Skip to content

a blog on effects

Menu
  • Home
  • collection (486)
  • Ibanez (111)
  • Danelectro (53)
  • DOD, Digitech (51)
  • Electro-Harmonix (40)
  • Boss (54)
  • Other Brands (177)
Menu

Korg TNB-1 Tone Booster

Posted on 9/05/201413/07/2016 by mirosol

Korg-TNB1

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…

Korg-TNB1-guts1

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.

Korg-TNB1-guts2

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.

Korg-TNB1-guts3

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.

2 thoughts on “Korg TNB-1 Tone Booster”

  1. Pepe says:
    12/07/2016 at 15:50

    Very nice review of the TNB-1! It is really a cool sounding unit with a great distortion sound. I received my own TNB-1 a few weeks ago and I love it.

    The original circuits have in fact been developed by KORG. KORG used to name the boards KLM-xxx since 1977 or 1978 and they can be found in their synthesizers and effects up till today. KLM is definitely KORG. So the whole effects series and the PME-40X series (which I love to pieces) are made by KORG and Yamaha was allowed to distribute them under their own flag. In return KORG was allowed to use Yamaha technology in their synthesizers. This symbiosis went on till the end of the ’80s when KORG was finally financially independent due to the big success with the KORG M1 workstation. But that’s a completely different story.

    All in all the old analog KORG pedals are awesome. I tried a few of these and they didn’t disappoint me at all. Even the Parametric EQ is not just a tone tool – it’s capable of creating interesting sounds like cocked wah.

    Reply
    1. mirosol says:
      13/07/2016 at 08:22

      Cool! I was not aware who OEM’d who, so this input is very welcome! Thanks. I’ll update the text part accordingly…
      +m

      Reply

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

/usr/bin/locate

/usr/bin/whoami

here used to be a short description of me. however, it wasn't exactly accurate anymore. so i'm replacing it with this placeholder for now. and yes. it's been a long time since my last post. but let me assure you. i'm very much still alive.

Found an error? One of my assumptions is dead wrong? Something else is just not right? Let me know! Leave a comment to a post, or drop a line to mirosol at kapsi dot fi.

I do mods, repairs and custom builds too. For inquiries, use the email address above.

/var/lib/collection

  • Electro-Harmonix (40)
  • DOD, Digitech (51)
  • Other Brands (177)
  • Boss (54)
  • Danelectro (53)
  • Ibanez (111)

/var/lib/tags

Amp Autowah Bass Boost Booster Chorus Compressor Delay Distortion Echo Envelope Filter EQ Filter Flanger Fuzz Harmony Loop Modulation Noise Gate Octave Overdrive Phaser Pitch Power Preamp Reverb Special/Multi Synthesizer Tremolo Tuner Utility Vibe Vibrato Wah

/usr/lib/comments_recent

  • zix on DOD FX55-B Supra Distortion
  • Ali Imran on Ibanez MF5 Modern Fusion
  • Ali Imran on Ibanez MF5 Modern Fusion
  • Schlunzo on Ibanez MS10 Metal Charger
  • Jefferson on Ibanez MS10 Metal Charger

/var/lib/archives

  • August 2016
  • July 2016
  • June 2016
  • September 2015
  • June 2015
  • May 2015
  • April 2015
  • March 2015
  • February 2015
  • January 2015
  • December 2014
  • November 2014
  • October 2014
  • September 2014
  • August 2014
  • July 2014
  • June 2014
  • May 2014
  • April 2014
  • March 2014
  • February 2014
  • January 2014
  • December 2013
  • November 2013
  • October 2013
  • September 2013
  • August 2013
  • July 2013
© 2025 | Powered by Superbs Personal Blog theme