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Author Topic: Lab Series L5 preamp in a box: power handling & biasing  (Read 12729 times)

phatt

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Re: Lab Series L5 preamp in a box: power handling & biasing
« Reply #15 on: December 28, 2015, 06:34:11 AM »

Thanks heaps for that link, Some interesting observations in all that.

Obviously driven by the simple desire to build an amplifier that he would want for himself, over built and bullet proof.   Hey I like the guy already :dbtu: :dbtu:

An interesting point here;
I quote;
"We should be quantifying what an amplifier does to the signal, not
how it does the job."

He has my vote on that. 8)
Phil.

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Re: Lab Series L5 preamp in a box: power handling & biasing
« Reply #16 on: February 07, 2016, 10:01:47 PM »
I'm going to spare all parties some grief here. Would you be the kind of guitar player to turn the amp on '10', and turn your HB equipped guitar down to volume '2' to get a clean sound? This is what BB did/does with his Fender Twins, and also what he did with the L5 when he used them. This is the 'secret' recipe for getting the L5 to perform as it did for BB. They have a noticeable hiss when running this way, but certainly fine for live play.

So, if you were to ask me why the Lab series amps didn't catch on, it's as simple as what I've written. BB just happened to approach the L5 as his experience taught him and the result was, well, very usable for him. His way was not like most other players, although I did meet one local pro guy (many years ago) who did figure this out. Imagine my surprise, me owning the same amp and not even getting close to what he had going on. It was laughable but I was not beyond asking him how he was doing this. Talk about a light bulb moment! The idea of making a preamp pedal to capture this result seems virtually impossible, but carry on.

phatt

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Re: Lab Series L5 preamp in a box: power handling & biasing
« Reply #17 on: February 08, 2016, 02:13:28 AM »

Yes with the L5 it would likely work well but you will have to forgive me I'm having trouble keeping a straight face about doing the same with a Twin,,, Oh how We wish it was that simple. :lmao:

Might just get away with it at rock concert levels but even then, the SPL difference would be too large to be usable.
For the rest of us players it's lower level gigs and you just can't do that stuff if you want the gigs.


Unless I'm the last to know the L5 is a big powerful Amp with a very good compressor which means you can set the absolute Level via a master volume to any level and still retain most of the sustain/compression. You can't do that with a Twin. well not a stock one at least.

The few times I've had the misfortune to play Big Fender twins you would have to be insane loud before they would compress making it unusable for smaller gigs, of course some of the early twins where of much lower wattage and likely some were K biased giving much earlier compression in which case sure it would suit that style of playing.
I'd hazza guess and say a fair chance the Twins BBKing played through were likely not Stock so it's anyone's guess as to what circuitry was inside. xP
As it's highly likely I will never get close enough to even sniff a real L5 I have to work within the limitations of off the shelf equipment or in my case go on a 20 years endeavor to find another way to to do same or similar, as in teach myself DIY electronics.

Today likely Many preamp circuits can do the same thing but understand the mindset of the market place.
An amplifier these days has to look like a Mack truck, has to be loud and have many knobs and must have all the extras built in. Somehow a pedal or small preamp no matter how clever just does not have the same chick pulling effect as a big loud quad box with checker plate head on top. Oh and it must have at least one Valve (with blue led glowing underneath)

I've made enough circuits to fill a shed full of land fill pcbs and on the rare occasions I've had a few light bulb moments. As much as I've always wanted a one rig that does it all in one box I've gone back to pedals as it's just so much less hassle and it's easy to modify on the fly.

I've been using the simple Compressor I mentioned earlier and I've played through enough gear to know that even though it may not be technically as slick as a real L5 it's dead easy to build and way way cheaper than trying to purchase a Real L5. and way more useful than a truck load of brandname amps.
Those are just my observations,
Phil.

Enzo

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Re: Lab Series L5 preamp in a box: power handling & biasing
« Reply #18 on: February 08, 2016, 05:01:52 AM »
I have an L5 in my shop right now, guy is coming for it this evening.

I never liked that compressor.  It confuses many guys as well.  On most compressors, you turn the knob up to get more compression.  On the Lab series, the knob is a threshold control, so the more you turn it up, the less it compresses, ie the threshold goes higher and you trigger it less.

J M Fahey

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Re: Lab Series L5 preamp in a box: power handling & biasing
« Reply #19 on: February 08, 2016, 10:04:13 AM »
Yes, and higher threshold not only decreases compression but also increases output level, so turning knob clockwise does the exact opposite than what players expect: smooth even constant volume output for loong sustain.

Typical of Engineers technically savvy but neither players ... nor listening to them.
I mean their ideas and complaints, besides their music.

On the contrary, the Threshold control is what the Doctor ordered for, say, a Radio station or vinyl disc cutting Engineer, so they finely tune "up to" what maximum level they can reach (transmitting or cutting)  without splattering into adjacent Radio/TV channels or having a record groove swing so much as to touch the one besides it, which is a catastrophic failure and means junking the Master disc and starting again on a new blank.

I imagine one of these short sleeve white shirt , glasses and lots of pens in a belt holder Engineers staring glassy eyed to a tatooed pierced wild hair torn clothes Heavy Metal player (how's that for stereotypes?  :lmao: ) and saying: "what do you mean that's a sh*tty compressor?  it's the circuit very successful model made by Pomona Electronics (or some similar name) and used by KJYY FM in LA"
Oh well  ::)

B y the way, it *can*  be setup to work very well, just it's a PITA and counter intuitive.

I bet BB set up his amp *once*  and Krazy glued knobs (or pot shafts)  in place , then the *only* knob he moves is the guitar Volume pot .
He uses it "like an old Twin but louder"   ;)

mexicanyella

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Re: Lab Series L5 preamp in a box: power handling & biasing
« Reply #20 on: February 27, 2016, 12:08:18 AM »
Hope to hear how this project works out, and what aspects of an L5 appealed to you to make you decide to emulate one in pedal form. Interesting idea.

Phatt, another place to hear a Lab L5, doing a different kind of thing, is on the first four albums by King's X. Ty Tabor used an active Fender Strat Elite and a L5, and via its line out drove a PA-type power amp and multiple 4 x 12 cabinets, as heard here: 

https://m.youtube.com/watch?v=p9sO3bcWdpM

He used the higher-gain channel and got a distortion sound that some people, including me, really like. I think he used some outboard graphic EQs, FX processors for chorusy/delay/reverb stuff...but the dirt and basic tone was L5. He has said in interviews that he used to house the L5 guts in custom rack chassis to disguise what they were, in fact. The video manages to convey the distortion character pretty well...and it was similar on the band's recordings and when I saw them live in '92. All I could see onstage of the rig was four Yamaha 4 x 12 cabs, but the L5 crunch was unmistakeable. I was kind of bummed when he switched to Mesa stuff later on, and got more hyped and spitty sounding.

There's a Youtube guy who nails the tone with the same basic rig...an active Strat Elite and a L5 combo, showing how to play some King's X stuff. His Youtube name is The Scunion...check it out.

I have a BB King video here where he mentions having used the L5 and liking it. But yeah...his whole approach is something loud and clean, cranked hard enough to punish the speakers, and throttled with the guitar controls and picking dynamics.
« Last Edit: February 27, 2016, 12:23:39 AM by mexicanyella »

phatt

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Re: Lab Series L5 preamp in a box: power handling & biasing
« Reply #21 on: February 28, 2016, 05:22:52 AM »

Hey thanks Mex,, that's very helpful,, now I have a decent reference point to go by. :dbtu:

My setup is obviously not as thick as that but heck I only use (and need) a small rig.

The little compressor I mentioned in combination with a simple booster and the PhAbbtone can certainly pull off very similar results.
I should try and get a sound sample up with my setup so you can all make your own judgements.
But my hard drive is going rather soft on the inside so a major fix up first.,,, I'll be back later,,, of course that could be a while if the partition copy fails.  might need a whole new setup. wish me luck. :-X
Phil.

mexicanyella

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Re: Lab Series L5 preamp in a box: power handling & biasing
« Reply #22 on: March 01, 2016, 09:24:45 PM »
By all means, please record some clips of it doing its thing. I liked the last ones you posted.

I saw a Lab Series L3 1x 12 combo for sale at a store yesterday but did not get to try it out. I will try to get by there soon and see what it's about.

solderdripper

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Re: Lab Series L5 preamp in a box: power handling & biasing
« Reply #23 on: March 02, 2016, 04:04:33 PM »
Hi guys, I'm a LAB Series nut and enough of a lurker on here that I registered to chime in with this barely-relevant nugget -- I found this earlier today, actually. http://www.premierguitar.com/articles/Interview_Ty_Tabor_Kings_X 
Interview from 2011, Tabor says that he has two pre-amps specially built for him by Egnator, "We call it the Gretchen Module because it was designed to emulate the Lab Series L5 as best as possible, and they did a really good job at getting very close on that."

I still don't know if it is the compressor or the multifilter that he likes best.  :)

mexicanyella

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Re: Lab Series L5 preamp in a box: power handling & biasing
« Reply #24 on: March 02, 2016, 09:35:07 PM »
I think I remember reading that he did not use the compressor...don't recall what he did/did not do with the multifilter.

I played through one of the larger lab heads once (L7? L9? L11? can't remember) but I recall that it did have a unique way of breaking up that seemed at once dynamically responsive and not really sounding like Marshally rock tube amp distortion at all. I liked it but it was priced out of my range at the time. I can see how that line of amps would attract a following.

J M Fahey

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Re: Lab Series L5 preamp in a box: power handling & biasing
« Reply #25 on: March 29, 2016, 08:47:34 PM »
I was onstage in BB's visits to Argentina, he both used L5 and Silverface Twins full blast, no big deal, but shows were either in Buenos Aires Luna Park 12000 to 15000 seats and Obras Sanitarias, some 8000 seats, full blast amps were pipsqueaks there.

galaxiex

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Re: Lab Series L5 preamp in a box: power handling & biasing
« Reply #26 on: October 30, 2016, 07:50:20 PM »
Sorry to necro bump this thread, but the OP has had this project finished for some time now and selling circuit boards for it.

I mention this cuz I bought one,  ;) and am very close to finishing it up.
Just waiting for a couple of parts to arrive.

I will post here in the effects section when I got it done.

Here's a link to his website and the project.

https://aionelectronics.com/project/lab-series-l5-preamp/

and a link to madbean pedals forum where he posted about this project.

http://www.madbeanpedals.com/forum/index.php?topic=22746.msg223193#msg223193

Cheers!
« Last Edit: October 30, 2016, 08:26:09 PM by galaxiex »
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phatt

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Re: Lab Series L5 preamp in a box: power handling & biasing
« Reply #27 on: November 03, 2016, 04:05:37 AM »
Hi galaxiex,

Thanks for the links, interesting. :tu:
I noticed down the end of the page at https://aionelectronics.com/project/lab-series-l5-preamp/
Some comments regarding the way Ty Tabor used the L5 amplifiers.

It seems Ty does not use the compressor which throws a whole different slant on the subject of the compressor section. Maybe he just wanted the tone filter section for some extra tone tweaking. The article then goes on to say the preamp output was sent to a Messa 2Ninety which is a big Valve power rig.
So that would certainly give compression at high output levels which is fine for large live venues but not possible at low volume as just like a big fender twin down low they are just as clean as most SS rigs.

But then a few posts back *mexicanyella* noted he changed the setup
(another guitar player in search of the mojo)  :lmao:

So in the end who knows what is being used and how good or bad some of this gear really works. xP

On the Madbean link I noted a few comments regarding building of the project where some issues were raised. I know from building a few of the well known compressor circuits that used the ca3080 they can be noisy and fussey to setup.

FWIW,,My observations having had a marshall ED comp, a boss CS2 and CS3 and a couple of breadborad test circuits all on the bench at the same I've noticed that the ca3080 circuits are noise prone.
The Boss CS3 is the exception as it uses a THAT chip and is far less noise prone to all the others I had at the time, though it still can't reproduce the classic Valve compression. :grr :grr :grr

needless to say I gave up on compressor circuits. :'( :'(
I went on to try all sorts of hair brained ideas :duh  that were in the end too complex and fiddly to be of any real use. (some I posted here)
But then that chap *Mictester at FSB* posted that simple comp circuit I mentioned on previous page and it was impressive. must be the most simple compressor circuit I've ever seen and it does deliver the compression WITH the magical rattle. <3) <3) <3) <3) <3) <3)

Why am I saying this? Well because it works for R&R guitar and a lot of DIY'ers out there will be hard pressed to find something that delivers that classic sound of a valve amp on the edge of breakup.
No setup fiddling and only 2 knobs. Except for the LDR which you have to make from 2 Leds and an LDR and a piece of shrink tube all the other parts are off the shelf. Bang for buck it's likely hard to beat.

If I ever work out how to make up a video of my gear I'll post a clip of my setup on utube but not sure how well it will reproduce the effect and feel of what I hear through a small cheap camera. :-\

Phil.

galaxiex

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Re: Lab Series L5 preamp in a box: power handling & biasing
« Reply #28 on: November 03, 2016, 10:10:59 PM »
Hi Phil,

Thanks for all that.  :)

'course my main motivation for buying/building this kit was not solely for the compressor.  ;)

More I was curious about this amp (the actual Lab Series L5) and since I'm not likely to own one,
or even be near one anytime soon, aaaannnnd...
I'm a sucker  ::)
for a somewhat unique, and what appears to be, a very well thought out project.
Not to mention it looks killer too.

I am "familiar" with the L5 only in that I actually remember the ads for them from back in the day,
and as an impressionable youth the ad writers prose had an impact on me.  :o

Didn't hurt that BB King used them too.  8)

I wouldn't know if this pre-amp nails the sound of the original L5 or not,
but I want to explore its potential, whatever that may be.

I saw your original post about the Mictester comp and have looked at his original posting and read thru the thread.
I am very keen to build one....  :)

I'm so neck deep in so many projects right now..... but I will get to it.... eventually....

I was playing a modified Ross comp from Guitar PCB dot com aka the MoRC, and liked it for a while...
but its now gone from my pedal chain as I completely changed my setup.

Previous setup.

Fender Nashville Tele > MoRC comp > EA Tremolo > Boss Blues Driver > Blackstar Soloist 60

New setup.

Fender Nashville Tele..................... tuned std >
Keef Micawber Clone.....tuned 5 string open G >  > Jack Orman 3 way mixer > Boss TU-3 > Boss SD-1 (Keely mod done by me)  > 1978 Deluxe Reverb
Fender 52 FSR Tele...................tuned open E >

I love the Orman mixer based on a TL071.
It adds a slight 3db boost, but best of all when I need to change guitars,
I don't have to un-plug one, and then plug-in the next.
I just put one down and pick up the next and hit the footswitch.

All 3 guitars stay plugged in and the box has a footswitch and LED for each.  8)

(I'm gettin too old to have to bend over pluggin cables alla time.
It's hard enough to sling those axes over my shoulder for a 1 hr set)  ;)

Sorry to ramble on...

Thanks for your thoughts on this  :) ,
and I really will build that Mictester Comp..... curious to see how it works with the Deluxe.

PS I'd love to see a vid and hear your setup sometime.  8)


« Last Edit: November 03, 2016, 10:12:26 PM by galaxiex »
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phatt

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Re: Lab Series L5 preamp in a box: power handling & biasing
« Reply #29 on: November 07, 2016, 03:08:12 AM »
Thanks for sharing your ideas,
I'm not able to record anything right now but meantime here is a pic of my pedal board.

image sharing sites

My Aim is not about making the best amplifier it's really more about extracting the best sound from basic equipment. I refuse to except that one has to empty my bank account to achieve great guitar sound.
You only have to google a few mojo words to find all the greatest pedal claims of tone nirvana,, but the demonstrations are ALWAYS done through very expensive amplification.

Tiss very rare to find a demo of a pedal running through an average SS amplifier using an average guitar. 8|

The Laney Amplifier in that picture is a 3 channel Keyboard amp and although I've done some modifications the circuit is still very basic, only has bass and treble and a gain for each input. So whatever magic is present in the sound is from the pedal board circuitry as the Laney is really quite dull on it's own. The Laney does have tank reverb which is a handy extra. I doubt there is any secret agent mojo circuitry involved just a combination of a few known circuits that when used in the right way make the magic.

The first pedal is a simple Fet circuit I made up and if there is any mojo it's because the treble and bass only CUT, no boost. So tone controls on 10 equals flat response. this pedal is nearly always on and in conjunction with the Mictester compressor it gives the classic rock roll rattle.

The Tweed57 is way too hot, too much of everything, In time it will go.
The Boss OS2 is interesting and I use it to get the darker dirt sounds.
 Chorus/Delay,,, need no explanation.

Next comes the Compressor/OD/Cabsim,, The ugly home made black box.
I call it my Cruise Control board,  :)
This 3 part setup runs on 18VDC and that does help quite a bit.

With just the right amount of clean boost from the First pedal the compressor works very similar to some of the old classic Valve rigs I used as a lad. If the input signal is way too big the compressor will jack up a bit and the bass will fart,, but then a lot of classic valve rig do the same thing.  8|

There is an extra diode clipper in between the Comp and Cab sim,, still not sure if it's really needed. The cab sim is based on an old Nobels unit from the 70's then a master volume with a level shift added to give a CLEAN volume boost for the times when your lead bit has to get above a mad drummer.
Then my super simple PhAbbTone circuit.
Depending on the venue,, I do add a graphic EQ and plug in an extra speaker to give the bottom end a bit more grunt in larger gigs.
Cheers, Phil.

 

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