Access-312 Build Thread

[3nity]

ohhhh yeah you're right.
i said that because once you provided me with the right sockets for this..it was when you started...with the ML2520.
sorry for that.

 

[atticmike]

Just finished my 4 channel api box, works perfectly, running at 17.5 V as recommended by 3nity.

Pics asap.

 

[atticmike]

 

[frazzman]

Hey, this might be a no brainer, but I have my finished build here and I wanted to rig up some LEDs for the toggle switches, looking at photos posted here it looks that people have just soldered them to the top prongs of the toggle switch? I've tried all pins but don't seem to get any action... am I missing something obvious??? Thanks in advance

 

[buildafriend]

super cool looking work!

You really have that thing shielded in every way possible. I definitely did not take my shielding anywhere near as serious as you, and mine works great. But hey, yours is built to a very high standard. Congrats on the cool piece.

 

[Jermbob]

So far...

 

[band_master]

hey guys,
so i am back into troubleshooting mode with my one bad channel, and i discovered something potentially interesting while probing around with my multimeter. when checking resistance across the terminals on the polarity switch, i am getting 28.8 ohms on a working channel, while the channel with the low output level is reading 13.6 ohms. does that help narrow it down component-wise? i am pretty confident that my transformers and op amps are good. thanks!

BD

 

[band_master]

so the pot was burned out. i replaced it and was able to get more level, but the sound is distorted and not nearly as loud as a working channel. when i first replaced the pot i was getting the same ohm reading across the pol switch as a working channel, but after turning the unit on i am getting around 13 ohm again instead of 28ohm. another weird thing is that when i engage the pad switch i am getting an increase in ohms across the pol switch terminals closest to the faceplate on the broken channel to about 24 ohm while on a working channel the pad switch drops the resistance across the pol switch to 0.9 ohms. i am thinking maybe i have a bad switch or a burned out trace on the PCB? i am worried that voltage might be getting into the audio pot. any ideas from here? i guess i will try swapping out the pad switch.

cheers,
BD

 

[band_master]

well...still getting the differing ohm reading on the pol/pad terminals but i found a cold solder joint on one of the output transformer wires. tried to reheat it and the pad lifted right off. fixed it with an exacto knife and huzzah! i am getting good volume with zero distortion. only problem now is that the two channels closest to the PSU are a bit louder and distort/hum when you crank them up.

I have swapped around op amps and still get the same effect so i am thinking i need to re-position my PSU away from the audio transformers. maybe have to get a smaller toroidal power xformer and/or a bigger case too. i can see the light!!!



BD

 

[3nity]

Band_master: really weird...they tested out good in my bench. hope you fix it!
Thanks.

 

[atticmike]

super cool looking work!

You really have that thing shielded in every way possible. I definitely did not take my shielding anywhere near as serious as you, and mine works great. But hey, yours is built to a very high standard. Congrats on the cool piece.

#

Thanks

yeah, I tend to get pretty paranoid whenever it comes to grounding / shielding.

Most hilarious mistake I've ever done was to add another coil to the toroidal transformer by hooking up the chassis which ended up being the mysterious more output voltage

 

[3nity]

@ Jermbob...that combination looks killer...pretty sure its gonna sound killer too.
Good luck.

 

[buildafriend]

Jermbob,

I never knew RCA made  DOAs.

Cool.

 

[buildafriend]

How can one best implement a DI for bass guitar and line level signals into an access 312 card?  A Google search lead me to another forum where someone said that one can just inject the signal directly into the op-amp input and the sleeve to ground. I would love to find out that this information is true!!

 

[band_master]

i think this is what you are looking for?

http://www.hansenaudio.se/techpage.htm#API%20312%20mic%20amp%20with%20DI%20input%20modification

 

[buildafriend]

Thanks band master!

Has anyone made a card for this?
http://www.hansenaudio.se/API%20312%20DI%20mod..jpg

 

[Jermbob]

Where would I wire for a jensen jt-115k-e?

 

[Jermbob]

It is
Red - 1
brown - 4
Yellow - 5
Orange - 8

If anyone else want to do this.

White and black go together, or to the ground.

 

[MicDaddy]

8)  I simply cannot wait to hear the RCA Jensen combo that Jermbob has brewing. 

 

[Rellister]

+1


Edit: If he´s willing to post some samples!