JLM Baby Animal

[Knarleybass]

Knarley Bass - That is a hot looking box!

Yes great neat mounting of the output transformers. Only problem is you somehow seemed to have received the wrong knobs with your kit :wink: :grin:

There were no knobs with the kit... I had those laying around.

 

[martthie_08]

can anyone tell me what the correct orientation of the BD681 transistor is? please click on the image below...



This will be the first of two baby animals. This one has a sowter input and melcor DOA, the other one OEP input and a 990 DOA. Big thanks, Marten

 

[skipwave]

You are correct. See pinout in datasheet: http://www.fairchildsemi.com/ds/BD/BD681.pdf

Viewed from the top (as in your picture), the pins are ECB, Emitter Collector Base. On the PCB, Joe labeled the holes, E on the left and B on the right.

Sowter input.... cool! Good thinking mounting it on its side to leave clearance for the opamp.

 

[martthie_08]

another question before I reinvent the wheel: has anyone done the calculations for the resistor values on a rotary switch for gain control?

 

[Harpo]

[quote author="martthie_08"]another question before I reinvent the wheel: has anyone done the calculations for the resistor values on a rotary switch for gain control?[/quote]
Hi Marten,
dunno if already done before, so take this ms-excel sheet to get the numbers. Just fill in the wanted equally divided steps. :wink:
-Harpo

 

[martthie_08]

wow, nice work! Unfortunately it does not work on office mac, could someone on windows enter 12 in the red field and post a screenshot? That'd be fantastic! Thanks :thumb:

 

[Harpo]

[quote author="martthie_08"]wow, nice work! Unfortunately it does not work on office mac, could someone on windows enter 12 in the red field and post a screenshot? That'd be fantastic! Thanks :thumb:[/quote]
download again :wink:

 

[martthie_08]

fantastic :thumb:

Too bad I already ordered the frontpanel yesterday, I could have done the exact dB scales with your chart.

thanks again, Marten

 

[TornadoTed]

Sorry to be a pain, the CMMI-8PCA's turned up today.

Is the 4 pins with a red dot (pin 1) the primary and the other 4 pins the secondary?

Do I solder all 8 pins so 2&3 and 6&7 are grounded?

 

[skipwave]

[quote author="TornadoTed"]Sorry to be a pain, the CMMI-8PCA's turned up today.

Is the 4 pins with a red dot (pin 1) the primary and the other 4 pins the secondary?[/quote]

Yup.

[quote author="TornadoTed"]Do I solder all 8 pins so 2&3 and 6&7 are grounded?[/quote]

Not grounded, but brought out to the "Ratio" pads, where you install jumpers to set the ratio if your transformer has multiple primary windings..... which it doesn't.

Just one primary, like the JLM14, so no Ratio jumpers. Use a jumper to bring pints 6&7 over to circuit ground.

http://cinemag.biz/mic_input/CMMI-8-PCA.pdf

 

[TornadoTed]

I'm sorry this is my first project and I am not any good with electronics yet, I can solder and 'paint by numbers' but that's about it!!!

So I solder all 8 pins where they go through the PCB and have no jumper fitted where it says low and high next to where the DI would fit.

How do I jump pins 6&7 to a circuit ground?

With some fine wire or something over to the long holes by where it says primary, where I attached the black wire of the JLM14 in the photo a couple of pages back?

 

[skipwave]

[quote author="TornadoTed"]I'm sorry this is my first project and I am not any good with electronics yet, I can solder and 'paint by numbers' but that's about it!!!.[/quote]

No worries. I learn things with each new project and then marvel at just how little I know still. That's part of the fun.

[quote author="TornadoTed"]So I solder all 8 pins where they go through the PCB and have no jumper fitted where it says low and high next to where the DI would fit.[/quote]


Yes.

[quote author="TornadoTed"]How do I jump pins 6&7 to a circuit ground?

With some fine wire or something over to the long holes by where it says primary, where I attached the black wire of the JLM14 in the photo a couple of pages back?[/quote]

I was feeling the deja vu, and sure enough, we did cover this a few pages back. And so, to quote myself... :green:

[quote author="skipwave"]Where the input transformer sits, just below the white circle drawn around the words "primary" and "secondary" (the circle represents the physical space that your Cinemag occupies), there is a spare unlabeled through hole that is intended for the shield pin of an OEP transformer and is connected directly to ground. The Cinemag just has the shield brought out to pin 7 instead.[/quote]

 

[TornadoTed]

So use some wire to connect the pads I've circled?

 

[skipwave]

You got it!

 

[TornadoTed]

Even someone as slow as me gets there in the end!!!

Cheers for all your help Skipwave, much appreciated.

 

[projuice]

Hi my name is junior I'm new to this Forum and also to DIY.
Thanks for all the info I already got from just reading here. With the help of this forum and a good friend of mine I now almost finished my GSSL :grin: :grin:

I started on A BA and a BAD today and I kind of have a question about the BAD.

Can someone tell me if it's possible to run a BAD on two NE5532AP?
And if so what else has to be fitted in that case?

 

[Harpo]

[quote author="projuice"]Can someone tell me if it's possible to run a BAD on two NE5532AP?
And if so what else has to be fitted in that case?[/quote]

welcome to DIY and the Lab. :grin:
All information needed is shown on Joe's site.
The 1st. yellow chart, depending on supply voltage, explains what parts (zener,resistor,transistor) are needed or left out for using NE5532 op-amps.

 

[projuice]

[quote author="Harpo"][quote author="projuice"]Can someone tell me if it's possible to run a BAD on two NE5532AP?
And if so what else has to be fitted in that case?[/quote]

welcome to DIY and the Lab. :grin:
All information needed is shown on Joe's site.
The 1st. yellow chart, depending on supply voltage, explains what parts (zener,resistor,transistor) are needed or left out for using NE5532 op-amps.[/quote]


Ok thanks Harpo!
I've been on that website a million times I dit see the chart for the transformers bur never seen the one with the opamps stupid me!

 

[therecordingart]

[quote author="JimiH"][quote author="Lowfreq"]I can't brag enough!!![/quote]
No no!!! Keep bragging!! I'll be here to listen (well, read...) and pat you on the back. I LOOOOOVE my baby animals on drums too. My only problem is that I want more channels. MORE!!![/quote]

I'm planning on building 4 channels with Cinemag in/out iron and real 2520 opamps. I did the math and you can put together 16 channels for about $4k.

Has anyone built theirs API like with 2520s and cinemag in/out iron? I might need your help very soon. How do they sound? API like?

 

[TornadoTed]

I've built 4 channels with Cinemag input iron, real 2520 but with the JLM 111Dc output iron.

Just getting the cases powder coated, should be up and running in the next couple of weeks.