"Enhancer" project
« on: February 16, 2017, 06:50:09 PM »
Hey chaps,

I've got this idea for a project I would need a bit of  h e l p with. I am thinking to build a box to use in the studio for "enhancing" high end on vocals, drum buses etc. The design would consist of a high frequency boost stage inspired by the high band on the 3d Night EQ ( original thread : https://groupdiy.com/index.php?topic=19789.0) and the second stage would be the distortion/saturation stage. I was looking around for a similar simple saturation box build but could not find any that were designed for line level inputs. I did find an interesting design built to be used as a guitar pedal. What kind of modifying would this distortion box's design need in order to work with line level signals and in series with the EQ?

Any pointers, ideas and replies welcome

 I am pretty new to DIY electronics so if this question is painfully stupid, I am very sorry   ::)

Doing the same things over and over again and expecting a different result.


joaquins

Re: "Enhancer" project
« Reply #1 on: February 16, 2017, 10:16:03 PM »
For line level, not much at all, some changes you can do to fit better task maybe.

Change the  resistors around the first opamp, from 100k to 10k, you can also use that opamp as a balanced reciever if needed adding other two 10k resistors. Change that 1µF cap to 47µF. For the output, change the 10µF to 47µF, add a series resistor at the output, 47Ω for example. If you need balanced another 47Ω from ground would make the cold end, having an impedance balanced circuit which is pretty good already, better if you add a 47µF cap in series.

The two 4k7* resistors define the frequency where it starts to work, changing that value (and the next two 4k7 ones) would define the colour of the enhancement, the 1M** resistor defines the gain of the enhancer, maybe could be called harshness or brightness. Of course the 10k pot would control the amount of effect added to the original signal.

JS
If I don't know how it works, I prefer don't turn it on.

Re: "Enhancer" project
« Reply #2 on: February 17, 2017, 05:35:29 AM »
Thanks joaquins! Will definitely take your suggestions into consideration. :)

I'll start plotting and emulating the circuit today, so i'll keep this thread posted.
Doing the same things over and over again and expecting a different result.

abbey road d enfer

Re: "Enhancer" project
« Reply #3 on: February 17, 2017, 11:04:51 AM »
Looks pretty similar to Aphex's Aural Exciter. It was a hit in the 70's but soon people got tired of it.
I've been guilty of building some similar products, but never of using them!
Several manufacturers produced Exciter/enhancer stompboxes; Aphex, Boss, Behringer... butthey seem to have ceased now.
Only BBE with their Sonic Stomp seem to be pursuing that; they use a different principle, though.
Who's right or wrong is irrelevant. What matters is what's right or wrong.
"The important thing is not to convince, but to give pause for thought." (B. Werber)
Star ground is for electricians.

JohnRoberts

Re: "Enhancer" project
« Reply #4 on: February 17, 2017, 11:28:56 AM »
Looks pretty similar to Aphex's Aural Exciter. It was a hit in the 70's but soon people got tired of it.
I've been guilty of building some similar products, but never of using them!
Several manufacturers produced Exciter/enhancer stompboxes; Aphex, Boss, Behringer... butthey seem to have ceased now.
Only BBE with their Sonic Stomp seem to be pursuing that; they use a different principle, though.
Back in the early days of Aurel Exciters, I would try to tune in my FM radio better when I heard the distorted vocals.  :o :o

I never was a big fan of distortion (except perhaps on lead guitar).

JR
John Roberts
http://circularscience.com
Tune it, or don't play it...

abbey road d enfer

Re: "Enhancer" project
« Reply #5 on: February 17, 2017, 11:45:57 AM »
Back in the early days of Aurel Exciters, I would try to tune in my FM radio better when I heard the distorted vocals.  :o :o
Yes, I remember a track by White Lion that had so much of it I thought my car radio had gone duff, but it worked perfectly on the next record...
Who's right or wrong is irrelevant. What matters is what's right or wrong.
"The important thing is not to convince, but to give pause for thought." (B. Werber)
Star ground is for electricians.

Re: "Enhancer" project
« Reply #6 on: February 17, 2017, 12:08:18 PM »
Looks pretty similar to Aphex's Aural Exciter. It was a hit in the 70's but soon people got tired of it.
I've been guilty of building some similar products, but never of using them!
Several manufacturers produced Exciter/enhancer stompboxes; Aphex, Boss, Behringer... butthey seem to have ceased now.
Only BBE with their Sonic Stomp seem to be pursuing that; they use a different principle, though.

Yes! I was aiming for something slightly similar, didn't want to call the name out as it seems to have a bit of a bad rep :D
Doing the same things over and over again and expecting a different result.

joaquins

Re: "Enhancer" project
« Reply #7 on: February 17, 2017, 02:06:59 PM »
  I have the boss stompbox, I didn't knew about it and saw it in a shop, ask to try it out, boring amp (peavey transamp IIRC), boring guitar (low end Cort strat). It changed the clean sound from night to day, I took it home with me. In my setup was much less impressive but still quite useful to have in the floor, quite a few friends tried to stole it from me and I think someone succeed, I haven't seen it in a while.

  For the BBE there was a single chip solution, a Chinese seller had them who sells the wavefront converters, vactrols, and other sort of obsolete audio related components. I can't remember the name, but someone here will.

JS
If I don't know how it works, I prefer don't turn it on.

JohnRoberts

Re: "Enhancer" project
« Reply #8 on: February 17, 2017, 05:04:53 PM »
  I have the boss stompbox, I didn't knew about it and saw it in a shop, ask to try it out, boring amp (peavey transamp IIRC),
I may be a little biased because I know the guys who developed the Peavey transtube technology (solid state tube mimic). ("transamp" was Paul Buffs transformerless mic preamp module). The transamp was a respectable mic preamp technology for several decades ago. 

The year the transtube guitar amp was introduced at NAMM they did a single blind demo A/B switch comparing it to a real tube amp (a Peavey classic I think). The vast majority could not reliably tell them apart.

JR
Quote
boring guitar (low end Cort strat). It changed the clean sound from night to day, I took it home with me. In my setup was much less impressive but still quite useful to have in the floor, quite a few friends tried to stole it from me and I think someone succeed, I haven't seen it in a while.

  For the BBE there was a single chip solution, a Chinese seller had them who sells the wavefront converters, vactrols, and other sort of obsolete audio related components. I can't remember the name, but someone here will.

JS
John Roberts
http://circularscience.com
Tune it, or don't play it...

joaquins

Re: "Enhancer" project
« Reply #9 on: February 18, 2017, 02:16:02 AM »
I may be a little biased because I know the guys who developed the Peavey transtube technology (solid state tube mimic). ("transamp" was Paul Buffs transformerless mic preamp module). The transamp was a respectable mic preamp technology for several decades ago. 

The year the transtube guitar amp was introduced at NAMM they did a single blind demo A/B switch comparing it to a real tube amp (a Peavey classic I think). The vast majority could not reliably tell them apart.

JR

That, I know the transamp, I just confused them.

  I knew you'll come around for that, I didn't mean to upset anyone, I wouldn't choose a 5150 over an AC30 anyway. Still I might be biased because I build my amp my self  ::) I haven't played around with the transtube enough to judge, my second amp is SS and I wouldn't change it for a tube one. There are plenty of nice sounding SS amps and plenty of crappy hollow state amps.

  The guitar mics weren't helping for sure, as generic as Cort uses, against the serious ones mine came with...

JS
If I don't know how it works, I prefer don't turn it on.


Re: "Enhancer" project
« Reply #10 on: February 21, 2017, 05:49:55 PM »
Chaps! So got the saturation bit of the circuit to simulate well on ltspice, thanks for the help!
I'm now looking into the EQ section. Any suggestions how to efficiently strip this circuit to only having the 40kHz boost with a pot + the whole bandwidth signal at the output? I can't seem to figure out how to achieve this, a bit confused about what I need to keep and what not!

As before, any pointers, ideas and replies welcome

Cheers 8)

Doing the same things over and over again and expecting a different result.

abbey road d enfer

Re: "Enhancer" project
« Reply #11 on: February 22, 2017, 01:23:05 AM »
Chaps! So got the saturation bit of the circuit to simulate well on ltspice, thanks for the help!
I'm now looking into the EQ section. Any suggestions how to efficiently strip this circuit to only having the 40kHz boost with a pot + the whole bandwidth signal at the output? I can't seem to figure out how to achieve this, a bit confused about what I need to keep and what not!

As before, any pointers, ideas and replies welcome

Cheers 8)
See attachment
Who's right or wrong is irrelevant. What matters is what's right or wrong.
"The important thing is not to convince, but to give pause for thought." (B. Werber)
Star ground is for electricians.

Re: "Enhancer" project
« Reply #12 on: February 22, 2017, 08:14:44 AM »
Ah thanks! Makes sense. I'll try to get the circuit together now, i'll post the full thing when it emulates properly.
Can't wait to start building it! :P
Doing the same things over and over again and expecting a different result.

Re: "Enhancer" project
« Reply #13 on: March 01, 2017, 02:15:23 PM »
Thanks guys, I think i've got the circuit more-or-less together now, would anyone with a good eye be willing to check it for any fundamental mistakes?

Have I got the inputs, connection between the two units right? Also, i think I want this unit to only output balanced, so how would that be achieved?

Thanks again  8)
Doing the same things over and over again and expecting a different result.

Re: "Enhancer" project
« Reply #14 on: March 03, 2017, 08:25:36 AM »
Anyone?  8)
Doing the same things over and over again and expecting a different result.

Hideki

Re: "Enhancer" project
« Reply #15 on: March 03, 2017, 08:00:01 PM »
Anyone?  8)
Well... some of the circuit blocks make sense, while others do not :)

The hot input has a 1M resistor and a cap, while the cold input does not. Why not? Also, the hot, which is typically considered the positive polarity, goes the the inverting input?

You have swapped the +/- opamp inputs on the sallen-key highpass filters.

After you mix the dry and saturated signals, you have 10k/47u/1M... I can't see any reason for having those components there.

Suddenly, you make the signal (impedance) balanced with 47 ohms and run it to another differential amp to make it single ended again. Why? Is that balanced connection a looooooooong stretch of cable? BTW. the +/- opamp inputs are swapped again here, and it's also wrong for the two last opamps.

I can't figure out how the 40 kHz EQ is supposed to work (it probably doesn't) and loading that poor upper opamp with 200+20 ohms isn't a good idea either.

To easily balance the output, do like you did after the virtual earth mixer. Add 47 ohms (or a bit more) in series with the output and use that as the hot output, then add another 47 ohms (connected to ground) and 10 uF cap in series as the cold output.

Re: "Enhancer" project
« Reply #16 on: March 06, 2017, 07:27:28 AM »
Thanks alot ! I'll make the adjustements.
Doing the same things over and over again and expecting a different result.

Re: "Enhancer" project
« Reply #17 on: March 07, 2017, 03:28:09 AM »
Well... some of the circuit blocks make sense, while others do not :)

The hot input has a 1M resistor and a cap, while the cold input does not. Why not? Also, the hot, which is typically considered the positive polarity, goes the the inverting input?

You have swapped the +/- opamp inputs on the sallen-key highpass filters.

After you mix the dry and saturated signals, you have 10k/47u/1M... I can't see any reason for having those components there.

Suddenly, you make the signal (impedance) balanced with 47 ohms and run it to another differential amp to make it single ended again. Why? Is that balanced connection a looooooooong stretch of cable? BTW. the +/- opamp inputs are swapped again here, and it's also wrong for the two last opamps.

I can't figure out how the 40 kHz EQ is supposed to work (it probably doesn't) and loading that poor upper opamp with 200+20 ohms isn't a good idea either.

To easily balance the output, do like you did after the virtual earth mixer. Add 47 ohms (or a bit more) in series with the output and use that as the hot output, then add another 47 ohms (connected to ground) and 10 uF cap in series as the cold output.

Looks like I'm going to scrap the Night EQ part of the design. Any suggestions of a simple EQ design that would provide me a silky top end?  8)
Doing the same things over and over again and expecting a different result.

Re: "Enhancer" project
« Reply #18 on: March 17, 2017, 01:06:33 PM »
I have made some changes to the design now. Big thanks to the help to the help of this great community!  ;D

Here's the V2 of the design.

I got rid of the Night EQ 40kHz bit and replaced it with a pot to dial the frequency from 1-15kHz.
I've also made some slight changes, but still a bit of unsure if this would work. Would anyone care to give this new  schematic another look?

I can post the circuit file if anyone's interested

Cheers
« Last Edit: March 17, 2017, 01:21:26 PM by Kokoroko »
Doing the same things over and over again and expecting a different result.

Hideki

Re: "Enhancer" project
« Reply #19 on: March 17, 2017, 05:09:23 PM »
This looks better. The high pass filters are still wrong. Swap + and - on the opamps.
You specify the value of the resistors, so why not do the same for the pots?

In your high shelf EQ, 10 uF and 6.8k will give you a cutoff of about 2.3 Hz. Try something like 1.5 nF instead. That gives you 15.6 kHz, and with a 100k pot you can turn it down to 1 kHz. Now, that's only the cutoff frequency of the filter. How you want to specify the frequency of the shelf is not as well defined, so it's up to you.

Either add a capacitor to the hot output or remove the one on the cold. The idea is to keep it impedance balanced, which means using the same impedance for both of them.