Topic: GP DMIC-20 content

[leegeddy]

first thing you may want to do when the UPS man drops off a brand spanking new Graham-Patten DMIC-20 (48kHz version) is to.........

1. open the damn thing up and locate the Analog Devices SSM-2017 mic preamp IC.


2. replace them with the BurrBrown INA-217 mic preamp IC.


3. see how fast you can melt the AD SSM-2017 with a butane lighter.
sorry, no photos.

4. plug in a custom Canare BNC>Coax s/pdif cable


5. think of ways to bug ToddR for tips on Gain Pot mod.

6. feel bummed because i don't have another show coming up until end of December.

marc

[Tim]

so how much do those Burr Brown chips cost?

[leegeddy]

so how much do those Burr Brown chips cost?

$0!! i got 10 samples from TI.com

marc

[F.O.Bean]

nice, thats awesome, i have great 481>dmic tapes from back in the day, they sound great

i can only imagine how that sounds

fwiw, the gain pot mod doesnt look too difficult, you'll have it done in 30 minutes marc

you just need the good dual knobs i believe for some reason, hell, its been 2 years since i considered doing it

[Tim]

that's just silly

nice work Marc... I'm consistently impressed by the quality of your work, that bnc cable is very nice.

[F.O.Bean]

here marc

http://www.taperssection.com/yabbse/index.php?topic=23659.0

[F.O.Bean]

also marc, those IC's just snap in right?

that looks hella easy

[leegeddy]

also marc, those IC's just snap in right?

that looks hella easy

yes. you can jiggy the old one loose and snugly pop the new ones in. 

thanks for the link!! he's got a much better pic of the SSM2017. the DIP sockets mounts are so easy to use.

thanks tim, much of the construction's basically done by the Canare's parts. great quality stuff for pro-use.



marc

[Swampy]

I was thinking about selling my DMIC, because its just not warm enough for my tastes with the TLs. But this idea of replacing the pres is definitly interesting to me. Are these BurrBrown pres in anything else? Do you think it would be possable to warm this puppy up at all? Id appricate any info! Thanks!

[leegeddy]

I was thinking about selling my DMIC, because its just not warm enough for my tastes with the TLs. But this idea of replacing the pres is definitly interesting to me. Are these BurrBrown pres in anything else? Do you think it would be possable to warm this puppy up at all? Id appricate any info! Thanks!

alex;

i've replaced the mic pre IC in my mv100s and the difference was noticeable (but not like night/day). it's cleaner, lower noise floor. it doesn't change the tone (warm, presence, transparent, etc.)  i would think that changing op amps along with other parts would achieve the overall coloration change of a preamp.

marc

ps. TL>BurrBrown mod DMIC-20 is exactly what i'll be running too

[Swampy]

Hmmm... Ill be interested to hear what you think, to me its just has no balls Maybe I should try the mod to just for the hell of it, doesnt look hard...

[leegeddy]

Hmmm... Ill be interested to hear what you think, to me its just has no balls Maybe I should try the mod to just for the hell of it, doesnt look hard...

i will certainly lyk. i'm hoping to tape STS9 in Dec with the setup.

yep. changing IC is a total breeze with those DIP sockets in place.

marc

[Swampy]

very cool, Ill be interested to hear what you think. Where does one get thoes ICs?

[Todd R]

first thing you may want to do when the UPS man drops off a brand spanking new Graham-Patten DMIC-20 (48kHz version) is to.........

1. open the damn thing up and locate the Analog Devices SSM-2017 mic preamp IC.

2. replace them with the BurrBrown INA-217 mic preamp IC.

3. see how fast you can melt the AD SSM-2017 with a butane lighter.
sorry, no photos.

4. plug in a custom Canare BNC>Coax s/pdif cable

5. think of ways to bug ToddR for tips on Gain Pot mod.

6. feel bummed because i don't have another show coming up until end of December.

marc

Just for the record, the Todd R that does the gain mods on the DMic20 is not me -- different Todd R from the DC area.  I'm pretty sure he's on this board, but I don't know his handle.

Marc -- good to hear you've tried out the INA217s instead of the SSM2017s.  I always felt the MV100 and DMic20 that uses them were a bit harsh in the high end.  Did you ever notice this and do you think the INA217 replacement smoothes out the high end at all?

[leegeddy]

very cool, Ill be interested to hear what you think. Where does one get thoes ICs?

here ya go.

http://www.ti.com/ goto Samples link.

INA217AIP

marc

[leegeddy]

first thing you may want to do when the UPS man drops off a brand spanking new Graham-Patten DMIC-20 (48kHz version) is to.........

1. open the damn thing up and locate the Analog Devices SSM-2017 mic preamp IC.

2. replace them with the BurrBrown INA-217 mic preamp IC.

3. see how fast you can melt the AD SSM-2017 with a butane lighter.
sorry, no photos.

4. plug in a custom Canare BNC>Coax s/pdif cable

5. think of ways to bug ToddR for tips on Gain Pot mod.

6. feel bummed because i don't have another show coming up until end of December.

marc

Just for the record, the Todd R that does the gain mods on the DMic20 is not me -- different Todd R from the DC area.  I'm pretty sure he's on this board, but I don't know his handle.

Marc -- good to hear you've tried out the INA217s instead of the SSM2017s.  I always felt the MV100 and DMic20 that uses them were a bit harsh in the high end.  Did you ever notice this and do you think the INA217 replacement smoothes out the high end at all?

todd;
ahhh seee. thanks for the clarification.

as for the INA217 vs. the SSM2017, i immediately noticed the clarity and the lower noise floor in my recordings.  perhaps the clarity was due to the smoothness in the highs, but i didn't pick up on the "smoothness" aspect of it immediately.  i just lumped the sonic difference as "clarity". 

what op amp is a good replacment for the OP275?  the slew rate on the OP275 is not too high.

thank you for much of the inspiration to my DIY bug
marc

[blu666z]

I really have no clue what I'm talknig about so telll me to shut up if I say something stupid but...

Does it matter which direction resistors are oriented?  ie.  Is there there a definte input and output side?

If you look at the resistors below the longer chip in the middle of the photo, starting at the blue thing counting toward the outside, the third resistors on each side are turned opposite of each other.  All the rest seem to be oriented the same.  Again, tell me if I'm way off.

-Kevin

[Todd R]

Resistor orientation does not matter.

[F.O.Bean]

and all the pretty colors on the resistors just tell their size/handling capacity

[Swampy]

Hey, so thanks for the suggestion Marc, I just did the mod (if you can call it that, it was so easy!) What do you guys think I should list the DMIC as now on the txt fles? somthing mod DMIC-20? Help. THANKS!

[Brian]

ICmod DMIC-20 ?

[Brian]

oh and +t's all around for the great thread BTW.  lots of great info here

[leegeddy]

oh and +t's all around for the great thread BTW.  lots of great info here

indeed, +t all around for a great discussion.

i've listed mine as: BurrBrown mod GP DMIC-20......

both my Beyerdynamics have been modded as well and i simply refer them as "BurrBrown mod....."

marc

[Chuck]

Hey, so thanks for the suggestion Marc, I just did the mod (if you can call it that, it was so easy!) What do you guys think I should list the DMIC as now on the txt fles? somthing mod DMIC-20? Help. THANKS!

Alex:

Can you report any noticable difference in the sound of your DMIC-20 with the mod?

[Swampy]

Hey, so thanks for the suggestion Marc, I just did the mod (if you can call it that, it was so easy!) What do you guys think I should list the DMIC as now on the txt fles? somthing mod DMIC-20? Help. THANKS!

Alex:

Can you report any noticable difference in the sound of your DMIC-20 with the mod?

I haven't taped a show in the last six hours I'll definitely let everyone know after Hookah on Saturday.

[F.O.Bean]

excellent alex

[Simp-Dawg]

i got my chips, but i still think there's a problem with my dmic20...in fact i'm pulling it off the auction block.  i'm only getting around 5v or so on the xlr's, not the full 48v i need...

[dr.ph0b]

i got my chips, but i still think there's a problem with my dmic20...in fact i'm pulling it off the auction block.  i'm only getting around 5v or so on the xlr's, not the full 48v i need...

sounds like your phantom power maybe horked?

[Simp-Dawg]

yeah i'm pretty sure that's the problem right there...i should test it with an external phantom supply to be sure the levels are hot enough with the proper voltage....

[wbrisette]

Hey, so thanks for the suggestion Marc, I just did the mod (if you can call it that, it was so easy!) What do you guys think I should list the DMIC as now on the txt fles? somthing mod DMIC-20? Help. THANKS!

I'm not sure this really qualifies as a mod, at least not the extent that it needs to be noted in lineage. To me this is like listing cables, it's not something that really matters in the end. Since exchanging the chips really only helps lower the noise floor and doesn't change the sound quality, I don't see where it helps, but that's just me.

Wayne

[Todd R]

Hey, so thanks for the suggestion Marc, I just did the mod (if you can call it that, it was so easy!) What do you guys think I should list the DMIC as now on the txt fles? somthing mod DMIC-20? Help. THANKS!

I'm not sure this really qualifies as a mod, at least not the extent that it needs to be noted in lineage. To me this is like listing cables, it's not something that really matters in the end. Since exchanging the chips really only helps lower the noise floor and doesn't change the sound quality, I don't see where it helps, but that's just me.

Wayne

I don't think I agree with you here.  All chips -- esp op amps -- have their own signature on sound.  (BTW, the SSM2017 and INA217 are basically glorified op amps, op amps plus some auxilliary transistors to round out a "preamp on a chip" all put together in one piece of silicon.)  You can't really say all that is happening is that you are lowering the noise floor.  By changing out the gain chip the signal goes through, you will change the signature sound of the preamp. 

I'm pretty sure all Doug Oade does with making the modSBM1 is to change out the op amps.  At least, that is the change that is responsible for the majority of the mod that results in a different sound for the SBM1.  With the w-mod and p-mod UA5's he changes the op amps and replaces some of the capicitors in the signal path.  Bottom line though, most of what we already label with "mod" status is the result of changing out a few components in the signal path.  This may only be reflected in the published "specs" as a lower noise floor (or perhaps a faster slew rate or something of the like), but changing the components in the signal path does change the sound in a more basic way than just lowering the noise floor.  I'm sure lots of people will comment on how the sound of the stock SBM1 differs from the Oade mod SBM1.  (Ok Makers Marc, time to jump in and help me out here.)

I've always heard a harshness in the high end with all the preamps that use the SSM2017 chip -- the DMic20, the MV100, and the PSP3.  I'm interested to hear whether changing the SSM2017 to an INA217 alleviates this harshness.

[Tim]

maybe it would make the psp3 worth that hefty price tag

[F.O.Bean]

so has anyone actually tried out their mod-dmic20's??

[wbrisette]

I don't think I agree with you here.  All chips -- esp op amps -- have their own signature on sound.  (BTW, the SSM2017 and INA217 are basically glorified op amps, op amps plus some auxilliary transistors to round out a "preamp on a chip" all put together in one piece of silicon.)  You can't really say all that is happening is that you are lowering the noise floor.  By changing out the gain chip the signal goes through, you will change the signature sound of the preamp. 

In theory I agree with you, but unless there is some improvement, or changed sound it's a moot point. Again I liken it to when people list cables. If you're Eric Johnson and you can tell the polarity of a wire (he claims he can), then maybe cables make a difference, but most of the time it's a waste.

I'll eat my words if the change makes a world of difference. (hmmmm, yummy).

BTW, has anybody thought about putting in the THAT 1510 chip? While not shipping yet, it looks like it might be better than the BurrBrown.

Wayne

[wbrisette]

Folks should check out:
http://recording.org/users/kev/kdmp.htm
http://recording.org/users/kev/kdmp.htm

Looks like somebody has already done some A/B testing.

Wayne

[F.O.Bean]

only vocals tho, whos gonna be the first to a/b some live environment stuff

[(((KB)))]

^ I know this is waaayyy old, but did it work for anyone?

-K

[Kyle]

^ I know this is waaayyy old, but did it work for anyone?

-K

did you mod yours?

[(((KB)))]

^ I know this is waaayyy old, but did it work for anyone?

-K

did you mod yours?

No, not yet.

Checked into it w/ an engineer friend of mine and he said to do it because the BurrBrown IC's have better specs. It's not going to make it a V2 or anything, but should have better results that the stock IC's.

For a "second opinion", I asked Richard (PoorlyConditioned) about this upgrade. He said he did this upgrade with "THAT Semiconductor" IC's instead of the BurrBrowns. He said that he didn't really do enough tests to know if it improves or not, but thinks the stock setup is quite good, anyway.

I'm told that the "THAT" IC's (1500's???) are better than the BurrBrowns, but you have to purchase them... $2 something and a min order of 50 so, I settled for the free BurrBrowns. I ordered free samples following the information in this thread. Planning on doing the swap this week since I'm rolling for MMW/SCO in Philly on Saturday.  Whether or not you hear the difference is another story... depends on playback system to really hear a difference I would assume. Planning on doing a quick A-B test w/ a test tone generator or something when I get them...replace only the left channel and leave the right alone to do the test, then install the other after. It will be intersting to hear if there's a difference.

-Kevin

[(((KB)))]

^ I know this is waaayyy old, but did it work for anyone?

-K

did you mod yours?

Did the upgrade test today... (re-recorded a random show dual mono w/ the upgraded L channel and the stock R channel)... I can say for certain that it didn't degrade the quality. Seems to have made it slightly better... tough to hear it on my playback system. I need some good cans to really tell for sure. Going to pass the test file on to my friend that has audio analysis software, so he'll be able to tell me for sure.

-Kevin

[F.O.Bean]

i always liked my dmic-20 stock, butw anted to try the mods before i sold it

i would be more interested in the gain pot mod than anything

[(((KB)))]

i always liked my dmic-20 stock, butw anted to try the mods before i sold it

i would be more interested in the gain pot mod than anything

One of my pre's has that trim pot mod done to it, but it's sooo sensitive... I'm afraid to really use it. I like the just plain dip switches actually, much easier to keep the channels even.

Tossed around the idea of having the dipswitches taken out and replace w/ potted potentiometers, but I don't think Nick Z. wants to do it since he said it was a pain in the ass... oh well.

I'm pretty satisfied w/ the the IC test I did, so I decided to do the BurrBrown upgrade to both pre's I have. The faster chip seemed to pass through more detail overall and make the highend a little less harsh.

-K

[tubehead]

got a chance to listen to bird's INA217 version in a blind A/B, it pretty much followed my hunch, the stock ICs sound a bit harsh on the top end, the 217 is smoother in general but especially on the high end, definitley worth the $10 or whatever you have to put into it....

those dmics seem to be plenty moddable, it should be possible to make an adapter board and cobble in an INA103, the same part used in the V2/V3. i'm not a big fan of GP in general, after tearing one of those things down (and seeing the HORRIBLE gain pot mod that who-the-fuck-ever put into it) it seems most of it is pretty consumer-ish or prosumer/broadcast quality. no drooling over the part selection etc. the adc is a crystal semi which doesn't wow me either...i'm about to get an ad20 (with an AKM adc, my favorite!) and mod the hell out of it...anybody know what's in those>??

[poorlyconditioned]

got a chance to listen to bird's INA217 version in a blind A/B, it pretty much followed my hunch, the stock ICs sound a bit harsh on the top end, the 217 is smoother in general but especially on the high end, definitley worth the $10 or whatever you have to put into it....

those dmics seem to be plenty moddable, it should be possible to make an adapter board and cobble in an INA103, the same part used in the V2/V3. i'm not a big fan of GP in general, after tearing one of those things down (and seeing the HORRIBLE gain pot mod that who-the-fuck-ever put into it) it seems most of it is pretty consumer-ish or prosumer/broadcast quality. no drooling over the part selection etc. the adc is a crystal semi which doesn't wow me either...i'm about to get an ad20 (with an AKM adc, my favorite!) and mod the hell out of it...anybody know what's in those>??

The front end of the AD20 isn't very nice IMO.  It has a differential transistor pair, then into a standard opamp, either MC33079 or INA something.  Normally this would be OK, but I don't think the transistor front end is very well done.  It *does* have low noise, but my opinion is that it sounds "flat", lacking detail.  I would stick with the DMIC20, since it has +/-12V in there, and you could put in practically any front end you want.

  Richard

[(((KB)))]

Rolled (w/ the BurrBrown DMIC-20) for Blues traveler last night at a local venue where I frequently record. I def. think the recording sounded better with the upgrade.   

Much thanks to all who made posts on this thread.

-K