【English Subs】Marshall JMP-1 repair【Repair Report】
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- Опубликовано: 12 сен 2024
- MIDI制御のプリアンプ Marshall JMP-1。
1Uサイズに歴代Marshallサウンドが詰まった名機で
生産終了からだいぶ経ちましたが、今でも愛用者の多い1台です。
今回は、使用中音量が不安定という個体をお預かり
当店でよく行うメンテナンスのメニューを行いました。
リペアについてのお問合せはホームページのお問合せからお願いいたします。
お問合せはこちらから
nsdworks.net/co...
Preamplifier with MIDI control Marshall JMP-1.
The Marshall JMP-1 is one of the most popular preamps in the world.
It's been a long time since its production ended, but it's still a favorite of many people.
In this video, we took it in for repair because the volume was unstable while using it.
We performed the maintenance menu that we often do in our shop.
If you have any questions about repairs, please contact us from the website.
nsdworks.net/in...
Translated with www.DeepL.com/Translator (free version)
Can you do English videos? You are a great tech
thank you.
Although I can write English, I'm not good at speaking it. Like many Japanese people.
参考になりました
電源インレット近くのリバースロックが取れなくて四苦八苦
ラジペンの柄を延長させて基板の下に滑り込ませて抜きました
レビューおめでとう！僕もjmp1を持っていて、2台のアンプの "マスター "から "パワーアンプ入力 "に使っているんだ。2つの出力チャンネルに音量の差があることにいつも気づいていました（大きくはありませんが、あります！）。これは正常なことなのでしょうか？それとも両方のチャンネルが同じレベルであるべきなのでしょうか？ 具体的には、フェンダーのEighty-Fiveを使っているのですが、パワーアンプのインはすべてをキャンセルしてしまうので、jmp-1のボリュームでコントロールするしかありません。もう片方のチャンネルでは、マーシャルの8080の「リターン」を使っていて、jmp-1に加えてマスターボリュームとリバーブを自由に使うことができます。
すでに2台のアンプを逆にしてみたが、違いは消えない．
(私はイタリア人で、オンライン翻訳機を使っています。）
ありがとうございました。
では
ジュゼッペ
Explanation - The "Level" control on the front panel of the JMP-1 controls how much output is sent to the Output Jacks. This control is what is known as a "Dual Ganged" control pot. IE: When you adjust the "Level" control you are simultaneously adjusting
(2) control pots.
The problem is that both pots on the "Level" control are not matched. IE: as you increase the Level there will be spots where one side is louder than the other. All replacement pots have the same problem.
Solution - 1.) Adjust the rig to the desired stage volume. 2.) Use the power amp's Level / Volume controls to balance the volume.
@@きら-c9p thank's
さすがです！
Great video! If I touch the output button on my jmp-1 the sounds cuts out and in. Do you have any idea what that could be? Do I need to replace it?
Thank you.
I may suspect the sound cutting out is the solder and the op amp M5201.
Other than that, I would have to check your JMP-1 to determine the cause.
Hi Sir. Glad if you can help me.
My unit does not work on the Clean Channels (no sound at all). The OD channels work perfect. Could you please give some orientation where the problem is, and if it's fixable? (I live up north in Argentina and rare parts are not available here...nor specialized techs. I wanna help mine as much as possible).
Thank you very much for your time.
I will look at the schematic and other possible locations and present them to you later.
Please give me a few days.
Thanks.
Thank you very, very much!!@@nsdworks
Hi there, I'll be grateful if you help. Mine has wave-like vibrating/oscillating noise (like 2-3 waves per second) on OD channels. I actually applied every thing on this video (but not the ICs). The hum is still there. Do you have any idea? Or can I send you mail to explain more details?
Just to confirm, do you have any cell phones or other devices nearby?
If you hear a periodic pulse noise, it is often due to a cell phone in your pocket.
You may also be aware of the effects of the crisis around the rack.
It may be difficult to provide further assistance by e-mail, as we cannot diagnose without seeing the actual equipment.
My English skills are also limited in responding.
@@nsdworks Actually I don't remember my phone was nearby or not. But anyway I'll give that a shot. By the way I'm not sure that the tubes are in good or bad condition. Do they have a direct effect on noise?
@@erkamgulluoglumusic
It's unlikely that the vacuum tube is faulty, but if you can replace it, you should try.
You did replace the electrolytic capacitors in the power supply, right?
Three 10µF/350V. three 2200µF/25V.
@@nsdworks I see. Then I'm not touching the tubes.
Yes I replaced all those capacitors you mentioned. Also I have a transformer hum too, it's not loud but it gets louder when the top covering is installed.
@@erkamgulluoglumusic
Transformer noise is a physical vibration, right?
It's not the noise coming from the speakers, is it?
You can't control that anymore, so you shouldn't worry about it.