Masco MA35
Hey, Skip.
LOVING my MA17 that you refurbished!
What do you think about Masco MA35s for harp, in general? Unnecessarily complicated to mod for harp?
To be less specific, which Mascos (or any other "similar" models) do you consider the most prime candidates for refurb/modding, if one is looking for more power?
(Not like I need another amp, but why let that stop me?)
Unrelated question: is a line out on the MA17 a reasonable thing to add?
Thanks,
Mark Heffington
Hi Skip! I've got a Masco MA 25P that came my way for little $. For those who don't know the P means it has a removable phonograph. I got that too but wow is it old so I removed it! the amp has two 6L6 power tubes that I wouldn't touch for concern about the biasing but I did remove one of the preamp tubes to bring down the volume. Someone mentioned the amp could be adjusted by something called making this a self split amp by grounding the input on the out of phase tube. Is this a big proposition or something that could be done relatively easily and inexpensively? Thanks!
So, the line out is just a 1/4" jack wired in parallel with the speakers, with a resistor across the positive and negative terminals of the line out jack, and another resistor between the positive speaker output and the positive line out terminal? For an MA-17 wired for 8-ohm speaker output, would the values of there sistors be in the range of 270 ohms between the positive and negative line out terminals, and 2700 ohms between the positive speaker lead and the positive line out terminal, theoretically? I believe I have seen these values used, but I have also seen schematics using 1K and 10K resistors.
Thanks!
Hello Mark- I'm not a big fan of the 35s. I've seen at least two different versions, but they are all a bit too complex in my opinion. I HAVE done quite a few MA-25s for harp and they also need some serious modifying in order to be real "harp-friendly".
I think that there are a great many other amps by Stromberg, Bogen, Dukane, Knight, etc. that have real potential. Remember, it took me quite a while to come up with the circuit I use on the 17s. Of course a monstrous debt to all the great players who told me what they thought.....
Yes, a line-out is a great idea. Use it to "slave" in to bigger amp onstage or go straight to the PA system without miking. Be sure to use the "speaker-driven" circuit...... it's only one 1/4" jack and two resistors, but works great!
Be sure to use a big 'ol speaker cab with your 17 before you decide that need more power. They get pretty punchy when hooked up to 4-10s. (hint: an RI Bassman makes a great cab)