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D.A.V. BG1 vs AEA TRP ??
Old 1st July 2015
  #1
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Lorenzop's Avatar
 
🎧 5 years
D.A.V. BG1 vs AEA TRP ??

I almost know Plush's mantra by heart about the DAV by now

BUT

Can anyone comment about real world situations especially with Ribbon mics? Does the TRP really add that something extra with that high impedance thing going on?

Also, is the DAV 501 module the same as the BG1U sound wise/headroom wise??

Cheers!
Old 1st July 2015
  #2
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rumleymusic's Avatar
 
1 Review written
🎧 10 years
As far as the DAV 500 series vs the BG1. They are chip amps that run on 18 volt rails, so they are not as power hungry as, lets say, Forssell's preamps, which are what the AEA's designs are based on. They should perform the same. AEA's TRP amp is mainly extra useful for the 83 dB of gain, which the DAV does not have. I would look at the AEA 500 series amps which include a tilt EQ to compensate for Ribbon HF rolloff.
Old 1st July 2015
  #3
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Tommy-boy's Avatar
 
🎧 10 years
I have not had the pleasure of using DAV's, so I can't comment on both. However, I have a TRP - miles of very clean (but not sterile) gain.

-Tom
Old 1st July 2015
  #4
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Lorenzop's Avatar
 
🎧 5 years
Yes the AEA 500 module is based off the RPQ I believe?
In any case 2 of them would cost double the 2 channel DAV... :(
Is that extra gain really useful? I mean, can't one bring up the gain a bit in the DAW afterwards using a Dav ?
Old 1st July 2015
  #5
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The AEA and the DAV have a different kind of sound. Both very good, just different. The AEA I find cleaner in a Grace-ish kind of way, the DAV has some subtle color to it. I tend to think of the DAV as having the same sort of subtle color a Schoeps omni has compared to say, a DPA or Josephson omni. But again, both are very high quality, very accurate. And IIRC you can order your DAV direct with customized gain settings, if you need a gain range similar to what the TRP offers.
Old 1st July 2015
  #6
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Lorenzop's Avatar
 
🎧 5 years
Thanks Kevin very useful description.

Have you used the DAV with ribbons and what did you think? How much gain?
Old 1st July 2015
  #7
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hbphotoav's Avatar
 
🎧 10 years
I've had more problems with RFI/EMI (one downtown NashVegas venue in particular) on long runs with ribbons (SF12 and Fat Heads) than with the D.A.V. or Apogee Ensemble channels simply supplying "enough" clean gain. I've been really pleased through the years with both, though the nod for principal pair(s) goes to the BG8. Never a problem (other than user error) with it and M296s, MKH8040s, 4061s or TLM193s. Nor with it and SF12/Fat Heads through short (25'/8m) cables.

HB
Old 2nd July 2015
  #8
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king2070lplaya's Avatar
DAV is amazing with ribbons. The high impedance on the inputs really brings out the character and life of the mics. Even a simple, cheap ribbon like a Beyer m130 sounds like a new mic through the DAV.
Old 3rd July 2015 | Show parent
  #9
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potscrubber's Avatar
 
🎧 15 years
Quote:
Originally Posted by hbphotoav ➡️
I've had more problems with RFI/EMI (one downtown NashVegas venue in particular) on long runs with ribbons (SF12 and Fat Heads) than with the D.A.V. or Apogee Ensemble channels simply supplying "enough" clean gain. I've been really pleased through the years with both, though the nod for principal pair(s) goes to the BG8. Never a problem (other than user error) with it and M296s, MKH8040s, 4061s or TLM193s. Nor with it and SF12/Fat Heads through short (25'/8m) cables.

HB

I've become attached to the use of Beyer M160's for timpani overheads for classical, and as stage "room" mic's for amplified shows. I've got a TRP, but have too struggled with RFI/EMI in most venues with the M160's (not pointing blame at TRP). My works-every-time solution, is to put the humble Sound Devices MM-1 or MP-1 at the bottom of each M160 mic stand. Battery powered, enough gain, and zero RFI/EMI issues.

Actually, if anyone in Australia wants to buy an AEA TRP, pm me.

Last edited by potscrubber; 4th July 2015 at 12:10 AM..
Old 3rd July 2015 | Show parent
  #10
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🎧 10 years
Quote:
Originally Posted by king2070lplaya ➡️
DAV is amazing with ribbons. The high impedance on the inputs really brings out the character and life of the mics. Even a simple, cheap ribbon like a Beyer m130 sounds like a new mic through the DAV.
What is the input impedance of the DAV?
Old 3rd July 2015
  #11
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king2070lplaya's Avatar
Hi Kevin
glad you like the amp!
the input impedance is 20 K ohms
regards
Mick
----- Original Message -----
From: Kevin Bourassa
To: Mick Hinton
Sent: Wednesday, March 30, 2011 10:11 AM
Subject: Re: Fw: Dav BG2

Hey Mick,

Got the BG2 a little over a week ago. Sounds great! Just out of curiosity, what is the input impedance on this preamp? Thanks!

Kevin
Old 4th July 2015 | Show parent
  #12
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🎧 10 years
Quote:
Originally Posted by king2070lplaya ➡️
Hi Kevin
glad you like the amp!
the input impedance is 20 K ohms
regards
Mick
----- Original Message -----
From: Kevin Bourassa
To: Mick Hinton
Sent: Wednesday, March 30, 2011 10:11 AM
Subject: Re: Fw: Dav BG2

Hey Mick,

Got the BG2 a little over a week ago. Sounds great! Just out of curiosity, what is the input impedance on this preamp? Thanks!

Kevin
no need to acquire the TRP then!
i thought it was 1,5kohm
Old 4th July 2015
  #13
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Lorenzop's Avatar
 
🎧 5 years
Me too
Are we sure that 20K figure is accurate? Where did you get it from
Old 4th July 2015
  #14
Someone will need to explain how adding a pair of 6.81k phantom feed resistors to the mic preamp's input won't lower the input impedance to below 6.81k ohms?
Old 5th July 2015
  #15
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ISedlacek's Avatar
 
1 Review written
🎧 15 years
DAV has a bit of extra "colour" - a kind of "sweetish", very slightly compressed as if, with a touch of extended low end. TRP is straight clean, but less sophisticated and less amazingly full open sounding than SMP-2 preamp (both are Fred Forssell's designs). I much prefer SMP-2, but the price is different too ...
Old 3rd March 2021
  #16
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🎧 10 years
Revisiting this thread to determine how well suited the DAV BG8 ( or BG1 stereo mic pre) is for ribbon mic use, with respect to input impedance ?

The designer/mfr's statement to this question by Kevin Bourassa (post no.11 above) is 20k, but Jim Williams questions this...are there any concrete reasons for doubting Mick Hinton's 20k ohm declaration ?

The manufacturer specs omit this item: http://www.davelectronics.com/bg8.htm

By way of comparison, another manufacturer of a dedicated ribbon mic preamp (Integer Audio RMP-2) outlines how input impedance affects ribbon mic performance:

Design philosophy: https://www.integeraudio.com/about.html

Specs: https://www.integeraudio.com/rmp2-preamp.html

A relevant aspect (according to Integer Audio) :

"The typical modern ribbon microphone output impedance is 250-300 ohms. The input impedance should be about 10 times the microphone's impedance to reduce “loading” and maximize voltage transfer. If the microphone output and the preamp input impedance were equal, the input signal would be attenuated by –6dB and the S/N ratio 6dB worse.

If the preamp input impedance is too low the microphone may become unduly loaded, add distortion and sound "thin". Preamp input impedance must also account for the microphone's electronic damping requirements.

If the input impedance is too high the microphone may become under-damped or cause issues related to microphone transformer resonance. This can result in some frequencies being hyped or exaggerated. The end result should minimize signal loss, lower distortion, and provide an accurate microphone frequency response"

The Integer Audio's RMP-2 ribbon mic preamp's input impedance: "Differential input impedance is 30k ohms fixed"

10 times the typical ribbon mic impedance would give around 3k ohm....which begs the question: 'What is a desirable or optimal mic preamp input impedance figure/range:..2-3k ohm, or 20-30k ?"

By way of comparison the AEA TRP2 ribbon mic preamp has the following spec:

"The sound and tonality of dynamic microphones like ribbons and moving-coils are directly affected by the impedance of a preamp. The higher the impedance, the better the sound. The TRP2 boasts an extra high input impedance of 63K Ohms.

Preamps with an impedance of under 10k ohms will limit the lows, highs, and transients of your passive microphones. The TRP2's high impedance will reveal your microphone’s true nature– a thick low-end, open top-end, and articulate transient response that you will need to hear to believe. Both condensers and active microphones will also benefit from the TRP2's impedance"

Finally, a Sound On Sound review of the original TRP states:

"Ribbons are particularly critical in this regard and the AEA TRP provides an enormously high input impedance. Depending on which set of published specifications you believe, it is either 18kΩ or 30kΩ. Both are extremely high in comparison to most modern preamps, which are about 2kΩ "

Last edited by studer58; 3rd March 2021 at 01:44 PM..
Old 3rd March 2021
  #17
Those SSM 2017, that 1510 and BB INA217 mic preamp chips are all designed to have 10k ohm input loading resistors. You can up that to 20k ohms. Once you add the 6.81k phantom resistors that drops to 4.5k input impedance.
Old 3rd March 2021 | Show parent
  #18
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🎧 10 years
Quote:
Originally Posted by Jim Williams ➡️
Those SSM 2017, that 1510 and BB INA217 mic preamp chips are all designed to have 10k ohm input loading resistors. You can up that to 20k ohms. Once you add the 6.81k phantom resistors that drops to 4.5k input impedance.
Thanks Jim....if that figure is the typical ceiling impedance for the DAV (and likely many other regular preamps supplying phantom power), then the question remains whether that's a suitable or sufficient input impedance for typical ribbon mics ?

If the Integer Audio recommendation of 10x the typical ribbon mic range (200-300 ohm) is correct, then 4.5k should be ok ?
Old 4th March 2021
  #19
4.5k has worked here for decades. It's a light load for most mics.
Old 5th March 2021 | Show parent
  #20
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🎧 10 years
Thanks Jim....that’s reassuring. Those dedicated ribbon preamps with 20-30k impedance often have transformers in their architecture as well, which many ‘all round’ pre’s don’t.
Old 5th March 2021 | Show parent
  #21
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🎧 15 years
Quote:
Originally Posted by studer58 ➡️
Thanks Jim....that’s reassuring. Those dedicated ribbon preamps with 20-30k impedance often have transformers in their architecture as well, which many ‘all round’ pre’s don’t.
The Gordon preamp has no transformers but 2 Mohm input impedance and plenty of quiet gain.
Old 5th March 2021 | Show parent
  #22
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🎧 10 years
Quote:
Originally Posted by Folkie ➡️
The Gordon preamp has no transformers but 2 Mohm input impedance and plenty of quiet gain.
That sounds like it's tailor-made to plug an acoustic guitar piezo-transducer pickup, or a Fender Stratocaster, directly in...like a Radial DI box.

What's a mic preamp doing with an input impedance so high...is there some theoretical or practical advantage to that ?

http://www.gordonaudio.com/

It appears to challenge the assertion from Integer Audio regarding the input impedance for their dedicated ribbon micpre (copied from post #16 above):

"The typical modern ribbon microphone output impedance is 250-300 ohms. The input impedance should be about 10 times the microphone's impedance to reduce “loading” and maximize voltage transfer. If the microphone output and the preamp input impedance were equal, the input signal would be attenuated by –6dB and the S/N ratio 6dB worse.

If the preamp input impedance is too low the microphone may become unduly loaded, add distortion and sound "thin". Preamp input impedance must also account for the microphone's electronic damping requirements.

If the input impedance is too high the microphone may become under-damped or cause issues related to microphone transformer resonance. This can result in some frequencies being hyped or exaggerated. The end result should minimize signal loss, lower distortion, and provide an accurate microphone frequency response"

The Integer Audio's RMP-2 ribbon mic preamp's input impedance: "Differential input impedance is 30k ohms fixed"


It seems likely that different design parameters relate to condensor mic preamps ...perhaps ?
Old 5th March 2021 | Show parent
  #23
Lives for gear
 
🎧 15 years
Yes, you can plug an instrument directly in.
Willie Weeks, the bass player uses a Gordon this way.
The high impedance input unloads the microphone and maximizes voltage transfer.
I love the Gordon-clean, very quiet, great transient response. Most important is that I never hear it.
If you want more technical answers, Grant Carpenter is always happy to take the time to
explain.
Old 24th March 2021
  #24
Gear Head
 
🎧 5 years
Studer58, FWIW this post in another thread links to three official AEA demos of their ribbon mics using DAV BG1 pres
DAV BG-1 sound samples?
Old 3 weeks ago
  #25
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GIACOMO-_'s Avatar
 
🎧 10 years
DAV BG2: input impedance 20k ohms pad out, and 1.6Kohms pad in.
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