Hello everybody, I would like to add a line out to my HD-150, located right before the Main Volume. I have an early one with a BB-2 PC-Board, looks like an upgraded BB-1. the Volume pot is a single one with 10k. So now my idea. I would like to rebuild the line out Unit from the Music Man 100-B (Chassis 2100-B) from behind the line out Level poti. What is your oppinion?
Wed, 01/24/2018 - 05:25
#1
Dieters
Not a bad idea
Hello Dieters,
You can grab signal from the top of the master volume pot, run it to a stage with, say, 6dB of gain (can dial in to taste of course), a line out volume control and end with a buffer stage for a low output impedance. If you need the balanced output as found in the B-100 circuit you can of course copy that, but for a basic 1/4" line out it doesn't have to be that elaborate. The power supply in the amp will easily accommodate another dual op-amp chip and there is ample room to mount it somewhere inside. The only issue could be adding the output jack and line out volume control in the chassis - you may have to drill a hole unless you want to sacrifice one of the dual input jacks and hardwire the mid control to neutral on one of the channels.
Cheers,
Lars Verholt
Hello Lars, thank you very
Hello Lars, thank you very much for your reply. I am going to build it up like in the B-100. I will only take the balanced output. There is already a xlr out in the back panel of my amp. 35 years ago, I brought it to a music store for adding a DI-Out. They only put a transformer into it and took the signal from the speaker out. So I had always the situation, the DI signal was depending on the output volume. With the new solution I can put my sound into the mixer and have an independent stage volume level. I keep you updated ...
Ready to modify and install
Dear community,
I have finished rebuilding the pre out circuit from the 100B. Now I‘m not shure whether my ideas of connecting it are good.
I added some pictures to describe.
Pictures follow...
First of all I have to explain once again. I want to add the XLR pre out from the 100B to my HD 150. My HD 150 has the BB-2 Board. I want to install a Volume poti in the rear to adjust the level of the signal. So I will take a 47kL poti and take the signal from the top of the master pot. The rebuilt circuit starts behind the pre post pot from the 100B. Hope, everything is clear ;-)
Waiting for your comments...
The circuit
On the right the rebuilt circuit and on the top the layout plan from the 100B
BB-2 layout
The cross in the yellow field shows the point where to grab the signal
Mod: HD 150 with DI-Out from 100B finished
Dear community, it took some months to finish this project. I mounted and wired all the parts and now I am really happy about the result. The only bad thing is that it wasn´t possible to get an original knob :-).
So my HD150 has got a symmetrical DI-Out with adjustable level and it works really fine. Thanks for the support and keep on rockin´.
Cheers,
Dieter