rechipping a tascam m3500

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I have one of these consoles anyway i found this thread on rec.audio.pro made for some intresting indeed

if you dont want to waste time searching here use this search method go to the link i leave for you here it is


http://www.tweakheadz.com/the_buzz_r...he_street.html

go to third in the list left hand side current news at rec.audio.pro
click that thentype in this rechipping my board read parts 1,2,3 and anything else on the m3500 it shows what can be done with a little know how lots of info on op amps here

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typos grrrrrrrrr intresting reading

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heres a lil taste of some of this post i loved reading this whole posttook ages but i gained heaps of info from this for fixing my console

[QUOTE]Please see my previous "rechipping" themed threads for the pertinent history.

Part 3

I've completed the process of replacing all the Linear Technologies 1358 "high
speed" opamps installed by Audio Upgrades in my
never-gonna-call-it-a-Tascam-M3500-again-now-I-call-it-"custom" console with
various Burr Brown chips. As stated in previous posts, after becoming
thoroughly disenchanted with the LT1358s I began experimenting with
alternatives. I've now replaced all the input strips (5 dual opamps each
including the mic pre) with Burr Brown OPA2604APs. These cost $1.80 each bought
in quantities of 100 or more (I used 160). As stated previously these chips
have a great sound and do appear to be fully compatible and functional under
the circumstances, showing none of the oscillation tendencies I was warned
about (at least as far as my ears can tell - I haven't used a 'scope). The
program busses and last-stage outs to 2 buss were fitted with OPA2132Ps ($6.91
apiece). The first-stage 2 buss and control room outs were fitted with 2604s.

Some thoughts:

Like fucking *wow*! This board is slammin'! Seriously, the console sounds just
amazing now. The 2604s give the heart of the console (the input section) a
really satisfying combination of warmth, clarity and depth that is entirely
unlike the original stock sound or the original Audio Upgrades sound. I'm able
to get the kind of kicking low end and depth that was so sorely absent with the
1358s and the clarity and imaging that was unobtainable with the stock chips.
While my impressions must be taken as preliminary (I just completed the
installation yesterday) I feel quite confident that this puppy will definitely
sit up and bark when papa says bark <g>. One thing I'm noticing to my
unexpected delight is the tendency of the 2604s to react a bit like tubes when
overdriven. In other words, when intentionally turning up gain trims or
overfeeding the inputs via an outboard limiter or whatever, the chips don't go
all "hashy" and transistory as they distort. Rather, they quite calmly begin to
"fold in" the top end and seem to compress the mids in a surprisingly smooth
way. I've found this to be a very useful crayon in my coloring box as I've
experimented with some fairly gritty electric guitar sounds. Crank it up into
overload a bit and the grit smooths right out. Really cool. I must say that in
regard to this, Tascam did a nice thing by offering a metering switch that will
show post-eq level on all channels. This enables me to view exactly how hard
I'm hitting the channel and is a feature I've always used to manage headroom
issues. I wish all consoles showed this - most just show tape in.

I arrived at the decision to use the BB2132Ps in the busses and the 2 buss outs
because it seemed that too many stages of 2604s were clouding things up a bit.
The 2132s are less tubby in the lower middle and have a more extended and
really solid low end, and although they are a bit shallower sounding than the
2604s the combination seems to work very well.

While my test mixes over the last day or so with the fully rechipped console[QUOTE]

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a little later on in the piece this guy runs tests on his console after all the mods were done and heres what he finds at this stage he is arguing with someone eho is telling him its all too good to be real

[QUOTE]Ok sorry for losing my patience. After signing of I said to myself "well what
the hell let's run full scale sine waves through the sucker".

So I did.

The setup:
Loftech TS-1 sweep oscillator set to -7.8 dbm (nominal -10 level as I
understand it - the operating level of the console), initially at 1 Khz.

Tone patched directly into a variable line input of the console (line in
includes all input opamps - "tape" in skips one). Eq bypassed, hi pass filter
out.

Tone level set using fader, pan and trim pot for exact 0 db VU reading on both
console 2 buss meters with stereo buss master fader set for unity gain.

After sweeping the oscillator, the results:

+0/-.7 db (that's *point* 7) from 15hz to 29Khz both channels.

At 29Khz (the upper limit of the TS-1): -.2db both channels.

At 20 Khz: flat left, so-damn-close-to-flat right I don't know what to call it.
Say maybe -.1.

At 15Khz: Like the Bonneville Salt you-know-whats.

At 10 Khz: Like a day-old glass of beer

At 500 Hz: What's the opposite of Dolly Parton's chest type?

At 250 hz: Another four letter word beginning with f that your parents didn't
object to.

At 100 Hz: What your Ford Explorer tires look like if you're unlucky.

At 50hz: Minus a frickin' hair both sides equally.

At 30 Hz: -.3db both sides

At 16 Hz (the low limit of the TS-1): The meters flutter visibly at this
subsonic frequency but I'd say it's about -.7 both channels.

This is not surprising to me. While I can't hear 29K or 15 Hz, it confirms what
I did hear: a very high fidelity signal path.

*Now* let's give it a rest.





Ted Spencer, NYC [QUOTE]

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last post if any of you want to read on go to the top of the page and follow instructions

[QUOTE]Subject: Re: the ongoing saga of my tascam m 3700
Newsgroups: rec.audio.pro
View: Complete Thread (6 articles) | Original Format
Date: 2000-10-25 14:47:02 PST


An addendum to my previous post (as if it weren't long enough already), for
comparative purposes, using the same measurement setup as before:

(All pre/comp/eq units set to line in, all equalizers, filters or compressors
bypassed)

M3500 tape in to channel direct out, fader at unity: -84db. One channel to
stereo buss (all other channels de-assigned): -83db. All 32 channels asigned to
stereo buss and all 32 faders at unity gain: -74db. The -84db figure was
obtained in the most comparable manner to the other tests below (only one
channel measured).

Millenia STT1 "Origin", $3000, tube mode, input and output at 2 o'clock,
unbalanced out: -79db. Same in solid state mode: -88db.

Neve 1099 (same as 1073), $2650 from Brent Averill, unbalanced, output level
set to approximately -10dbV nominal: -84db.

Avalon VT-737sp, $1950, input and output at detents (12 o'clock): -82db

Phillips CDC 935 CD player, unbalanced out, no disc: -82db.

Tascam DA-88, unbalanced out, repro, 48k, no tape: -82db.

Adat, blackface, unbalanced out, repro, no tape: -84db.

Digidesign 888/24, mix cards on (in expansion chassis) computer off: -83db.

Panasonic SV3700 unbalanced out, 44.1k, no tape: -84db.

This is to illustrate the specific conditions of this test and its variance
from published noise figures (such as "better than 92db" on the DA-88). It is
most likely due to different test conditions and standards. It would seem to
suggest that my M3500 as it exists is not excessively noisy by comparison.

[mixmkr]

who are you talking to? sounds like you're enjoying your 3500, anywayz

[trebles]

those posts were left for anyone who is intrested if you take a closer look you will find out how great this upgrade actually is