LTD Silver (thumbs up !!)

[Xavier]

Just wanted to share my thoughts about this circuit David Barber graciously posted a while ago.

After many builds, there are just a few ones I'm really satisfied with. Until now it was the mosfet booster and the Dr. Boogey, now add a 3rd one, the LTD Silver.

I have lost the count of how many TS-type OD's I have built. I have been looking for a low gain OD to spice up my clean sound for almost a year. This also includes some circuits like the Peppermill, which don't sound really right to my ears.

This circuit must be the better low gain OD I have ever tried so far. Clean, "transparent", smooth and elegant, for the lack of a better term. I guess there's many combinations when trying different cap and resistor values in order to tune the right tone out of the circuit, but David Barber definitely has the ears for this.......... this circuit is definitely worth the build.

Now I need to urgently put my hands on a Dirty Bomb distortion. If he makes the OD's sound this good , I can't imagine how a distortion will turn out.....

As a happy Direct Drive SS user for 3 years (has never left my pedalboard), I can oficially say I'm addicted to Barber's designs............thumbs up for the LTD silver !!!

[Ripthorn]

Good to hear a review of this.  I have it on my list, but there are still a couple to go before then.  Thanks.

[Ben N]

Thanks for the review. Out of curiosity, how many controls did you bring out front, i.e. stuff like presence, mid & bass that Barber has as trimmers? If you kept them on the board, how much fiddling did they take to get your eq right?

[DougH]

Glad to hear it sounds good. I love the simple elegance of that design - nothing that doesn't need to be there and the freq shaping controls etc look very smart. And- it's definitely not a derivative of a tube screamer.

[Xavier]

I have built it just as it is, with gain , vol and tone on top, and the rest as trimmers.

The bass trimmer has definitely A LOT to do with the final result, I just set it "flat" and even with the uneffected signal. The mids and brilliance trims are more subtle, but noticeable.

That's the good thing about it..you put everything at noon and it already sounds good but VERY natural. It makes the guitar sound "more", it's hard to describe, but I swear I hear more harmonics . Every setting is usable.

I said TS derivative because of the diodes in the FB loop and because except for the filtering, looks very TS to me. I don't really care though. It sounds good and that's what counts

[DougH]

I said TS derivative because of the diodes in the FB loop and because except for the filtering, looks very TS to me.

Oh, I didn't catch that and my comment wasn't directed at you.

(After looking at the L.A. Boutique Screamer I was truly happy to see something that wasn't based on a TS. )

[skiraly017]

The bass trimmer has definitely A LOT to do with the final result, I just set it "flat" and even with the uneffected signal. The mids and brilliance trims are more subtle, but noticeable.

In your opinion, is it worth moving the trimmers to the outside?

[bean]

Having built it, I'd say it is worth moving the bass and mid to actual pots. The presence, not so much.

[Xavier]

Today I'll take it to my band practice and will see, nevertheless I've been fiddling with it a little more.

I would not really need any more pots outside. Even the treble could be a trimpot since is also subtle...........Just gain and volume is more than enough , I like simplicity. I have the mids trimer full on, bass to match the original signal, and presence at 90%, works with my setup.

Maybe what you could do is add some of these mini-pots like on the MI Audio pedals.

[Ben N]

Or those panel mount pots that are adjustable only with a screwdriver. Mouser has them, although I can't find them just now.

[DougH]

bass to match the original signal

In my experience, this is why I find bass controls in pedals not very useful. Once I tune the circuit where the bass response matches the bass in the bypass signal, I'm a happy camper.

[danielzink]

What's everyone using for an opamp ?
I can't seem to source a JRC072 anywhere.

I've got OPA2134's, TL072's etc. hanging around.....

Just wondering.

Thanks, Dan

[David Barber]

What's everyone using for an opamp ?
I can't seem to source a JRC072 anywhere.

I've got OPA2134's, TL072's etc. hanging around.....

Just wondering.

Thanks, Dan

Fortunately the ubiquitous JRC 4558 and JRC 4559 both work well in this circuit, a Burr Brown OPA2604 works well for a little more fidelity. 

[Xavier]

I tried several of them: JRC4558DD, 4559, LF353, OPA2604 and 2134, TL072, TLC2272,........

Given the low gain nature if this circuit, I found the good old 4558DD the best sounding of them all , followed closely by the LF353. Cusiously, OPA2134 sounded really bad in this circuit..............splatty and rough  .

[slacker]

I've tried a TL072 and a TS272 (TLC272) in mine and both sound great. There's not a lot of difference between them but the TS272 is slightly cleaner and somehow more refined if that makes sense.

When I box it up I'm tempted to make the mid control an external pot, or possibly add a toggle to select between full mids and a preset lower level. I think the bass control is more of a set and forget, might be useful as a pot if you use different amps and guitars though. On mine the presence control doesn't do much, but I've got a naturally bright rig, with something darker it might be more noticeable. Like David mentioned in his original post the tone control is subtle but useful.

Overall I really like this circuit it's nothing earth shattering but it's very good at what it does. To me it does what I've always liked about the Tube Screamer in that it's pretty neutral and  basically just sounds like you've turned your amp up.

[mattpas]

Is a NJM072BD from Mouser the same as the JRC072?
When you look at the Data sheet it brings you to the New Japan site and up top it does say JRC.

[cpnyc23]

NJM = JRC

-chris

[liquids]

Another pair of thumbs up for this circuit!  I just breadboarded it...

I've never found anything I like for sweet overdrive with the neck pickup of my #1 and 'only' guitar (a 335 with a Seth Lover).  Never.  I'm stunned! This will do it for me!  Ive slowly shyed away from op-amp overdrives in general, but this thing is killer! 

Tweaking it - I'd definitely be moving the bass and mid trimmers to the front.  Presence - I'd like to control it externally, but for most peoples uses, an internal trimmer would be fine. A toggle would probably even be good enough, but I may end up using an external pot anyway...

First off, the tone control seems super subtle to me. I checked it twice to make sure I wired it correctly, but checking Duncan's tone stack calculator confirms it's subtlety.   I think if anything I would consider moving it  inside as a sort of "global tone control" if anything, as I lset it all the way to the 'brighter' side and left it there.  I may still need to work with it though, maybe it isn't correct... I tried it without the tone stack, and the tone 'stage' more so seems to suck gain, but in a good way, like the tone stack in a fender amp...it does keep things a little cleaner, and sweeter (but with slight mid boost actually according to the duncan calculator).  And of course, it can cut treble if you need that.

I didn't have a 1M pot etc, so I just used a 100k audio for the gain, and that worked fine for me. Setting the gain low (with the 100k audio), it's pretty dark, but can be pretty sweet if you tweak the mid and bass to taste.  Turn it up a bit and it gets clearer, and you move into the range with the edge-of harmonics.  Here, the bass and mid really come into play - with mid around 1K here, you get a 'blackface' sounding EQ, with the mid at 10k (as Dave said is near stock) the mids 'bark.'   I liked the blackface thing here, but was also digging dark and sweet single notes with the mids at 10k, all with the bass trimmed to taste--here the bass seems more like dialing between 'dark' or 'clear,' never becoming bass shy or farty, and overall very useful.

Turn up the gain knob to get some hair, and now I wanted to re-EQ the whole thing.  Less bass cut and more mid here, compared to how I had it set, was necessary...which is why, to me, I'd want these pots outside.  Tune in the EQ and it can do the 'hairy overdrive' thing quite well (though I typically just roll back on my dirt pedals for this tone currently) but with a totally different EQ than I'd use for the sweeter thing. Surprisingly good tones here when tweaked!  Likewise, Here I'd also use more of the presence cut to smooth out the rough edges which is how that comes in to play...but come to think of it, just turning down the tone knob at this point might be even better...I'll have to try that.

All that being said, I'm amazed and humbled by Dave's skill...it's a beautiful circuit, and for me, it gets a convincingly natural edge-of-overdrive bluesy sound that accommodates my neck humbucker-- something no other pedal I've demo'd has done well.  I'd started to loose hope that any circuit could, as even the things I've built hadn't gotten that close...until now!

Dave, thanks.  I also have a lot of love for Barber stuff, and I both use, and regularly recommend Barber pedals.  They're extremely affordable, too, which makes it easier to convince guys who have only considered buying boss pedals to try them....     And now with the Dirty Bomb, they've even got something for those tone-loving metal heads!   

[orangetones]

I'd like to chime in that this is a fantastic overdrive!  I have it on the breadboard right now and it is great sounding!  This one is going stright into a box!

[drewl]

Great, thanks for the review!
I've got one about half done, have a nice painted box all ready for it as well a bunch of opamps to try.
I was trying to figure out which pots to be on top, and you helped with that.
I'm going to go with gain, tone and vol.
pulled the mini  trimpots off some fried boards at work for tweaking the circuit.