MS Vienna
Well-known member
The times when the VM1 was hyped are long gone.
Almost 10years ago I witnessed a shootout as a friend planned to buy one. It did sound fine and he got one.
A bit later I got a deal on a VM1 that has been sitting in a showcase but unused and with full warranty. And for the price I jumped on it. It even sounded a bit more balanced than the friend´s specimen.
However it never became a favourite of mine. I felt something was wrong with the sound. It just didn´t sound "right", "true".
So after the warranty extinguished I opened it and looked what could be done.
I started with the coupling cap. It´s a big Wima MKS 1µF 250V.
I tried out various capacitors. When I got to the russian PIOs it got better (for my taste).
In the end of capacitor testing I settled on a well proven, high quality model for it offered least sound degradation and best transient transmission. Sonically almost "invisible".
I noticed that this forum is pretty heavily focused on the U47, so many of you might recognize this classic cap:
In order to mount it I made a brass brigde that I screwed onto the VM1´s frame. Luckily there´s plenty of space inside so it´s a perfect fit.
The nice thing about the Bosch is that you can get three different capacitance values depending on how it´s terminated.
Almost 10years ago I witnessed a shootout as a friend planned to buy one. It did sound fine and he got one.
A bit later I got a deal on a VM1 that has been sitting in a showcase but unused and with full warranty. And for the price I jumped on it. It even sounded a bit more balanced than the friend´s specimen.
However it never became a favourite of mine. I felt something was wrong with the sound. It just didn´t sound "right", "true".
So after the warranty extinguished I opened it and looked what could be done.
I started with the coupling cap. It´s a big Wima MKS 1µF 250V.
I tried out various capacitors. When I got to the russian PIOs it got better (for my taste).
In the end of capacitor testing I settled on a well proven, high quality model for it offered least sound degradation and best transient transmission. Sonically almost "invisible".
I noticed that this forum is pretty heavily focused on the U47, so many of you might recognize this classic cap:
In order to mount it I made a brass brigde that I screwed onto the VM1´s frame. Luckily there´s plenty of space inside so it´s a perfect fit.
The nice thing about the Bosch is that you can get three different capacitance values depending on how it´s terminated.