Acm-900

[P. Glaser]

OK, I know there were about 75-80 of us that ordered an ACM-900 in the GB. What are your plans for modding? (of course we'll have to try them out first). Anyone? Thanks.

 

[antichef]

I thought I saw two transformers in the cross section....

 

[P. Glaser]

Yeah. The pix are on Chance's website here:

http://the-musicians-workshop.com/

Did you order one? What are your plans? Thanks.

Paul

 

[antichef]

I ordered an ACM-900 - yes. I really have to wait to see it (and certainly to soak up the sage advice of the many, many folks here who will know better what to do than I will), but the transformers look like the ones I replaced to good effect in the last round of GB ribbons. Have to wait to see what specs the replacements should have. I'm liking the Edcors that I have, and they're inexpensive.

 

[P. Glaser]

That was my plan as well. I also ordered a 310 so I'll be watching that thread.

 

[WhiteStrat]

I ordered an ACM-900 - yes. I really have to wait to see it (and certainly to soak up the sage advice of the many, many folks here who will know better what to do than I will), but the transformers look like the ones I replaced to good effect in the last round of GB ribbons. Have to wait to see what specs the replacements should have. I'm liking the Edcors that I have, and they're inexpensive.

Yeah, after he soaks it up, I'll ask him to dribble the wisdom down to me--then I'll panic and probably do nothing.

...must be strong...

 

[thebwack]

i ordered this one, really curious about it. i've looked a few times through the posts for this...

will the tube be socketed in the final production of the ACM-900? i knew some of the mics had some changes since those pictures. just curious...

 

[Marik]

The 1st transformer ought to be a real big ratio--something like 1:200. Otherwise it doesn't make any sense--the noise will be way up and tube work with way too low source impedance.
If somebody has the stock transformer and willing to send my way, I will be more than happy to measure it.

Best, M

 

[antichef]

More on this one... The tube is a 6J1 (*not* a 6J1B, which has flying leads instead of pins). Recordinghacks has this page on them: http://recordinghacks.com/microphones/tag/6j1

The common old stock designations for this tube are EF95 (European?); 6AK5 (American commercial?); and 5654 (American military?)

The good news is that there are a bunch of them out there! - I picked up a handful this morning locally and tried them out. I've got an RCA in place now, and I hear a definite improvement over the stock tube. Less wooly - better highs, better lows.

As most of us probably know by now, the transformers are in little (mu-metal?) boxes -- I think I'm gonna wait to see what TnC come up with before I try anything crazy with them.

 

[antichef]

Don't mean to be a re-animator, but I pulled out my ACM-900 this weekend, and used it some, mostly with the ACMP-73 preamp w/o EQ. Nice!! I've started layering tracks of crappily performed vocals, and it's going well. I also gave it the torture-test - my toddler singing her repertoire of children's songs -- and again, it performed admirably.

When she was singing in the front, I thought I could stand in the back and sing/talk, but it was almost like the back was in a nearly-null spot -- not acting like a figure 8 - not sure what's going on there, because it doesn't make sense - I'll do some more research.

Mine is still stock, except for an RCA tube that I put in - details here ( https://homerecording.com/bbs/showthread.php?t=278255 ).

Anyone else using one of these?

 

[P. Glaser]

Don't mean to be a re-animator, but I pulled out my ACM-900 this weekend, and used it some, mostly with the ACMP-73 preamp w/o EQ. Nice!! I've started layering tracks of crappily performed vocals, and it's going well. I also gave it the torture-test - my toddler singing her repertoire of children's songs -- and again, it performed admirably.

When she was singing in the front, I thought I could stand in the back and sing/talk, but it was almost like the back was in a nearly-null spot -- not acting like a figure 8 - not sure what's going on there, because it doesn't make sense - I'll do some more research.

Mine is still stock, except for an RCA tube that I put in - details here ( https://homerecording.com/bbs/showthread.php?t=278255 ).

Anyone else using one of these?

I tried a vocal thru mine when I first got it and didn't like it at all. I did some hand claps thru it recently and they sounded good. I should try swapping out the tube. I think there are a few component swaps out there as well.

Paul

 

[dgatwood]

When she was singing in the front, I thought I could stand in the back and sing/talk, but it was almost like the back was in a nearly-null spot -- not acting like a figure 8 - not sure what's going on there, because it doesn't make sense - I'll do some more research.

It's consistent across all the lollipop ribbons. I think it has to do with reflections off the grille and/or pole piece somehow causing the polar pattern in the near field to be wretchedly uneven. It behaves like a cross between figure-8 and omni, with lots of odd phase cancellation off the back side. Very odd. Back off a couple of feet and it behaves exactly as you would expect.

 

[antichef]

I tried a vocal thru mine when I first got it and didn't like it at all. I did some hand claps thru it recently and they sounded good. I should try swapping out the tube. I think there are a few component swaps out there as well.

Paul

I've got lots of NOS tubes for it, btw - PM me if you want one.

 

[Tajmoben]

I've got lots of NOS tubes for it, btw - PM me if you want one.

I'd like to try some different tubes in mine sometime. At the moment it sounds really crisp way more than any other ribbon I've used. I haven't used it a whole lot though....if I put up a ribbon it's usually either the ACM-3 (I've been getting good results w/ these) or a Fathead (which I'm just not that crazy about).

 

[BobbyBalow]

My 900 was really dead sounding. It reminded me of a very lo fi recording with almost no 8k or above. But the vocalist was very close to the ribbon... I'm looking to pick up a new tube for it if it will clean it up a bit. Send me a pm with a price and I'll let you know.

 

[antichef]

echh. I left mine on for a few days, and now it seems to have a raspy hiss. Looking into it. I PM'ed you Bobby. The tubes are price-less - seriously, I grabbed a few extra for other ACM-900 owners, and they were so cheap that it's not worth selling them - happy to send one your way.