Weak positive input from Nakamichi BX-300

Hello, I have a Nakamichi BX-300 tripple head machine as source to digitilize my massive collection of demo tapes.

It seems that I have the problem with the right channel. However I am not to good reading the meter but can both see and hear that the right channel is incorrect. What I don’t understand is the scale +1 and -1 (-1 seems good). Can anyone tell me what I see so I can trouble shoot my tape machine

so I can trouble shoot my tape machine

Or maybe not. That machine is a terrific but analog tape machine. How did you get the sound into the computer? That step kills a lot of people.

The bottom (right) channel is low level and heavily distorted. Note the tops do not match the bottoms of the blue waves, but in the Left channel, they do.

The blue wave range is in percent, 100% up and down. Louder than that, the digital system can no longer follow the music and creates very serious and obvious distortion. The meters (depending on how you have them set) run in “real” dB and work like your ears do, the blue waves are set like that because for many people it’s easy to edit. The blue waves will not show you the full range of sound volume, but the sound meters do.

Your serve.


Have you cleaned the heads and the transport mechanism (the capstan and the pinch roller)?
See this page in the Audacity Wiki: http://wiki.audacityteam.org/wiki/Recording_from_Cassette

Also it’s worth running the tape from end to end and back again before you start the recording to retension the tape (especially if it’s been standing stored for a long while).

I had my Nakamichi BX-2 professionally serviced before I undertook my tape digitizations as I had many unrepeatable tapes.


One test you can make: Reverse the left & right connections at the tape deck, and see if the problem follows. (That is if the problem now shows up on the left channel in Audacity you know the problem is in the deck).

I would wager from that waveform that the right head preamp is failing, possibly as simple as a bad capacitor, or possibly something worse.

I realized this morning that there is another possible cause of your asymmetric waveform from the deck – badly magnetized playback heads. Do you have a suitable head degausser?

Dear all, thanks for your input!

I have changed the cables but the issue remains (it is the right channel that is the issue). I also know that my Analogue to Digital converter (Furutech GT40) is okey as other line sources don’t have this problem. I have tried several tapes and they all look the same on the graph. I have also cleaning the machine per instruction but nothing matters. I have on top of this consulted the NAKA manual without any ideas.

Looking at the comments above. My trouble shooting goes as following

A) Demagnitize the heads. I don’t have the equipment for it. Need to find such and figure out how to do it.
B) Tight head preamp is failing, possibly as simple as a bad capacitor. With regards of B I assume this is someting inside the Nakamichi tapemachine you are refering to?

A friend talked about azimut settings (not sure what it is but beleive it has something to do with the alignment of the playback head) which could be the issue.

The Wiki article for which I posted a link for you discusses azimuth settings: http://wiki.audacityteam.org/wiki/Recording_from_Cassette#Azimuth

One thing you could try is to correct this in software.

You can use Audacity’s Normalize effect to normalize each stereo signal independently so your bottom track would be boosted more than the top one - see this page in the Manual: http://manual.audacityteam.org/o/man/normalize.html

But, having said that, it is still much better to fix the signal at source in the hardware :nerd:


Thanks for all input. I did the azimuth tuning yesterday after consulting my the technical manual. Reading the very helpful comments above it seems to be someting related to the signal processing in the machine, but not related to the head itself.
Someone mentioned the capacitors which was a good lead. I found someone who seems to have the exact same problem as me, see the link below


Apparently the “Orange Cap Disease” is a well know fault on the Nakamichi machines. I will send the machine to a professional electronic repair shop who can trace where there are signls flaws comparing the correct channels.

By the way (just for securing that another reader get the exact information). It is actually the left channel have the aymmetrically limited output. I have switched the output cables when I ripped.

I give you all a heads-up when the machine is back from the repair shop. Once again, thanks everyone for your valuable input.

Hello everyone. It was a faulty cap. All “orange” caps has been replace and the machine is as new. I will continue the ripping, thanks everyone