here's a crazy question

[sterndrup]

i have a tascam 424 mkiii four track cassette recorder. can i do mods on the preamps...more clean quiet gain? add channel inserts and phantom power?

i have absolutely no electronics experience so I don't think this is something I could do myself, right? are there places that would do something like this?

thanks

 

[mshilarious]

That's funny, a couple of years ago I thought about modding my 424mkII, I bought parts and took it apart then left it sitting in a box.

I don't know what is different about mkIII (I thought that had phantom power?) Ask on the Analog Only or Tascam boards (which are pretty much the same board ) I don't think you'll find a shop to do affordable mods; if you're not up to it, maybe somebody here or elsewhere in DIY-land can help (I can't).

What I remember from mkII: It used 8 pin SIP chips, which are pretty much obsolete. I scored the some of the last stock of 5534 (or 32, can't remember) Mouser had before they ran out. I remember thinking that chip was an upgrade from whatever was stock. So your first task will be locating a supply of the appropriate chip, or using an adaptor board to get a more modern package to fit.

The mkII had no phantom and thus no high-voltage rail. I was gonna tap its positive rail (+16V I think) and use that. No, it's not +48V, if you want that you'll have to go back to the transformer and build a voltage multiplier. But +16V will power a lot of electret condensers, like the Shure SM81, many AT mics, and so forth. So it's worthwhile, I think, and requires a minimum of circuit bending--I needed to cut a couple of traces around the XLR input board, and run a wire and some resistors there. Mind you, I never did that, just planned it.

I was gonna do channels 3-4 as phantom and leave 1-2 unpowered. No particular reason, you could power all of them if you like.

More clean gain? Well, more gain is a function of the opamp feedback network. You can probably change a resistor for more gain, the trick is figuring out which resistor I imagine somebody has a schemo somewhere. I don't remember this unit being particularly noisy, and a quieter opamp will help that.

An insert is simple, just get a switching jack like Neutrik NYS212, and tap the channel right after the preamp. Finding a place to mount the jack on the case will be the trickiest part; it's tightly engineered inside.

Overall, the build quality of the internals I thought was very good.

 

[sterndrup]

wow, thanks for the info. most of it is over my simple head though because I don't have any electronics background to speak of.

the pre's get noisy when jacked all the way up and with no phantom power i'm forced to use my sm57 which i have to jack up and that doesn't even get the signal to the level I want.

thanks again for all the info...sounds like quite a task.

 

[dementedchord]

there are some adapter boards to replace the sip chips... unfortunately i doubt you have the extraroom it takes to mount them...

 

[analog_freak]

Phantom power and 424 MkIII

I had this very thought a few months ago! My solution, given that I have so little electronics experience, was to get a small outboard stereo mic preamp--I only use two condenser mic's at a time, even when doing a drum kit (the coincident and near-coincident patterns work extremely well for recording a drum kit with a good pair of condensers). So I picked up the Audio Buddy by M-Audio.

I haven't yet been able to determine if the M-Audio unit is as good as the Tascam's mic pre's. I simply haven't used the M-Audio enough yet to take a definitive position, but so far it sounds fine. I figure that another advantage to the Audio Buddy is that, for relatively little cost, it's available for multiple recorders, including my 488 MkII (which only has the two non-phantom mic pre's), the Yamaha MT120S (which has zero mic pre's), the 414 MkII (used for mobile recordings), and even the 122 MkIII (my main "live 2-track" recorder).

A further potential advantage (?) is that one could use the sub inputs of the 424 MkIII and have a more direct path to the tape heads, assuming no e.q. is needed.

Cheers,
Michael

 

[Sailjunkie]

I might be missing something, but...

why not just get a cheap Behringer mixer. The Xenyx series mixers have all the stuff you want and you can get a 12 channel for, like, 100 bucks. I record with a lot of instruments, so I'm currently using an MX3482A that I bought off of Craigs list for $350.00. I just run the main outs to the multitrack (Tascam DP02CD) ins and I'm good to go. I'm also using a lot of external effects that I run through the board.

 

[TinNedd]

don't those tascam units have rca ins for mixers and such? Silly that they don't have inserts? Its probably possible to add inserts, but also possible to damage too. They are supposed to be an all in one multitrack recording solution, then again they could have just sold as simply a 4 or 8 track straight rack unit and leave you to workout the preamp side? I sought of think to get the best out of that type medium there should be room there for you to do it the way you want if you choose? Then the otherside they don't allways give you all the outputs too? It just comes right down to this, if Tascam want support for their products, maybe they should show a little more support for the potential customer? Why don't you just record to digital first and then add a layer of analog later? You can do that on any 2 track machine you know Why is this so.....................

 

[mshilarious]

don't those tascam units have rca ins for mixers and such? Silly that they don't have inserts? Its probably possible to add inserts, but also possible to damage too. They are supposed to be an all in one multitrack recording solution, then again they could have just sold as simply a 4 or 8 track straight rack unit and leave you to workout the preamp side? I sought of think to get the best out of that type medium there should be room there for you to do it the way you want if you choose? Then the otherside they don't allways give you all the outputs too? It just comes right down to this, if Tascam want support for their products, maybe they should show a little more support for the potential customer?

Uh . . . the 424 wasn't exactly Tascam's professional offering. They made plenty of reel to reels that are more what you are talking about. And they had to compete with ADAT; at the time most homereccers did not distinguish between analog and digital, we just wanted as many tracks as we could get, but couldn't afford an ADAT. The reel to reel recorders were desirable, but still way too expensive to consider for us poor folk. It wasn't like now where you can find them on eBay and buy them for cheap.

It was targeted as an all-in-one box for the home recording market, which twelve years ago was very, very homey. People didn't worry too much about compressors or inserts or phantom power. Condenser mics were few and expensive. Most people (myself included) just bought the unit and a couple of SM57s. A year later I bought an SM94, which was like $250. It had an internal battery, so I didn't need phantom. The C1000 was also popular for that reason. But the really cheap condenser mic that required phantom didn't exist. An SM81 was like $400, that was a substantial fraction of the cost of the 424.

Anybody would had an effects unit would usually just use it on mixdown. Or you could use the effects send, even for a comp if you had to. But if you start talking about using all four input channels and needing a comp on each channel, well by the time you get to that much gear, most people in that day and age bought an ADAT . . .

 

[Sailjunkie]

Back in my analog days...

I simply ran the right mixer out to my A channel on the tape deck, and the left to B (I was using a Fostex X15). I do the same now with my Tascam DP02. My mixer has 8 effects sends (I am running 3 multi fx units now...Lex LXP15, Lex MX200, Behringer Virtualizer)...I guess what I'm getting at is that the mixer I'm using has pre-amps for all the channels (XLR/1/4" jacks) to handle condenser mics, 1 set if inserts (for my compression unit), all the effects sends and receives I need, and I paid $350.00 for it. Behringer makes smaller mixers with built in preamps/XLR jacks/multiFX for $100.00 (Xenyx 1202FX). I also use a small Behringer preamp sometimes with my guitars (I think I paid $50.00 for it). I'm just wondering why you would need to modify the multitrack unit?