MA1 GERMANIUM mic pre support thread

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ppa

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desol said:
ppa said:
here the drums:

http://home.teletu.it/APPSI/DRUM%20OVERHEAD%20%20MA1_1.wav

Short clip..?!

yes, but a customer said me that his MA1's sound better that these files let think, so I am thinking to remove them.
However, I am waiting that the other customers have their MA1's running to get other files, better than these ones.
BTW comments (good and bad) are welcome on these files.
 

sr1200

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As soon as I can get transformers from Jeff at Classic API, im going to be doing a shootout for guitars/drums/vocals/bass/horns with the pre's i have in my studio (including the MA1's...lots of others as well)  Probably be done by the end of feb if shipping isnt delayed.
 

ppa

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a customer of mine has sent me some links of video registered with 3 MA1's

the voice is registered with an MA1 ,

http://www.youtube.com/watch?v=tyoevFLCUvg


http://www.youtube.com/watch?v=nnjUvN7wLBw


the other preamps are APP1040's with APP2050E inside and API512's with APP2050E

EDIT: APP1040 is a preamp I have designed. It is basically a 312 pre with a DC servo integrator. 



 

sr1200

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Just a couple of notes for anyone looking to build these. 
1) EASY EASY EASY build. (theres 1 errata on the board which is easily fixed in 2 seconds)
2) No hens teeth parts to find.  Everything is pretty straight forward and easily procured.

Im going to be doing a bit of a shootout with the pres in my studio, both commercial units as well as DIY to (hopefully) show the tonal variations and responses of the various pres.  Ill post here and have a new thread once its all together. 

Initial tests of the unit are very interesting in a good way! :)
 

okgb

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In case it wasn't obvious [ to me ] forgot the jumpers at the output transformer
the 2 solid white lines between via's  , Preamp works and sounds pretty nice , Thanks Pier
anyone try different transformers ? [ other than api type ]
 

ppa

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okgb said:
In case it wasn't obvious [ to me ] forgot the jumpers at the output transformer
the 2 solid white lines between via's  , Preamp works and sounds pretty nice , Thanks Pier
anyone try different transformers ? [ other than api type ]

yes, I agree with you, I am going to post a photo to indicate tgis two bridges to solder between these holes.

thanks for comments!
 

ppa

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sr1200 said:
Just a couple of notes for anyone looking to build these. 
1) EASY EASY EASY build. (theres 1 errata on the board which is easily fixed in 2 seconds)
2) No hens teeth parts to find.  Everything is pretty straight forward and easily procured.

Im going to be doing a bit of a shootout with the pres in my studio, both commercial units as well as DIY to (hopefully) show the tonal variations and responses of the various pres.  Ill post here and have a new thread once its all together. 

Initial tests of the unit are very interesting in a good way! :)

thanks for comments!
yes, the circuit is simple. Moreover there are no DOA's inside.
Comparative tests are welcome, they are needed here , many thanks
 
 

sr1200

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Just used the MA-1 on a session this past week.  Used it on part of the drum kit and am using it for a bass track tonight.  My ONLY complaint (or should I say request) would be for there to be a output trim on this bad boy.  I'd LOVE to saturate the hell out of this puppy and see what she can spit out.  Im thinkin, perhaps I can get rid of the DI and put a T-Pad in there.
 

Indecline

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sr1200 said:
Just used the MA-1 on a session this past week.  Used it on part of the drum kit and am using it for a bass track tonight.  My ONLY complaint (or should I say request) would be for there to be a output trim on this bad boy.  I'd LOVE to saturate the hell out of this puppy and see what she can spit out.  Im thinkin, perhaps I can get rid of the DI and put a T-Pad in there.
I'm planning on grabbing a couple in the next month or so and wanted to do this as well. Do you think it will physically fit where the di is?
 

sr1200

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He left quite a bit of room there since the DI jack is NOT soldered directly TO the board. (so good thinking on PPA's part). Only issue might be securing it to the front panel since i think a 1/4" jack requires a larger bore than the T-Pad. Nothing a locking washer and nut cant handle im sure, but we'll see.
 

ppa

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thanks for comments,

I am seeing if it is possible to insert a TPAD attenuator or another output attenuator on the DI hole,
I am thinking on a stepped attenuator for out.

How much dB of attenuation are required? 
 

ppa

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is should possible use the T-pad used for classicapi pres, these are the link

http://classicapi.com/catalog/product_info.php?products_id=254

http://classicapi.com/catalog/product_info.php?cPath=48&products_id=255

I have not yet tested it on MA1 but theoretically is possible using it also here.

The T-pad could be inserted into the MA1's DI hole in place of the jack connector.
 

ppa

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Winetree said:
I have a pair of MA1s.
How do you wire the T-Pads?

using the T-Pad PCB Adapter by Classicapi in this link:

http://classicapi.com/catalog/product_info.php?cPath=48&products_id=255

to wire this PCB inside the preamp:


1) the + in  hole of the T-Pad PCB Adapter goes to the brown wire of the out transformer

2) the -  in hole of the T-Pad PCB Adapter goes to the yellow wire of the out transformer



3) the - out  hole of the T-Pad PCB Adapter goes to the yelow hole of the MA1 board

4) the + out hole of the T-Pad PCB Adapter goes to the brown hole of the MA1 board


all wires should be twisted pair





 

manulaudic

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Hi !

Anyone got any luck with using a t-pad with this circuit? Were you able to push it into some sort of overdrive or nice harmonic thingy?

Anyone thought of having a feedback control ?

M
 

Mrosso

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Blew R31 and R29. Anyone have any idea why these two resistors blew? The diodes seem to be in the right orientation. I followed the BOM, both 10 Ohm. Would it be possible that I inserted it into the 51X rack incorrectly? It blew the +16v fuse on my floor power supply. I'm praying it didn't f'up my other six modules or the rack. I'm thinking it may have misaligned and got into the 24V pins on the card edge connector. Thoughts?
 

ppa

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first all , you should check if Q4 and Q2 are inverted (Q2 in the place of Q4 and viceversa), please.
 
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