#nutube

[mesotokyo]

FET＋Nutube多段増幅オーバードライブペダルを作った

だいぶ設計に時間を費やしてしまったひずみ系エフェクターペダル制作の話です。今の自分のエフェクター制作スキルが100％反映されたペダルと言っても過言ではありません。ということで中身の紹介です。

過去にもたびたび取り上げているKORGの小型真空管「Nutube」ですが、ある程度自分にノウハウが貯まってきたので、それを形にした現時点での自分的決定版エフェクターペダルを作ることにしました。

基本設計は以前試作したものに近いですが、そちらの不満点をすべて改善して、さらにプラスアルファの機能を加えています。具体的には、

ON/OFF切り替え時のポップノイズ削減のため入出力段にカップリングコンデンサを追加

ポップノイズ削減と非可聴域での発振防止のため入力段に超高域をカットするローパスフィルタを追加

GAINツマミを8～9時あたりに絞った際にはFET差動増幅回路部分で歪まないようNutubeよりも前の増幅段のゲインを調整

ミックス可能なローカット/ハイカット（＝ハイパス/ローパス）フィルタを追加

原音をミックスできるDry Mix機能

といった改善が加わっています。

ブロック図

こちらが今回作成したペダルのブロック図です。トゥルーバイパス仕様なので、ON/OFF切り替えスイッチ周りのブロックは省略しています。

入力された信号はトランジスタバッファを通ったあと、GAINツマミでレベル調整されたうえでゲイン20倍のオペアンプ増幅回路で増幅されます。続いてFETを使った差動増幅回路でさらに信号を増幅するとともに、原音と位相が同じ信号と位相が反転した信号の2つを作ります。この2つの信号をそれぞれNutubeで個別に増幅��た後、オペアンプによる差動増幅回路に入力して信号をミックスし、その後フィルタを通した信号とミックスしたうえでトランジスタバッファを通した信号を出力します。

電源周りとしては、入力電源はペダル型エフェクターで一般的な9Vですが、内部的に昇圧回路を組み込んで±12Vを生成しています。さらに、FET増幅回路向けに-12Vを分圧して-10Vのバイアス電圧も生成し、オペアンプ回路の電源は±12V、FET増幅回路では-10/+12V、Nutube増幅回路では+12/0Vと異なる電圧を供給することで、各増幅段での歪む/歪まないをコントロールしています。歪み方としては、おおむねGAINツマミが7～9時くらいでほぼ歪みなし、9～12時くらいでNutubeでの歪み、12～5時くらいではFETでの歪み＋Nutubeでの歪みが起こる感じになります。

トーン回路

歪み系ペダルで歪み回路と同じくらい重要なのが、トーンでの色付けです。どのあたりの周波数帯をどのくらいカット・ブーストするかだけでなく、操作性も重要な要素です。ツマミを増やして設定できるパラメータを増やせば柔軟性は増えますが、その分筐体も大きくなります。さらに、パラメータは多いのに「使える音」の範囲は狭い（その分無駄な設定が増えてしまう）、といったことも発生する可能性があります。今回はそもそものコンセプトとしてペダル型にこだわっていたので、トーン回路で使用するツマミは1つか2つという縛りを設けたうえで設計に入りました。

一般的なギター用歪み系ペダルでは低音域を大きくカットするものも多いですが、本ペダルはギター/ベース両方での使用を想定しているため、低域をカットしない設定も必須としました。この条件で思いついたのが、DOEPFERのアナログシンセ（DARK ENERGY Ⅱ）で使用されている可変型のマルチモードフィルタです。このシンセのフィルタはハイパスフィルタ/ノッチフィルタ/ハイパスフィルタ/ノッチフィルタの間で特性を連続的にツマミで変えることができる仕様で、これは複数のフィルタの出力をミックスすることで実現しています。これにインスパイアされ、特性をローパスフィルタとハイパスフィルタの間で連続的に可変できるフィルタを設計しました。カットオフ周波数はローパスフィルタ（ハイカットフィルタ）側が876Hz、ハイパスフィルタ（ローカットフィルタ）側が232Hzで、それぞれQを2.75、3.42と高めに設定することで、カットオフ周波数近辺の信号を軽く持ち上げたあとにそれ以上/以下の信号をカットする形にしています。

今回採用したローパスフィルタ/ハイパスフィルタはカット量が固定のタイプなので、フィルタを通していない音とミックスすることでカット量を調整できるようにしています。また、スイッチ切り替えで原音とフィルタを通した音をミックスできるようにもしています。

回路図

メインの回路図は次のようになっています。電源部（昇圧回路）については省略していますが、これは別基板に分けて電源部だけあとで入れ替えられるようにするためです。

NC（接続無し）や0Ωの抵抗/コンデンサは後日信号経路を切り替えられるようにするために設定しています（実際、後日の調整でC24には1uFのコンデンサを、C3はショートさせてC21を外す設定にしています）。

なお、Nutubeのヒーター部にはデフォルトでは9V入力電圧を（電源の逆接続防止ダイオードを介して）そのまま供給していますが、この場合出力電圧の高いACアダプタなどを間違って接続してしまった場合にヒーターが切れてしまうおそれがあります。そのため、必要に応��てツェナーダイオードやヒューズなどを使った過電圧保護回路などを別途設置したほうがよさそうです。

基板設計

トーン回路の追加によって部品点数が増加していることから、小型ケースに収めるためにプリント基板を設計します（不器用なので配線の手間を下げたいというのも理由の1つです）。ただ、本ペダルは機械的な部品だけでもツマミ4つ＋入出力ジャック＋電源ジャック＋ON/OFFスイッチ（プッシュスイッチ）＋Mix切り替えスイッチが必要で、これだけでもそれなりの面積となります。さらに、Nutubeのサイズも無視できません。試行錯誤しましたが自作エフェクターで一般的なBサイズ（60×110×30mmサイズ）に収めることは困難という結論となったため、それより一回り大きいN1サイズ（66mm×121mm×40mmサイズ）のケースを使うことにしました。

さらに、穴あけ加工の手間を減らすため、各種ジャックやスイッチ、ツマミ類をすべて上面に取り付ける形にしました（後述）。

最終的なプリント基板は次のようになっています。

ケース加工

プリント基板の発注から納品まで10日ほどがかかるので、そのあいだにケースの加工をします。部品はすべてペダルの表面だけに実装するので、ケースの裏ブタに穴あけをしました（つまり一般的なペダルとはケースが上下逆になる）。ここではケースの裏ブタに穴あけをしましたが、このやり方の大きなメリットとしてそれなりの厚みがある金属板・樹脂版を天板として使うことができるという点があります。つまり、ホームセンターで適当な金属板を購入して加工サービス等で加工してもらったり、プリント基板製造サービスで穴あけ・印刷済みパネルを作ってもらう、ということも理論上は可能です。

部品実装

機械部品は表面、電子部品は裏面に実装しています。深さに余裕のあるケースを選択したおかげで、大型のフィルムコンデンサも余裕をもって実装できました。

表面は次のようになっています。

なお、物理的なマイクロフォニックノイズ対策は特にしていません。そもそもNutubeのあとの段で差動増幅していることで同相ノイズはある程度相殺できるのと、マイクロフォニックノイズによって真空管らしい音になる、説を多少信じているためです。

パネルの作成

ツマミが多いと、どのツマミがどのパラメータを操作するものなのか分かりにくくなります。ということで各ツマミやスイッチの用途を印刷したパネルを作成しました。これはコンビニの写真プリントサービスを使って厚紙（光沢紙）に印刷したものをカットして貼り付けています。

本来ならパネルを設計したあとにそれに基づいて穴あけをすべきなのですが、今回はそこら辺を雑にして先に穴あけをしてしまったので、試行錯誤で穴の位置やデザインを決める羽目になりました。

試奏と雑感

現時点での使用感はこんな感じです。バンドでがっつり使わないと分からないところもあるのですが、おおむね実用的なものになっているのでは？　という感想です。

エレキギターで使用した場合、JC-120（のアンプシミュレータ）でも十分に楽しい歪みサウンドになりました。

ベースで歪ませた場合は全体的に重めの歪みになる雰囲気で、軽く歪ませたいという場合はバランスが難しいかもしれません。

ギターでは基本ローカット設定で使う感じかなと。ベースの場合は原音ミックスを使えるのでローカットでもハイカットでも状況に応じて使えそうです。

ゲイン7～9時でほぼ歪まない真空管入りブースターとしても問題なく使えます。

マイクロフォニックノイズ（真空管自体の振動によって発生するノイズ）はスイッチを強く踏んだりすると聞こえるかな……？というレベルです。ポップノイズも問題にならないレベルかと思います。

電源ノイズに関してはかなり強く、ノイズ多めの電源アダプタでも出力にはあまりノイズ感はありません。ただ、アンプ側のゲインを上げると気になるのかもしれません。

[guitarbomb]

Vox Valvenergy Series 2 Pedals: Featuring Nutube Technology

Vox amps are legendary for their rich, tube-driven sound. Now, the Valvenergy Series 2 Pedals bring that classic vibe to your pedalboard.  Vox Valvenergy Series 2 These new additions – the Power Burst, Smooth Impact, Fuel Injector, and Tone Sculptor – are loaded with the revolutionary Nutube technology, ensuring each pedal mimics the response of a traditional tube amp. Previous models from 2020…

[ivan-fyodorovich-k]

look at the silly teacup I just won on eBay

it's a Noritake cup with Vox Amplifcation styling to commemorate their collaboration on "NuTube" technology

for some inexplicable reason I was the only bidder

[saltrock006]

単体で見ても大きいが、

まわりと比較すると更にデカさがw

どうしてこんなに大きくしたのだろう？

ツマミは操作しやすいので良いけどね。

ギターのVOL位置とピッキングの強さの組み合わせ、

これで出音をコントロール出来る。

出来るが、ピッキングの下手さが露呈する事多々。

中々に手強いオーバードライブだ。

Cindersに合わせてTone cutを調整。

その他に変化なし。

単体使用時のコンプレッション感は薄い。

これも設定次第なのだろうが、

NuTubeが仕事してないじゃん的な…

今の使い方だと美味しい部分を使えてない？

クリーン・チャンネル用に購入した。

Preampモードが一番自然なようだ。

前情報通りブライト・スイッチをいれると、

フェンダーのアンプみたいな音に変化。

当初はGainをゼロで完全にクリーンにして、

Persianで軽い歪みを加えていた。

それがどうもしっくり来ない。

試行錯誤の末にMystic edgeでクランチさせ、

Persianオンでアッテネートさせてクリーンにする。

今のところ、これがいい感触。

駆動電圧は18VでModernモードを選択。

本来の使い方ではないが、

上手くいけばすべて良し！

[cmangame]

NGƯỜI CHƠI MỚI CẤP TỐI ĐA – Khi game thủ thất nghiệp trở thành "trùm cuối" của thế giới thực

Tưởng chừng sự nghiệp Nutuber game của Jinhyuk đã chạm đáy khi tựa game Tower of Trials bị lãng quên... nhưng đời lại "lật kèo" một cách không tưởng! 💥

🗼Một ngày định mệnh, tháp thử thách Tower of Trials xuất hiện th��t giữa đời sống, kéo cả thế giới vào vòng xoáy sinh tồn chết chóc. Mỗi tầng tháp không còn là những level ảo, mà là những trận chiến khốc liệt sống còn giữa người với quái vật – giữa người với người!

🔥 Là người duy nhất từng “phá đảo” trò chơi này, Jinhyuk bỗng nhiên trở thành người chơi cấp tối đa giữa hàng triệu người chơi mới. Với vốn kiến thức sâu rộng về game, kỹ năng thượng thừa và thậm chí cả những “chiêu trò” mà chỉ người từng chinh phục mới hiểu, anh nhanh chóng xoay chuyển tình thế, dẫn đầu cuộc chơi – không phải bằng sức mạnh, mà bằng đầu óc và chiến thuật.

❗ Nhưng càng leo cao, Jinhyuk càng nhận ra những bí mật đen tối đằng sau tháp và những thế lực ngầm đang thao túng tất cả. Liệu anh chỉ là một con tốt bị lợi dụng, hay chính là người viết lại luật chơi của thế giới này?

📚 Đón đọc trọn bộ truyện Người Chơi Mới Cấp Tối Đa trên CManGa – nơi game không còn là trò chơi, mà là trận chiến sinh tồn thật sự!

📌 Ngoài ra, đừng bỏ lỡ các bộ truyện đang gây bão tại CManGa như Chủ Mẫu Xuyên Không Tới Làm Phu Nhân Hào Môn và Thiên Kim Toàn Năng Bá Khí Ngút Trời – cập nhật mỗi ngày, đọc miễn phí!

[meksynthesis]

新真空管Nutube搭載の人気ペダル！VOX VALVENERGY「 COPPERHEAD DRIVE」を弾かせていただきました！

the vox copperhead is an interesting pedal i encountered on my pedal hut; might get one for a friend in the future. it seems the claims of being a marshall in a box are somewhat true.

[newtras]

Korg is joining the turntable craze, offering portable options for archiving, DJing and more.

Korg is a name that usually reminds synthesizerskeyboards and production toolsbut ahead NAMM 2025the company announced new players. However, these are not just ordinary turntables sitting on a shelf and connected to speakers. Under the Handytraxx brand, Korg will soon offer portable players for listening, archiving and DJing, with some featuring branded turntables. Vacuum tubes Nutube. The…

[satrthere]

Korg is joining the turntable craze, offering portable options for archiving, DJing and more.

Korg is a name that usually reminds synthesizerskeyboards and production toolsbut ahead NAMM 2025the company announced new players. However, these are not just ordinary turntables sitting on a shelf and connected to speakers. Under the Handytraxx brand, Korg will soon offer portable players for listening, archiving and DJing, with some featuring branded turntables. Vacuum tubes Nutube. The…

[sakhshimandal]

The Best Vox Amps for Home Practice and Studio Recording

When it comes to choosing an amplifier for home practice or studio recording, musicians often look for a balance between sound quality, versatility, and size. Vox, one of the most iconic names in the world of guitar amplifiers, offers a range of amps that cater to both beginners and seasoned players looking for a great tone in a compact package. Known for their signature chimey, bright sound and rich tonal palette, Vox amps have earned their place as favorites for home and studio environments alike.

In this article, we will explore some of the best Vox amps for home practice and studio recording, focusing on their key features, sound quality, and versatility.

1. Vox AC15C1

The Vox AC15C1 is a classic choice for those who want legendary Vox tone in a smaller, more manageable package. With 15 watts of tube-driven power, the AC15C1 strikes the perfect balance between volume and portability, making it an excellent choice for both home practice and recording sessions. Its smaller size doesn’t compromise on tone – it still delivers the same sparkling cleans and gritty overdrive that the larger AC30 is known for.

The amp features a 12" Celestion Greenback speaker, which is renowned for its warm midrange and controlled highs, providing excellent sound reproduction. The AC15C1 comes with two channels: Normal and Top Boost. The Top Boost channel allows players to shape their tone with treble and bass controls, while the Normal channel offers a more straightforward sound for those who prefer a classic, uncolored tone.

For studio recording, the AC15C1 shines because of its ability to produce rich harmonic overtones at lower volumes. The built-in spring reverb and tremolo effects give you additional tonal options, making it a versatile choice for a wide range of musical styles.

2. Vox AC10C1

For players who need something even more compact and quieter than the AC15C1, the Vox AC10C1 is an excellent alternative. This 10-watt tube amp offers the signature Vox sound in a smaller, lighter package, making it perfect for bedroom practice and home studios where high volume levels might be an issue.

Despite its smaller size, the AC10C1 delivers a big sound with a 10" Celestion speaker, providing warm lows and bright highs that cut through the mix. The amp features simple controls – gain, bass, treble, reverb, and master volume – which make it easy to dial in a variety of tones, from clean and chimey to rich overdrive.

The AC10C1 is particularly well-suited for recording, as it delivers warm, tube-driven tones without needing to be cranked to high volumes. This makes it ideal for capturing high-quality sound in a home studio environment, where volume restrictions might be a concern.

3. Vox MV50 Series

The Vox MV50 series amps are a modern innovation in amplifier design, offering tube-like sound in a highly portable, lightweight package. Weighing in at just over a pound, the MV50 amps are perfect for guitarists who need a powerful amp head for practice and recording without the bulk of traditional tube amps.

The MV50 series features three main models: MV50 Clean, MV50 Rock, and MV50 AC. Each model is designed to emulate a specific tonal character, from clean, Fender-like tones to the classic Vox sound found in the MV50 AC. These amps use Vox’s Nutube technology, which emulates the sound and feel of traditional vacuum tubes while being more energy-efficient and compact.

For studio recording, the MV50 series is especially appealing because of its built-in EQ switches and line-out capabilities, allowing you to plug directly into a recording interface without needing a speaker cabinet. This direct output feature makes it easy to achieve high-quality recordings at home without the need for external microphones or complex setups.

4. Vox VT40X

The Vox VT40X is part of Vox’s Valvetronix series, which combines analog circuitry with digital modeling technology to offer a wide range of amp models and effects. This 40-watt amp is perfect for home practice and studio recording, offering a ton of versatility in a relatively compact design.

The VT40X features a 10" speaker and a selection of 11 amp models, including clean, crunch, and high-gain tones. It also offers a variety of built-in effects, including delay, reverb, chorus, and more, making it easy to experiment with different sounds without the need for external pedals. The amp’s USB connectivity allows for direct recording to your computer, making it a convenient choice for home studios.

One of the key advantages of the VT40X is its Tone Room editor software, which lets you customize and save your own amp models and effects. This level of flexibility makes it a powerful tool for players looking to record different styles of music in their home studio.

5. Vox Pathfinder 10

For beginners or players on a budget, the Vox Pathfinder 10 is an affordable option that still delivers that classic Vox sound. This 10-watt solid-state amp is compact and easy to use, making it ideal for home practice. While it doesn’t have the tube-driven warmth of some of the other models mentioned, it still provides a surprising amount of tonal variety for its size and price.

With simple controls and a headphone output for silent practice, the Pathfinder 10 is a great choice for players who want a small amp for practice without sacrificing too much on tone. Its portability and low cost make it an accessible option for those just starting out or those who need a quick and easy practice amp.

Conclusion

Vox offers a range of amps that cater to different needs, from compact practice amps to versatile models perfect for home studio recording. Whether you’re looking for classic tube warmth in the AC15C1, modern innovation in the MV50 series, or affordable options like the Pathfinder 10, Vox amps deliver high-quality sound and flexibility. Choosing the right Vox amp depends on your specific needs, but rest assured, any of these models will enhance your practice and recording sessions with that unmistakable Vox tone.

[a4w]

(「Vox Valvenergy 2nd Series」！Nutube搭載エフェクター第2弾！ - きになるおもちゃ -ギター・エフェクター・アンプ・DTM関連の情報サイト-から)

[m-ultiverso]

Thanks! Definitely looks like that. Interesting too. Solid state but with a Nutube. First I'm actually hearing of it. They didn't do much marketing on it apparently.

Yes, I found out now by doing some research based on the image, I didn't know this model either. lol

[mesotokyo]

最近またKORG Nutubeを触っているのですがピンが2mmピッチのうえにかなり柔らかくて扱いにくいので秋月電子で2mmピッチのピンヘッダを買ってきてはんだ付けしました。さすがに試作段階で直接基板にはんだ付けはしたくないですよね～。

[listamangas]

Novato solo a Nivel máximo

En curso 8.5/10

Autor: Yi-Deung-Byeol novela Sinopsis: Jinhyuk, un Nutuber de juegos, fue la única persona que vio el final del juego [Torre de pruebas]. Sin embargo, cuando la popularidad del juego disminuyó, le resultó difícil seguir ganándose la vida como Nutuber de juegos. Como ya había visto el final del juego, estaba a punto de dejar de jugar. Pero ese día, [Torre de pruebas] se hizo realidad, y Jinhyuk, que conocía cada cosa del juego, ¡se apoderó de todo más rápido que nadie! “Te mostraré como es un verdadero profesional”.

Lectura actual: 165

[sunalimerchant]

The Evolution of Vox Amps: From Vintage Classics to Modern Innovations

Vox amplifiers have a storied history that spans over six decades, leaving an indelible mark on the music world. Renowned for their distinctive sound and innovative designs, Vox amps have been a staple for iconic musicians and continue to be a favorite among guitarists today. This blog delves into the evolution of Vox amplifiers, tracing their journey from vintage classics to modern innovations, and exploring how they have remained relevant in the ever-changing landscape of music technology.

Early Beginnings and the Birth of a Legend

The story of Vox amps begins in the late 1950s with the founding of the Jennings Musical Industries (JMI) in Dartford, England. The company's first major breakthrough came with the introduction of the Vox AC15 in 1958. The AC15 quickly gained popularity for its unique sound, characterized by a bright, jangly tone that was perfect for the emerging rock 'n' roll scene. Its success paved the way for the development of what would become Vox's most iconic amplifier, the AC30.

Introduced in 1959, the Vox AC30 was designed to meet the growing demand for a louder amplifier that could fill larger venues. It featured two 12-inch speakers and 30 watts of power, which was a significant increase from the AC15's single speaker and 15 watts. The AC30's distinctive chime-like tone, achieved through its use of EL84 power tubes and the famous Top Boost circuit, quickly caught the attention of influential British bands like The Beatles and The Shadows, cementing Vox's reputation in the music industry.

The Golden Age of Vox

The 1960s were a golden age for Vox amplifiers. The AC30 became synonymous with the British Invasion, gracing the stages of legendary bands like The Rolling Stones, The Kinks, and The Yardbirds. Its ability to produce both clean and overdriven tones made it incredibly versatile, and its robust construction ensured reliability on the road.

During this period, Vox continued to innovate with new models and features. The Vox AC100, also known as the Vox Super DeLuxe, was introduced to cater to the increasing demand for more powerful amps. Vox also experimented with transistor technology, releasing the Vox Super Beatle and the Vox T60, which found favor with bassists and keyboardists.

Challenges and Resurgence

Despite its early success, Vox faced significant challenges in the late 1960s and 1970s. The rise of American amp manufacturers like Fender and Marshall, combined with financial difficulties at JMI, led to a decline in Vox's market share. However, the company's acquisition by the Rose-Morris Group in the early 1970s provided a much-needed lifeline.

The 1980s and 1990s saw a resurgence of interest in vintage gear, and Vox amps experienced a renaissance. Musicians began to rediscover the unique sound of vintage AC30s, and the demand for reissues grew. Vox responded by reissuing classic models with modern updates, ensuring that the iconic sound of the AC30 remained accessible to new generations of musicians.

Modern Innovations and the Future of Vox

In recent years, Vox has continued to innovate while staying true to its heritage. The company has expanded its product line to include a variety of amplifiers that cater to different needs and preferences. The Vox Valvetronix series, for instance, combines analog tube technology with digital modeling to offer a wide range of tones and effects. The Vox Mini Superbeetle, a compact amp with vintage styling, pays homage to the classic design while incorporating modern features like Bluetooth connectivity.

One of the most significant innovations in modern Vox amps is the introduction of the Nutube technology. Developed in collaboration with Korg, Nutube is a new type of vacuum tube that offers the same warm, rich tones as traditional tubes but with greater efficiency and reliability. This technology has been incorporated into several Vox models, including the MV50 series, which delivers powerful tube-like sound in an ultra-compact form factor.

Conclusion

The evolution of Vox amplifiers is a testament to the company's commitment to quality, innovation, and timeless sound. From the vintage classics that defined the sound of the 1960s to the modern innovations that continue to push the boundaries of amplifier technology, Vox has remained at the forefront of the music industry. Whether you're a seasoned professional or an aspiring guitarist, Vox amps offer a rich legacy of tone and performance that continues to inspire musicians around the world.

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