Help, Rewire tape head signal to output

[fiddler]

Hi all,

I'm new here but i think i have found the place that i've been looking for!

I have a AKAI Mg1214 that i cut my teeth on a decade ago - after spending some dough on the tape mech and using up any extra life i had given it in a couple on months i stopped recording on it and just used it as a mix desk in the rehearsal room.

After a few years i am getting back into things and have gone digital using a yamaha o1x and logic which i find ok. What i would like to do and god know why (maybe let me know if im off track) is route my signals into the mg1214 so i can use the parametric eq's then out to my interface. Problem is the outs onthe mg1214 are before the eq stage - so i had this bright idea of rewiring the signal from just before the tape head to some output jacks and patching that to the digital converters.....

Anyway it sounds like people on the forum have done similar things and i would love to know how? I am good with a soldering iron but am not an electrical engineer!

I have located the 12 (these resprent the tracks) wires that go to the 'record' head on the machine but where to now??? Can these go to 1/4" or xlr or do i need more mods???


Thanks anyone and if you don't think this is worthwhile that would be good advice to!!!!

Michael.

[ironbut]

Hi Michael,
Welcome to the forum.
I'm not sure I'm following exactly what your wish to do.
Do you want to only use the Akai for the eq on board?
I'm not intimately familiar with that unit so if you could outline the signal flow in it that would be great (kinda block diagram it in words).

[fiddler]

OK sorry to be confusing here goes,

signal path of AKAI is:

XLR or TRS in
PRE AMP
Then I have the option to route each channels signal out here:
ACC OUT - 1/4" TRS
ACC IN - 1/4" TRS
Then it continues down the channel strip:
PARA EQ
EFFECT LOOP A
EFFECT LOOP B
PAN
FADER
TO TAPE

I would like to use the pre's and the EQ's on each strip but the only place to pull the signal (of all 12 channels) out is before the eq. I could possibly get 4 channels independently by panning hard left and right and getting 2 from the master then pulling 2 more from the 2 effect loops but i still lose 8 channels....

I thought it may be possible to route all 12 channels to tape (as when recording) but then rewire that signal (prior to the tape head) to go to a set of xlr's or trs jacks that i patch to my digital interface?

Really the problem is that there are no outputs for individual channels after the fader...

Hope someone can help now!!?

Michael.

[Tim]

Refering to a schematic of the unit (or looking inside at the record amp circuit boards), find the record level calibration pots and connect the pot output (the wiper) to your output jacks.   This signal will be post fader and post para EQ.  If there is no audio signal on the pot, then there is a mute transistor (or FET) prior to that pot that needs to be disconnected.  Refer to the schematic for that.

[jcmusic]

Refering to a schematic of the unit (or looking inside at the record amp circuit boards), find the record level calibration pots and connect the pot output (the wiper) to your output jacks.   This signal will be post fader and post para EQ.  If there is no audio signal on the pot, then there is a mute transistor (or FET) prior to that pot that needs to be disconnected.  Refer to the schematic for that.

Hey Tim,
Your the man!!!

Jay

[ironbut]

Kind of an interesting unit. I'd guess the tape format made it kind of tough on the users.
Do you guys know who the target user was for this design? (project studio, broadcast, voice over etc?)

[steveidosound]

Kind of an interesting unit. I'd guess the tape format made it kind of tough on the users.
Do you guys know who the target user was for this design? (project studio, broadcast, voice over etc?)

Tape very similar, but not quite the same as Beta video tape format. I had one that didn't work + a box of blank tapes. At one time I had aspirations of helping people recover/transfer their tracks from every obsolete project studio format, and this was one that was moderately popular but very obscure...

[fiddler]

Hey Tim,

Thanks for getting back to me, I am pushing on with my project.... I have found what i think are the record calibration pots but no schematic.

In the picture I am thinking the first two blue pots from left at the top (2 channels per each of 6 of these boards for 12 channels) the print on the board is 'REC LEVEL'.

Do you think im close to the mark? And if so do I pull an unbalanced signal - ie/ there are only 2 obvious points for connections (ground being the skinny white) that i could solder to a guitar type 1/4"?

These signals are headed for the analogue ins on my yamaha o1x and 1/4" would be preferable - if there is a balanced option i will just use 1/4" TRS jacks instead but there only ever seem to be two leads on this circuit?

I really appreciate your help.

Michael

[Tim]

Those should be the correct pots to obtain the signal you need.  Just connect the pot output to the "tip" terminal of a 1/4" jack.  Unbalanced (hot and ground) is your only option.

[fiddler]

Tim,

Yep those were the ones i used a multimeter and mic first.. there were two options - hot from wiper and ground from a common ground OR a ground that passed through a resistor first.... i tried both and ended up going for the common ground....

Have modded 6 of the 12 channels and they work fine - done a stack of vacumming and panel cleaning (even washed all the knobs in a sock in the washing machine) and put it all back together (goodbye thursday!). Looks like new but ill let you now how they sound later on! Initial tests into headphones seems that they are a little noisy, but the noise can be eq'd so i need to play around a bit more, good to know it's not interference from the tape mech or something....

cheers for the hand again Tim,

Michael

[Tim]

If the signal is a little noisy, it may help to turn the pots up to their max out position.   If you ever intend to use the machine as a tape-recorder again, then first mark where the pots are set to before you turn them up.