circuit cleans up better on the vol knob of the guitar, less muddy, more responsive.. use a tl072ACN for the jfet input buffering.. it has one in it.. tone control doesnt need the 25K pot at all it sounded and felt better for what I do with a 2K to 10K device depending on your roll off cap and feedback loop properties..
try back to back darlingtons is a straight up ts9 with a .1 roll off cap instead of a .22 you will begin to understand where the best tweaks are in this type of circuit... Its all a personal thing.. I found out a lot just by modding and re modding a ts5..
Thanks for the response. Just another quick question or two. I'm unfamiliar with Darlingtons, I assume they are a type of diode? And, do you prefer symmetrical or asymmetrical clipping in the Eternity?
I look forward to trying out some of these things myself, although I think I will add an output buffer and see how it works out.
a darlington is a transistor.. You turn it into a diode by attaching the base to C or E I prefer symmetrical I feel it has more sustaining properties..
BUT for the E its the chip that makes it.. its the only thing I do that IC based.. The chip is the deal no matter what way you set it up..
Angle Loss wrote:Unfortunately this conversation is moving in a bad direction. Perhaps we could bring it back around to tone and circuit discussion.
bigPIMP, could you share some of your design philosophy as you have changed versions in the Eternity? What was the evolution of the design?
How do you feel about input and/or output buffers on the Eternity? Do they take away from the sound in your opinion? What are the sweetest parts of the circuit to tweak?
basically I figured get rid of the in and out buffers.. the circuit cleans up better on the vol knob of the guitar, less muddy, more responsive.. use a tl072ACN for the jfet input buffering.. it has one in it.. tone control doesnt need the 25K pot at all it sounded and felt better for what I do with a 2K to 10K device depending on your roll off cap and feedback loop properties..
I've noticed the same thing on many designs...as soon as I remove the buffers, I get better dynamic range...at least with MY guitars. I'm sure that for guitars with "extremely weak" or "extremely high output" pickups, the buffers help....but for me, with typical singles and humbuckers, i get better "feel" from ditching the in / out buffers on most pedals.
I completely understand the input buffer removal, but what about the output?
One of the things I didn't care for the Eternity was that it drastically lost treble in long chains. Putting a buffer immediately after it restored high end--although a little too much IMO, but it sure helped with dark amps. I noticed that people had wildly divergent experiences with the E, some claiming it to be way too dark and others very bright.
The output buffer will of course affect the tone and frequency response, but the feel as well? One of the things I want to try is experimenting with an output buffer on a SoS/E type circuit, but try to make it a less bright than the typical stock TS output buffer.
Or maybe ditch the active tone control and use the second half of the IC for the buffer. Make the tone a SWTC between stages and then add a couple of low pass filters after the output cap? Of course, that gives you a very different pedal. Maybe add a jfet stage after the volume control set to low gain to sweeten it up, and lower the drive pot of the first IC stage to 100-250k.
If you check some SHO in a shop, you'll notice that every box has it's own sound, some are soft sounding others are stiff, some are middy and others more bassy sounding and less trebly.
I don't care much about a given schem or tinker about if it's 100% or 95% original. For me it's a only a basic circuit and I seldom built a 1:1 clone.
Before I build a FX after a given circuit I make a specification for the parts and in most cases I define high grade caps and electrolytics (I never use NP or P-electrolytics for decoupling).
After the first listening test comes some finetuning and maybe some modding.
Swapping a 2N5088 for another 2N5088 in the same circuit can change the sound from soft to hard due to different HFE and a STM LF353 sounds nothing like a NS 353N.
If you want to build a 1:1 sounding clone you'll have to spend a lot of time for finetuning the sound of the clone . Furthermore you need the original for A/B testing and comparing and you have to use identical parts
I don't care much about a given schem or tinker about if it's 100% or 95% original. For me it's a only a basic circuit and I seldom built a 1:1 clone.
I never really make 1:1 clone either - I have done recently but I've gone off it again. It's fairly mundane to just whip somehting out without thinkng about. I've gone back into my super tweaker mind set Much more fun!
Angle Loss wrote:Unfortunately this conversation is moving in a bad direction. Perhaps we could bring it back around to tone and circuit discussion.
bigPIMP, could you share some of your design philosophy as you have changed versions in the Eternity? What was the evolution of the design?
How do you feel about input and/or output buffers on the Eternity? Do they take away from the sound in your opinion? What are the sweetest parts of the circuit to tweak?
basically I figured get rid of the in and out buffers.. the circuit cleans up better on the vol knob of the guitar, less muddy, more responsive.. use a tl072ACN for the jfet input buffering.. it has one in it.. tone control doesnt need the 25K pot at all it sounded and felt better for what I do with a 2K to 10K device depending on your roll off cap and feedback loop properties..
try back to back darlingtons is a straight up ts9 with a .1 roll off cap instead of a .22 you will begin to understand where the best tweaks are in this type of circuit... Its all a personal thing.. I found out a lot just by modding and re modding a ts5..
Props to BigPimp for intelligent discussion on his design!
+1 to Piher pots! Nice to see someone using something different than Alpha for a change. I'm currently trying to shoehorn a big Allen-Bradley industrial pot into a 1590B enclosure.... the battle isn't going well.
"Analog electronics in music is dead. Analog effects pedal design is a dead art." - Fran
The piher pots are great, very smooth and noise free I like them. I think I'll use them when I finish up my new OD. Like you say - it'll add a bit of the old mojo factor
I believe there are two layouts for this pedal.
The first is the "Burst" and the second is the "Roadhouse"
From what I am hearing the "Burst" sounds better with the "Roadhouse" sounding more like a bufferless Screamer.
Both are basically buffer less Screamers.
Anybody want to see the schematics I have for it?
Yes, and of course there now is the Cusack Eternity complete with it's smt parts. No idea which layout they used but if you made a Tube Screamer pcb you can make an Eternity.
The "Magic" chip is most likely a JRC chip.
Look at it this way, it has to be a dual op-amp which would limit the possabilities. 4558
soulsonic wrote:+1 to Piher pots! Nice to see someone using something different than Alpha for a change. I'm currently trying to shoehorn a big Allen-Bradley industrial pot into a 1590B enclosure.... the battle isn't going well.
Does Piher make log pots now? I have only seen the linears at Mouser. I've been interested in trying them for some time.
Much more fun!
