MA1 GERMANIUM mic pre support thread

[ppa]

This is the support thread for MA1 GERMANIUM mic/di pre.
MA1 is a new pre I have designed some months ago.
This thread is dedicated for the assembly work.
BTW it is also a very good space for other infos and your impressions on this preamp.

thanks for looking.

 

[Fablab]

Email sent!

 

[[silent:arts]]

Pier, received the kit 8)

any schematic or PCB overlay with resistor values would be nice  ;D

 

[ppa]

Pier, received the kit 8)

any schematic or PCB overlay with resistor values would be nice  ;D

my ecological mania to save trees! 

I had not supposed that german post would be been so fast, I am sendig all to you by email.  ;D

BTW often I prefer to not send many sheets by registered mail because is not so cheap to do. 
I avoid it to save customers' money. (and trees) 8)


kind regards
Pier Paolo

 

[Pliplo]

Hi guys, since i just bough a kit and im a noob... i figure it cant hurt if i check this... i was making a classicapi.com cart to get the missing things from the kit... if anyone can confirm id appreciate it

1 x EA 2503 Output Transformer http://classicapi.com/catalog/product_info.php?cPath=21_37&products_id=79

1 x EA 2622 Input Transformer http://classicapi.com/catalog/product_info.php?cPath=21_38&products_id=80

4 x C&K 2PDT Pushbutton Switch http://classicapi.com/catalog/product_info.php?cPath=51_52&products_id=88

The two things im not sure about are the bourns pot (which one?) and the size of the aluminum knob... Is that it or am i missing something else? Neutrik jack maybe?

Cheers

 

[ppa]

Hi guys, since i just bough a kit and im a noob... i figure it cant hurt if i check this... i was making a classicapi.com cart to get the missing things from the kit... if anyone can confirm id appreciate it

1 x EA 2503 Output Transformer http://classicapi.com/catalog/product_info.php?cPath=21_37&products_id=79

1 x EA 2622 Input Transformer http://classicapi.com/catalog/product_info.php?cPath=21_38&products_id=80

4 x C&K 2PDT Pushbutton Switch http://classicapi.com/catalog/product_info.php?cPath=51_52&products_id=88

The two things im not sure about are the bourns pot (which one?) and the size of the aluminum knob... Is that it or am i missing something else? Neutrik jack maybe?

Cheers

all these things should be bought to classicapi.com.
I council classicapi because my prototypes are assembled with these ones and worked very fine,
BTW Jeff does a very good service.

pot's link is http://classicapi.com/catalog/product_info.php?cPath=50_131&products_id=84

knob's link is http://classicapi.com/catalog/product_info.php?cPath=23_40&products_id=60

jack's (neutrik) link is http://classicapi.com/catalog/product_info.php?cPath=84_106&products_id=190

these components (transformers, switches, pot, knob and jack) are used inside calssicapi pres and they are of high level quality.

The  EA 2622 is a high level component, I prefer it to other exspensive trasformers for performances but it has a much lower price, it is a big deal in my opinion , I council it for this reason. Same thing for the EA 2503and also for the other components too.
thanks for your post
kind regards
Pier Paolo

 

[Pliplo]

Thanks good sir! Anyone who finish theirs have any opamp recommendations? I currently have some gar2550s and gar1731s. Would it be "too much" if i put one of your germanium opamps inside?

 

[okgb]

It already has the Germanium transistor in it , that is why you bought it , no ? [ didn't look ? ]
anyway as volker points out [ and confirmed by the picture above ] there is no
swap-able  2520 style DOA footprint

 

[[silent:arts]]

You noticed this is an op-amp free design?

 

[3nity]

OOOOOOOOOOOOOOOOOOOPPSSSSSSSSSSSSSSSSSSSSSSSSSSSS

 

[okgb]

Waiting for my MA1's to come but can you post any support doc's ?
BOM ,
list usable transformers
schematic
??

thanks [ As it turns out they arrived  here today ! ]

 

[ppa]

Waiting for my MA1's to come but can you post any support doc's ?
BOM ,
list usable transformers
schematic
??

thanks

Hi

I am going to send them by email 

Pier Paolo

 

[ppa]

It already has the Germanium transistor in it , that is why you bought it , no ? [ didn't look ? ]
anyway as volker points out [ and confirmed by the picture above ] there is no
swap-able  2520 style DOA footprint

No, it does not use any DOA, moreover, the topology is different respect to the APP2050GE germanium.
MA1 sounds different respect 2050 germanium but both have the "germanium" sound.
Pier Paolo

 

[lotus]

Hi,anyone built one of these yet and how do they sound?
Eric

 

[okgb]

Waiting on transformers for the two kits I bought , but also
bought a couple of the germanium 2520 style opamps from Pier , so
eventually I'll compare the two against each other and a straight 312 pre

 

[ppa]

Waiting on transformers for the two kits I bought , but also
bought a couple of the germanium 2520 style opamps from Pier , so
eventually I'll compare the two against each other and a straight 312 pre

regarding the APP2050GE, it needs the cap in its output since it has bigger input current s than the silicon 2050 and the 2520, because the germanium transistors have a DC gain a lot lower than silicon transistors.

 

[ppa]

Hi,anyone built one of these yet and how do they sound?
Eric

I have put in the market only 8 pieces initially and only recently several MA1 kits,
I have sold several pcs in these weeks, so is a bit hard to find someone Who has finished to assembly one.
But I am sure that two DIY menbers has some MA1's in working condition from several months because they have sent me their (very good) impressions about it.
Maybe Volker (Silent art) has one in working condition.

 

[Pliplo]

Hey Pier, do u know what resistor values i should use with capi's transformers? And what's the correct placement for the AC126?

 

[ppa]

Hey Pier, do u know what resistor values i should use with capi's transformers? And what's the correct placement for the AC126?

C31=220pF    R22=10k

R21 is not used

regarding AC126 I will post a photo very soon 


BTW on reference mark it has its emitter pin, in centre it has the base pin, and the other pin is the collector (in the opposide of the reference mark).

in the MA1  PCB you can find each pin named to place it in right position.

 

[Pliplo]

Hey Pier, do u know what resistor values i should use with capi's transformers? And what's the correct placement for the AC126?

C31=220pF    R22=10k

R21 is not used

regarding AC126 I will post a photo very soon 


BTW on reference mark it has its emitter pin, in centre it has the base pin, and the other pin is the collector (in the opposide of the reference mark).

in the MA1  PCB you can find each pin named to place it in right position.

Ok, so R22=10K and C31=220pF. R21 Is not used. What about R16? (it says 10M or nothing on the BOM, what that does change?). For every other Resistor just follow BOM? (I just ask cause from the kit i got i have 4 extra resistors (2,2k for other germ, 27.5K, 27R and 150R. Not only i dont know where to put them but i dont see a 270R for R30 xD )

As for the AC126, i didnt understand hehe... Just tell me which number to which letter in the PCB =) (see attach)

Thx! And sorry for the noobness