Topic: Tascam DR-70D 4-channel audio recorder (Part 3)

[groovon]

Add me to the list of potential buyers.  I'd like one like the prototype, but in black if possible.

I'm working on them. No promises yet, but I'll shoot for black anodized if possible.
(I'll also need to get some feedback re the quoted price being somewhere in the ballpark before I go much further.)

thanks
Dave

[voltronic]

I decided to pull the trigger and get the JWMod.  Parts are on their way from Mouser right now, and then it all goes out to the shop for the work to be done.  I'm getting my mod done by a surface-mount shop referred to me by another member.  This shop does not want to be publicly named here, as they don't have time to do lots of these.  Total price with parts, labor, and return shipping looks like it will be around $120 (not including shipping to the shop).

I emailed back and forth with Jim Williams and he gave permission for the specifics of his mod to be posted here since he's not selling it himself.  Cheesecadet had posted some of the details way back in the discussion threads, but I'm thinking that it might be time to put this in the FAQ, along with links to the necessary parts.  Thoughts?  Objections?

[2manyrocks]

Post it.  Would be great to see some before and after photos.

[audBall]

Tascam updated the specs page to include the MID setting:

LOW    +21dB
MID      +36dB
HIGH    +51dB
HI+      +63dB

[voltronic]

Tascam updated the specs page to include the MID setting:

LOW    +21dB
MID      +36dB
HIGH    +51dB
HI+      +63dB

Thanks for the tip.  My test files showed a gain range of 21dB for MID, HIGH, and HIGH+, and 28dB for LOW, but clearly my math was otherwise way off.  For comparison's sake, the old firmware with only 3 ranges came up as a range of 32dB for all 3 ranges.  I'll update the FAQ accordingly.

[groovon]

Post it.  Would be great to see some before and after photos.

Let's cut to the chase--how about a blind listening test: modified vs original? 

Dave

[voltronic]

Post it.  Would be great to see some before and after photos.

I really don't want to crack open my unit, especially since I'm about to pay a professional to do that and don't want to risk breaking something in there first.  The good news is I found some good photos Cheesecadet took of his.

Before:
http://taperssection.com/index.php?topic=170230.msg2130655#msg2130655

After:
http://taperssection.com/index.php?topic=172109.msg2131985#msg2131985

FAQ updated with all of this stuff.

[voltronic]

Post it.  Would be great to see some before and after photos.

Let's cut to the chase--how about a blind listening test: modified vs original? 

Dave

I thought about it, but can't figure out a way to do it in a way that would make the conditions exactly the same in both recordings, and therefore such a test wouldn't be vaild.  I don't think recording with my mics in front of my stereo is going to demonstrate anything real in terms of decreased noise performance.  I suppose I could record myself playing piano before and after, but again there's going to be background noises (fridge running, clock ticking, etc.)  All I can do for sure is test tones from my FP24 or silence / self-noise like I've posted about before.  Anyone else have any ideas?

[2manyrocks]

Piano recording before and after is better than no recording. 

You can always turn off the HVAC and fridge for a few minutes to record. 

Any other 70d owners live near you?

[dallman]

Post it.  Would be great to see some before and after photos.

Let's cut to the chase--how about a blind listening test: modified vs original? 

Dave

I thought about it, but can't figure out a way to do it in a way that would make the conditions exactly the same in both recordings, and therefore such a test wouldn't be vaild.  I don't think recording with my mics in front of my stereo is going to demonstrate anything real in terms of decreased noise performance.  I suppose I could record myself playing piano before and after, but again there's going to be background noises (fridge running, clock ticking, etc.)  All I can do for sure is test tones from my FP24 or silence / self-noise like I've posted about before.  Anyone else have any ideas?

Why would it need to be perfect? Let it run on a source like a piano before and after and lets see if one sounds noticeably better to the masses. What is the harm?

[Ozpeter]

Let it run on a source like a piano before and after and lets see if one sounds noticeably better to the masses.

Define "better"....

Perhaps "more accurate" is what we should be looking for.  And unless you were in the room in the first place listening with your own ears then hearing the recordings, then it would be impossible to judge.  At the end of the day, you have to rely on bench tests as subjective comparisons tend to open up cans of worms.  I don't think we're talking major differences here between before and after - the law of diminishing returns will apply (improving something that's already good into something that's even more good in subtle ways).

[voltronic]

Let it run on a source like a piano before and after and lets see if one sounds noticeably better to the masses.

Define "better"....

Perhaps "more accurate" is what we should be looking for.  And unless you were in the room in the first place listening with your own ears then hearing the recordings, then it would be impossible to judge.  At the end of the day, you have to rely on bench tests as subjective comparisons tend to open up cans of worms.  I don't think we're talking major differences here between before and after - the law of diminishing returns will apply (improving something that's already good into something that's even more good in subtle ways).

That's kind of where I'm at - I don't think anyone is going to hear any significant difference before/after because I don't have a recording studio and the background noise here (appliances, traffic right outside, upstairs neighbors, etc.) will obscure any performance gains.  Also, to record myself playing at level where the levels would be correct, I'd have to set the gain towards the middle / low end so as to not overload and I think the improvements of this mod are really going to show when levels are cranked with a quiet recording.

I agree that measurements are really the only way to make a before/after comparison, and as I've said many times I don't have that capability.  What I can say is that if you look at the specs of the stock opamps and the ones used in the JW mod, there is already a big improvement on paper.  What the poly caps do in terms of performance, I'm not really sure, but Cheesecadet had mentioned they helped HF extension.

[aaronji]

What's the problem with the stock pres?  Noisy?  Overly colored?  I have been thinking about picking one of these up, but, if the stock pres aren't good, I'll pass...I seem to recall some posts saying they sound good?

[pohaku]

I have not seen anyone complaining about the stock pres on any of the boards that I frequent.  And they sound fine to me - at least good enough for rock and roll.  Someone using the DR-70 for classical music or ambient sound may have a different opinion, but I haven't yet seen it expressed.

[aaronji]

That has been my impression from the stuff I have read.  I would like to give this a try, but I record a lot of quiet-ish jazz, so if the pres suck it's not worth it to me.