Posts Tagged ‘Booster’

Greg Fryer Brian May Signature Treble Booster Touring

Friday, July 15th, 2016


What is it?
Greg Fryer Brian May Signature Treble Booster Touring. Monster named unit that’s made most likely in th UK around 2010.

Don’t know where to begin. Got one of these in a trade and figured that i needed to have one, just to know what it’s all about. Sometimes i tend to look outside the box, but this is something that just doesn’t make all that much sense to me. Fryer guitars/amps/electronics is an UK brand that’s goal has been reproducing the Queen guitar tone since its formation in 2008. Mr. May is obvious idol for many for his high technical skill with guitar. I’ve listened to my share of Queen back in the day, so i’m quite happy that i don’t have to do so anymore. But then.. So a company based on marketing tools that can recreate this one guy’s tone? Sure. Why not. At least there seems to be a market and people to buy effect units, amps and guitars that’ll help them sound like mr. May. The original DIY amp that was used back in the day has been well documented and it’ll need a treble booster to make it distort per May’s tone. After all, it is just a ~0,75 watt germanium transistor loaded amplifier that runs on a single 9V battery. And since reissue and of the amp and a DIY kit of it were apparently a hit, there was a need to create suitable treble boosters for all the thousands of home guitarists chasing that May tone. There is some more info on Knight Audio Technologies page. And as the die hard May fans already know, i’m focusing on the factory made version(s), not the custom build original that mr. Fryer built for mr. May. The amp called Deacy amp and treble boosters are all listed at KAT store, with a bit more information that i can give. Anyway. There are three different boosters in this series, “Plus”, “Deluxe” and “Touring”. So far i’ve only seen a traced schematic for the Deluxe verion, but i believe these three are just voiced slightly differently between each other. And KAT shop descriptions agree with my assumption.


The box has an input jack, output jack and a battery door. That’s it – all three versions are the same. Which makes me believe all three also share the PCB and contruction with the other versions. For the trace, you could head over to Paul’s page at There you’ll find a schematic for the Deluxe version. Does it surprise anyone when the schematic shows a slightly modified Rangemaster? Probably not. But the real surprise comes when we check the board inside the unit.


Yup. That’s goop. And reason to goop a Rangemaster clone? Seriously, i can’t come up with one. Trying to hide the fact that is is a Rangemaster without gain control? It is still just a single transistor treble booster that works in manner of dropping the lower frequencies and amplifying the treble content to a single transistor’s capabilities. As a gooped unit with such low feature list, i think it’s the best if we just move on.

How does it sound?
Like a treble booster. Kills your bottom and makes your guitar screech and scream. I have no access to Deacy amp or anything like it, so i can’t take a sip of the intended sound. As a standalone treble booster, this has a few advatages. Like the zeroconf. But then again, this feature has huge disadvantages as well. As is, this can only be used as always on unit, which i believe doesn’t suit that many guitarists. Think about it. You’ll spend a $1000€ on a guitar that has a sound that suits your preference, another $1000€ on an amp that, again, has a sound that suits your preference. Now, you take a $150€ treble booster that will discard most of the tone that your guitar and amp are capable of. And on top of this, you’ll be hooked on batteries for life. The current draw is minimal, but still. You’ll need to swap the battery at least before every gig so it won’t fail on you. I’d get the idea if this was presented as a basic stomp box which could be used on demand for leads and so on. Sure you can do that with a effects looper. But that’ll be still quite stupid idea as you get 5 EHX screaming birds for the price of one of these. You’ll really need to be in to May’s tone to even consider getting one of these.

EHX The Mole Nano

Friday, January 30th, 2015


What is it?
Electro-Harmonix The Mole Bass Booster from Nano series. Made in NYC in 2013.

As the one transistor, simple boosters in the EHX family go, here we have the “Bass Booster”. Circuit has pretty much the same topology as all the other simple boosters (LPB-1 and Screaming Bird). The component values are the ones that determine the frequency response and thus, determine if the circuit boost full-range, bass or treble. On full-range, we cut nothing out. On bass, we cut out the high. On treble we cut out the bass. Simple, isn’t it. I was expecting to see the same board as for LPB-1, but no. The Mole has its own design, even though the circuit is still simple, one transistor booster.


Here we have our modern EHX board with most of the design laid out in SMD, while couple of the caps are through hole. And the transistor is a classic TO-92 packaged device too. BC550C. I think EHX has bought those to last a lifetime. At least this type seems to be the weapon of choice for most EHX pedals calling for NPN transistors. Overall, simple and useful. Why?

How does it sound?
Useful due to how it sounds. Want to cut the high end off and give some volume for the lows? For very cheap nano series pedal, this is the way to go. While i don’t see myself using this on my main board anytime soon, i think of the unit as a tool to shape the tones in studio sessions. While it is very good unit, the lows tend to need a lot more power to get amplified. You know, your 50W all tube guitar amp will be louder than your 100W all tube bass amp. In reality, this isn’t exactly true, but due to how we humans perceive frequencies, it might as well be. Due to this, the Mole seems a bit sluggish for its output level, when compared to LPB-1 and Screaming Bird. It could be louder, but still. This one gives you decent kick for your lows while cutting the top end. Usable. Tool.

Ibanez BB9 Bottom Booster

Wednesday, September 3rd, 2014


What is it?
Ibanez BB9 Bottom Booster, from modern 9-series. Made in china around 2010 or so.

There are only a few Ibanez designs that are more like meh. This is definitely not one of those. I had interest for this for some time, before i spotted one for reasonable price tag on one auction site. This particular unit was apparently a demo unit for some store. Very little wear and nice near mint condition with original  box and papers. Played with this for quite some time once i received it. There is a beautiful traced schematic up at Dirk’s page, so there were no rush in seeing how it is made. Reason for opening it wasn’t as usual as for most pedals.

That reason being a small mishap on the studio floor. I had just recorded all base guitars for 11 tracks of 12 for the album we were doing. I thought i needed to add a bit of reverb for the other effect line. I took my previously repaired Boss RV-2 out of the bag and chained it with all the other pedal in that chain. This resulted in nothing more but a hiss. Something went terribly wrong and my BB9 was dead. I figured it had to be some sort of power surge, but since i (obviously) didn’t have suitable tools or spare parts with me, i had to make due with other solutions for the second effect line on the last track.


Once the unit was back at my desk, the fault was easy to track down. No power. This is where Dirk’s schematic came in really handy. Don’t know how that surge occurred, but it burned the DC-DC converter (a.k.a. charge pump) chip. As you can see in the (crappy) photo below, the chip on top left is socketed. I almost never use sockets for anything, but since the charge pump on this one *can* die, i figured it’s best to have it socketed. After swapping the chip and polarity protection diode as a precaution, the box rocks again.


To get going on this post, the design of the BB9 is solid Maxon quality with modern board design and manufacturing method. If you checked the schematic linked above, you’ll see a power supply section that creates a bipolar +9/-9 volt swing with LT1044 DC-DC converter. This means that the pedal runs actually on 18 volts, using ground’s zero volts as a reference voltage.  For me and my fix, i only had ICL7660S chips at hand, but these are pin-to-pin equivalent and they can be used as a drop-in replacement for each other.

On the topology, is one half of JRC4558 acting as input buffer. Then we have dual gang potentiometer setting the level of signal passed to gain recovery and the actual gain of the clipping amp that is paired with a static gyrator that sets the boosted frequencies. After these we have active tone control to have nice control over the treble content. This leads to level control and output. Not too conventional way to create overdriven boost.


What comes to box design, it surely ain’t as aesthetic as the 30 year older 9-serie units. It isn’t ugly though. Sort of reminds me a bit of build methods we can find in Marshall small metal series pedals. Pedal follows the original series on the enclosure and carbon film resistors, but not much else. Here we have four separate boards to ease the manual labor. Neat and beautiful on the outside, but pretty dull on the inside – except for the circuit design.

How does it sound?
So good that no words are enough to match it. BB9 offers mild overdrive tones with really, really good sounding frequency response. It is not a distortion nor a classic overdrive in sense of tubescreamers or others, but something that brings your tube amp alive in a manner that can only be matched by few others. Also, it’s not a clean booster. It is a pedal that will give out better, no matter how subjective that term is, overall tone. Little bit of grit and boost combined. Even the voltage swing has a strong emotion-like feeling of great amount of available headroom. This is definitely one of the greatest sounding Ibanez branded boxes. Ever.

EHX Nano LPB-1 Linear Power Booster

Saturday, July 26th, 2014


What is it?
Electro-Harmonix LPB-1 Linear Power Booster from EHX Nano series. Made in US in 00’s.

I’ve been over this units grandfather before in the form of EGO Microphone Booster. In its heart it is still the same simple one-transistor-as-amplifier booster. The base topology remains, even there are a number of modern additions to the box. First off, the bypass method is per modern standard, meaning a 3PDT stomp switch with true bypass. There are power filtering and polarity protection present and chokes for input and output. The tiny, simple circuit can now be powered by modern standard power supply or a battery. Board layout is really ugly and there’s acres of wasteland in there.


I had a conversation with one person who was looking for plain volume boost for his setup and asked me what he should do about it. Get a custom build from me or try some commercial solution? Or some other option? I said “i think the best way to see if a simple booster is what you want, is to buy a LPB-1 as used unit”. You know, since you can get one for 25€ post-paid. I also said that if it didn’t suit him, i’d buy it off from him with that price. And here we are. I wasn’t planning on buying one, but i guess it’s good to have one of these too. and now the dude knows that he can’t get pure, clean power amp volume boost out of any pedal. He’ll need an amp that can do that.

How does it sound?
Like a single transistor booster. Clever and nice way to get your vintage-style single coils to light up. Some might even use this as a boos for clean lead sounds. But still i’d recommend this only for single coil pickups with lowish output. Ive been playing around with these circuits over the years, but once i got this unit.. I though it was broken. On any setting over unity level, it started to break up the sound in not so great manner. I checked the unit over and it was (still is) fine. I took another guitar and, yup. The super high output Hagström customs were just too much for it. The distortion created by too high input level isn’t pleasing.

Overall tone? Clean, colorless, tasteless, odorless simple boost. A tool.

Korg TNB-1 Tone Booster

Friday, May 9th, 2014


What is it?
Korg TNB-1 Tone Booster from Series 1. Made in japan in late 80’s.

Korg hasn’t produced many guitar effects, but they are well known for their high quality synthesizers and other products. In fact, the Series 1 is just a rebranded Yamaha 01 series, both manufactured by KLM. Or the Yamaha series may by simply a rebrnaded Korg series. Hard to say, but to me it seems like KLM may have been offering various designs as OEM boxes for more than just two brands. Of this i’m not sure, but the designs show a lot of resemblance to those Pearl effects. All the way to the enclosure design… (Nope! “KLM” means the board is designed and built by Korg Japan, the other manifestations of the KLM circuits in other brand pedals are OEM’d Korgs. This was just brought to my attention and i was not aware of this before, thanks to Pepe!) Got this one in near mint condition and with original box. And for a good price, so i couldn’t let it go. I had studied the schematic earlier on and this seemed like a great preamp/distortion box. Schematic has “KLM690” printed on it. I’d be rather interested to know what other brands have bought OEM designs from that company…


Really solid enclosure that is fastened through the top rather than from bottom. Relatively small board footprint and comes with dreadful asymmetry. Despite that, i think i’m just going to go with saying that the unit is very well designed and built. It’s not offering any high gloss eye candy on the board design, but i think it should handle heavy use for a long time.


To analyze the schematic, there is input buffer that splits the signal for bypass buffer and the first driver stage. The bypass buffrer outputs to DPDT stomp switch and while it has two buffers on in bypass mode, i didn’t notice any of the sucking. With a short testing, that is. Anyway. The first driver stage is non-inverting opamp stage that has similar gain control that you’ll find in OD250/Dist+, only with 1M reverse log pot. This should give out more usable sweep for the pot and it does. This gain stage can be cranked to massive distortion. The stage drives a simple two band tone control which then passes the signal to recovery gain stage and volume control. I’d say the original designer has put the TL072 in good use. The recovery gain stage is inverting, so the wave coming out is inverted. This is not unusual, but something that user might want or need to know.


I find the bypass method interesting. Simple but effective. While the bypass buffer always gets the signal in, its output is switched between effect and bypass. Other pole of that switch either kills the gain stage or lights up the LED. It may not be anything super special, but it has some out of the box thinking involved. This is a very nice unit to have.

How does it sound?
From mild preamp to massive distortion with well working EQ section. Good ouput level and usable range from unity tone shaper to singing leads. It sounds good. No denying that. I’d still call this an distortion rather than a conventional booster, it offers nice versatility in tone. Good sounding well built unit. I do not see any downsides to this one.

Electro Harmonix Ego Microphone Booster

Sunday, March 9th, 2014

Guess i haven’t been this deep into producing vintage pedal porn before…


What is it?
Electro Harmonix Ego Microphone Booster. Made in US around 1969, according to pot labels.

Got this unit as a defunct gift from J. Stolpe of Väinö Grön (and numerous other bands/musical outfits). Story is the he found this unit from his father’s belongings and kept it. As we got into talks about my favourite subject in the world, he just decided to give it to me. The signal was passing on “bypass” mode and when the battery was connected and the boost engaged it acted as a dirty buffer. After looking into the design, it became clear that the design is 1:1 with all the original LPB-1s and 2s. All it takes to create a one transistor boost is an input cap, two resistors from supply to base and base to ground (these two form a bias voltage for the transistor), gain setting resistor from emitter to ground and a resistor from supply to the collector. Oh. And a output cap. Boost control is your standard 100K pot (output cap to lug 3, lug 1 to ground and lug 2 is your output). By the way, Beavisaudio has a perfect one paged article/image about how the single transistor booster works. If you’re not familiar with the subject, check it out here.


The fault in this unit was with the resistor from transistor emitter to ground. It was completely burned out and cut in two. Looked like someone had already tried to fix it with not so great results. I was afraid that the 36999 branded transistor was dead due to the heat. Those transistors are  apparently Fairchild made clones of 2N5088, that they manufactured for EHX in late 60s. I have no way of verifying this information, but it was on the internet, so it *must* be true.

Anyway. The burned resistor seemed like 330R in value, so i went through all my boxes and drawers for similar carbon composition resistor to match the original. Nope. I didn’t have any. So i just fixed it, no matter of the cost. As you can see in the photo above, there’s one resistor that doesn’t quite match the others. I used the standard 1/6W 1% metal film resistor in its place. Works. And even the original transistor works perfectly!

Then i thought to myself, “what makes this a microphone booster, as the circuit is 1:1 with Linear Power Booster?” The jacks. That must be it. The LPB has the other end as a plug – you know, to be used with a guitar. If there are two jacks, then it must be for the microphone. Damn i just love vintage stuff like this!

How does it sound?
Exactly like the linear power booster(s). Clean and loudish  to the ~90% of the knob sweep. And then badly distorting at the end. The circuit keeps the frequencies well in tact while the line driving capabilities are worth a mention. Not great thing, but very cool little tool to have. In fact, i’d recommend every guitarist to use one of the LPB-1s in their lifetime. It should at least open ones eyes to the idea behind loud “clean” boosters.