ChuckD
Well-known member
OK I just wanted to start a thread on the GT mic parts etc I picked up at the LA sale this weekend.
Firstly, Aspen was selling of all the boards and parts so I think the design is fair game now.
The MD1 is a Cathode Follower design into a Cinemag CM-9336 transformer. The PCB around the tube uses the 7,8,9 side of the tube as the first (AKG C12-C24) type gain stage then like the Chinese models it uses the 1,2,3 side of the tube as a Cathode follower. I will try to draw a schematic tonight.
Here is the Transformer info straight from Cinemag:
I spoke with them on the phone as well and they do not recomend the CM 9336 as it is a single bobbin and relatively cheap in design for a high end build.
I also mentioned that Aspen was recommending that the CM9911 could be used as the CM2480 as a great replacement in the Chinese mics. This should be taken with a grain of salt as the 9911 is a 5:1 ratio while the 2480 is a 10:1. So with the 9911 a PAD would be required most likely. This is very design dependent but the APEX460 etc. mod should use the 10:1. I think I will try one just to see.
I know many other picked up this stuff too so post some ideas!
-ChuckD
Firstly, Aspen was selling of all the boards and parts so I think the design is fair game now.
The MD1 is a Cathode Follower design into a Cinemag CM-9336 transformer. The PCB around the tube uses the 7,8,9 side of the tube as the first (AKG C12-C24) type gain stage then like the Chinese models it uses the 1,2,3 side of the tube as a Cathode follower. I will try to draw a schematic tonight.
Here is the Transformer info straight from Cinemag:
We have not made data sheets for either of these transformers. Sorry, but we manufacture so many that it is impractical to compose one for each.
The CM-9911 is a 5:1 microphone output transformer. Aspen's price of $20 was a give-away compared to what Alesis paid for it. Be sure that the turns ratio is what your circuit is suited for.
The CM-9336 was a 4:1 cathode follower microphone output transformer. It was inexpensive, but did a decent job. It is not in current production.
Aspen owes us lunch for all of the inquiries we are getting about these transformers. lol
Best regards,
David Geren
I spoke with them on the phone as well and they do not recomend the CM 9336 as it is a single bobbin and relatively cheap in design for a high end build.
I also mentioned that Aspen was recommending that the CM9911 could be used as the CM2480 as a great replacement in the Chinese mics. This should be taken with a grain of salt as the 9911 is a 5:1 ratio while the 2480 is a 10:1. So with the 9911 a PAD would be required most likely. This is very design dependent but the APEX460 etc. mod should use the 10:1. I think I will try one just to see.
I know many other picked up this stuff too so post some ideas!
-ChuckD