Build Reports

Showing 9 build reports for the L5 Preamp project. Submit yours →

CHITO
Score:
9

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MOTHER OF ALL PEDALS

Project: L5 Preamp

Build description

ALL PARTS: HQ & all purchased from Mouser & Small Bear Electronics based on the Aion supplied BOM

OpAmps & ICs: OPA2134, OPA134, LM741P, CA3080

I was able to buy the 16mm 2.5KA Alpha pots from a UK distributor from a link supplied by Aion. Pots were not the right angle type though. I wired both of ’em to the PCB.

It took me a number of weeks to carefully sort parts, measure the values & populate the board. I had to wait for 3 back ordered items from Mouser for a long time but just in time when the Aion enclosure was ready to order. I had to buy a same size & value box cap (0.0082uF) & install ‘em while waiting for the last backordered cap so I could test the “Mother of All Pedals”. I’ll change those in a later time.

I used a shielded wire for the IN, OUT & LED pads / additional ground pads. I also added the experimental (100K) resistors for the off-board switches. It made the Channel switching very quiet although I could still hear a little bit of pop noise when the Bypass Mode switch is engaged/disengaged. I opted for the quieter Always On LED operation. On the other hand, the Bypass-Off LED operation confuses me because the 3 LEDs on the offboard switches don’t turn off at all and a loud pop is always present in spite of the experimental resistors.

Using the Signal Generator app on my iPhone 6 yielded mixed & inaccurate voltages so I used the ToneGenerator app instead but measuring the required 1kHz 30mV sine wave with a multimeter was hard to achieve. So, I just connected the iPhone output directly to the test points and adjusted the Distortion trimpot to 4.4VAC which was easily and accurately achieved. I know this isn’t the right way but it was my last resort.

TESTING EQUIPMENTS: Marshall JVM 205H head / Marshall 1960A cab / Fender Metalhead Amp & cab / IBANEZ S5470Q guitar. Jackson Japan-made Warrior guitar with genuine SD Invader humbuckers. Only Lab Series is connected — to the power amp input and alternately used as a pedal.

TEST RESULTS: A very quiet preamp for me as long as it’s used on an equally quiet power amp or is used as a pedal & connected to the front of a regular amp. The compressor / limiter & the distortion works fine for my rig. The 2 Channel tones sound great! Lots of headroom & very tweakable!

Thanks to Kevin for resurrecting the great Lab Series L5 Preamp amazingly reduced to Lilliputian specs.

Are you tired of carrying heavy rig to your gigs? Try the Mother of All Pedals, hook it up to the PA and tell us all about it……… Gulliver!

James Pearson
Score:
8

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Lab Series L5 Preamp

Project: L5 Preamp

Build description

This went together well, a faux pas on my part led to some fault finding. Trying to save some cash I ordered the parts in the UK so i ended up with larger resistors (physical size) than i would have liked. having said that there was no problem fitting them just does not look as neat, I have had trouble getting the channel switches to link with the bypass so I ended up sacking it off and having them on during bypass mode. all in all being that this is the most complex project i have undertaken i have learnt a load and the end result is superb.

I am lucky to have a friend who owns a metal fabrication shop who also happens to be into guitars, I made him a Refactor in return for the odd bit of painting and such. so I managed to get the enclosure painted and laser etched using the graphics from the project.

Modifications or part substitutions

The only modification i had to undertake was altering the frequency pot by flipping the wafers.

Score:
8

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LAB preamp

Project: L5 Preamp

Build description

I’m not new to a soldering iron, but this is the first pedal I’ve ever completed. Went together relatively smoothly, though I had buy a second enclosure after screwing the first one up. I’m having trouble getting the channel select LED’s to function properly, otherwise everything works wonderfully. Calibration was easy with an iPhone 6 (my volume/ gain settings matched those in the instructions exactly). I built the LAB pedal to ensure I could get a nice tone out of any backline amp when I travel. It really wakes up my Ampeg R-15-R; I’m excited to try it out on other setups/ instruments. I anticipate that I’ll be able to get rid of my compressor, eq, and one overdrive pedal now, because this one does it all better. I’I also drew a dog on it.

Modifications or part substitutions

Multicolor knobs, yellow bypass LED.

Mike @ Blackoctopuspedalworx
Score:
5

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Aion L5

Project: L5 Preamp
Variant: Stock.

Build description

Build materials: Xicon 1% MFR, Mainly 5% WIMA caps with a few 5%TDK/Epcos scattered in and a lone 5% Kemet. Nichicon Fine Gold electros in the signal path and other Nichicon in the power supply. TDK 5% (C0G) MLCC’s. Gold plated pin/socket IC sockets. Mainly TI IC’s. Mostly Alpha pots and Bourns trims. Kobiconn power jack an switchcraft enclosed guitar jacks.

Had to modify some pots for difficult to find values. Missing the nameplate, I will have to find one of those.

Score:
4

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All Modes Are Beast Modes

Project: L5 Preamp

Build description

This was one of the cleanest, most well thought out “big” projects I’ve ever built, and I come from the synth DIY world so I’ve seen some properly big ones! Kudos, Kevin. Fantastic work.

Everything worked perfectly at the first power-up aside from the bypass LED, which stayed lit no matter what state the bypass switch was in. 2 minutes of web searching yielded the answer – don’t connect the two switch boards together with the wire as shown in the diagram, just run one from the mode switch PCB to its own ground on the main board. (Maybe that’s in the docs?)

I’m a modular synthesizer manufacturer, not a guitarist, so I could only test it on the Eurorack, but I’m happy to report that it sounds just as fantastic on synths as it does on guitar. Time to build the second one, which I’m absolutely keeping for myself. =)

Modifications or part substitutions

None. I like faithful recreations to be as faithful as possible. I had almost all of the parts in stock but the few that needed to be ordered were available straight out of the BOM.

Nicko J.
Score:
2

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Most Meticulous DIY yet!

Project: L5 Preamp

Build description

Took me almost a day finishing this one out, of course not just in one sitting. Some pots came from different vendors so I had to improvise making: (1) dust seals using heatshrink tube and electrical tape, and (2) PCB mount pins using diode clipped leads. I used male header pins on the 15V and IC10 tests, makes the calibration a breeze. I put sockets for all the semiconductors just to be safe. Using my Sony Xperia XA phone the sound level fell around -10 dB to -11 dB to produce 30mV. Initially I used clear blue LED for the compressor indicator but noticed that it lit drastically and was on all the time, even when the comp was off. Switching back to the recommended red LED fixed it. Set the comp trimmer at minimum. This project is intended for the experienced pedal builder. You have to be very meticulous on each part before soldering them on. Glad to be part of the Aion mailing list and be able to make it on his early bird pre-order list. Hats off to Kevin for making great stuff. Keep ’em coming!

Modifications or part substitutions

VOL1 to 2kA
MID1 to 2kA
IC4-IC9, and IC12 to OPA2134
C51-C65 to 220uF, 50V
C40 to 2u2 tantalum

digi2t
Score:
17

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LAB Series L5 preamp.

Project: L5 Preamp

Build description

Finally got it done! Like the project docs states, it’s not the cheapest build, but it is one of my best. I highly recommend it. Each channel has it’s own character, it’s like having two different amps, all at the touch of a footswitch. The tone stack is very interactive with the Multifilter and/or the Frequency control, making it fairly difficult not to be able to dial in a tone. I used a signal generator for the tuning, and dialed in the compressor to the 1.7v as per the original. I find that what ever volume setting I use, I have plenty of range through the sweep to make the compressor an effective tool.

Modifications or part substitutions

I ended up using OPA134’s in IC1, IC2, and IC13 positions, and TL072 for the rest of the opamps. I found that channel 1 offered up a bit more chime, and channel 2 more harmonic artifacts on the decay with these chips. As for the 2.7uF tantalum cap, here’s a trick; use a 2.2uF, and a 0.47uF in parallel. These values are much more readily available, and cheaper too. Also, more of a chance that you’ll use these values in other projects. Wrap the leads of the 0.47uF to the 2.2uF leads, and touch with solder. Clip the 0.47 leads, drop the 2.2 leads into the board, and solder the 2.2 leads. Auditioning a few through my capacitance meter, this combo gave me exactly 2.7uF. Even with tolerance swing, you’ll be right in the wheelhouse. Look at my pictures, you’ll see the yellow and green caps sitting side by side. There’s plenty of room for this arrangement.

MikeA
Score:
0

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Complex, but well worth the time!

Project: L5 Preamp
Variant: Stock with substitutions

Build description

This is the most complex DIY guitar pedal PCB I’ve seen, but the build is well worth the effort. Design, layout and documentation is top-notch, and the quality of the PCB and enclosure are excellent. Thanks to Kevin for his outstanding work on this project.

I used the Aion PCB, enclosure, name plate and parts list, all stock except as noted below. Kevin’s listed sources were all good, even for the hard-to-find 2.5kA pots.

I tried subbing a NE 5534AP for IC1 (the LF356N) but it was not compatible, CH 2 levels fell off and distorted after about 2:00 on the Vol2 knob. I replaced it with an OPA134 in IC1 and that sounded great. I also subbed NJM 2068DD for all the RC 4558P IC’s and the noise floor is very good for a circuit with this amount of gain.

I liked the sound of a cap in place of the CX1 jumper in the Channel 1 tone stack. To my ear CH1 was a little bass-heavy with the jumper, and modeling it with the Duncan Tonestack Calc app showed a nice curve with an 80 to 100nF cap in that position.

I made current-limiting resistor substitutions (RX5-6) based on current calculations for low-current waterclear LEDs, followed by some final adjustments for taste.

I had some higher-voltage-rated 400x diodes on hand with the same forward voltage as the 4004, so I used those on the power input side. I matched the Vf of the symmetrical pairs as closely as possible (D6 with D9, D7 with D8) just for fun.

With a 10.1V AC power supply, measured current draw is:
CH1 active: 365mA with load resistors, 315mA without
CH2 active: 370mA with load resistors, 322mA without

I may swap out the DC jack for one with a 2.5mm center pin to match my pedalboard’s TrueTone CS-12 9VAC supply cable (the DC supply cables are 2.1mm.) I’m not sure whether the Alesis 9VAC power supply has a 2.5mm connector as well, but I’ve ordered one for portability when I’m not using my pedal board.

I set the Distortion trim pot for the recommended 4.4V, and the Compressor trim pot fully CCW which reads about 450mV on output. The recommended 1.17V output for the Comp calibration required the trim pot to be fully CW and needed an excessively high input signal to trigger the compressor.

Again, this is a great project for the experienced builder, and I recommend it highly!

Modifications or part substitutions

IC1: TI OPA134
IC4-IC9, IC12: NJM 2068DD
CX1: 82nF (80 to 100 sounded good)
D1, D2: 1N4006
D4, D5: 1N4448
D6-D9: 1N4005
RX5, RX6: 47k to accommodate bright low-current LEDs for CH1/CH2/Bypass
RX7-RX9: 5M which keep these 3 LEDs barely unlit in the “off” state
Removed load resistors RX3-RX4 after initial testing to reduce current requirement

Del Pedro
Score:
0

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Lab Series Preamp

Project: L5 Preamp

Build description

Here is my Lab Series Preamp. Obviously PCB, enclosure and nameplate are from Aion.
IMO it both sounds and looks good. I think the preamp sounds ok in front of an amp. But I definitely prefer it with a power amp. Nice clean sounds and the distortions sounds quite tube like. I especially like channel 1 with a booster in front.
To be honest I still prefer my tube amps but the Lab Series Preamp really does sound good.

The compressor works as expected. But I don’t like that it is located after the master volume. So you need quite different settings wether you use the preamp in front of an amp or with a power amp. ‘comp trim’ helps a little bit but does not do very much. But you can’t blame Aion as that’s how Moog designed the amp.

Modifications or part substitutions

I used my own parts.

I had quite some trouble to get the preamp running reliably.
I had problems with the power supply. Without op-amps the voltages were fine. But with op-amps the +15V voltage dropped to -0.7V most of the time. This was a ‘latch-up’ error. I fixed it with two 1N4001 diodes at the output of the voltage regulators (parallel to RX3 and RX4). See the datasheets of the voltage regulators or have a look at the picture of my preamp.
I also added two 1 Ohm (2W) resistors to the power jack to drop the voltage a little bit. This dropped the voltage at the input of the voltage regulators from 25V to 19V. So the regulators don’t get as hot.

Then I had lots of problems to find a combination of ICs that work. I strongly recommend to not replace all RC4558s with NE5532s or OPA2134s! I did this a had several problems:
– distortion in channel 2 sounded really bad
– gate like effect in channel 2 when mids where cut
– extremely bad sound of the compressor with high input
When the last two problems occured you could see high frequency oscillation on the oscilloscope.

I finally found a combination of IC that works for me:
IC1: OPA134
IC2: OPA134
IC4: RC4558
IC5: RC4558
IC6: RC4558
IC7: RC4558
IC8: RC4558
IC9: NE5532
IC10: CA3080
IC11: CA3080
IC12: NE5532
IC13: OPA134