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Battery Powered Preamp Single-Channel Preamps
Old 27th January 2017
  #91
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The nominal impedance of the ISLETA is 3k Ohms, but Scott can customize that for you. I am planning to special order mine with a 3k/13k impedance switch.

Quote:
Originally Posted by brhoward View Post
Since Scott hasn't mentioned the input impedance yet I thought I'd remark that as we can see from the specs the unit has less input noise (EIN) and the same amount of gain as the AEA RPQ (made for ribbons). But, from what I have read here and elsewhere, that input impedance is also a very important factor.

However, from my experience noise problems with ribbons hasn't been the preamp, but RF and magnetic induction issues in spaces and places—not to mention dirty power.

I bet the ISLETA will work great, especially since it is floating from **** location power.
Old 28th January 2017
  #92
I didn't see if it was battery only or if you planned on adding a DC input as well. Just curious.
Old 28th January 2017
  #93
Gear Addict
Hi Daniel,

From Post #81 :

Quote:
Originally Posted by PuebloAudio View Post
...Unfortunately, such systems are not capable of suppling ISLETA's required native power voltages. Further, central powering would defeat the benefits of ISLETA's completely floating operation. Providing an external powering option would increase costs several $100 while decreasing sound quality. That's a lose-lose in my book. Understandably, there are no plans too offer external powering.
Old 28th January 2017
  #94
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Quote:
Originally Posted by bwanajim View Post
The nominal impedance of the ISLETA is 3k Ohms, but Scott can customize that for you. I am planning to special order mine with a 3k/13k impedance switch.
Thanks for helping spread the word, bwanajim! I think it might be illuminating for readers here if I share, from our emails, the reasoning behind Pueblo's chosen input impedance...

Quote:
...The subject of input impedance is a little more complicated because there is no single, best solution. No single Zin value is perfect for every mic. As an example, AEA takes the position that transformer coupled ribbons are best loaded with very high Zin: 10kΩ to 33kΩ. They explain that this buoy's the mic's low frequency resonance (say 50Hz) thus preventing bass dip. I can go along with that. However, there are repercussions for that very hi Zin which under-damps the mic transformer and manifests impulse response distortion. To my ears, this sounds more objectionable than the low freq dip. Consider that a mic's designed voicing is most likely derived using a nominal Zin of 1.5k; not, say, 30k. I would add that higher Zin can inflate exposure to EMI/EMF. It casts a wider net for capturing possible noise radiation and interference.

Engineering analysis along with years of empirical recording under professional conditions, led me to a compromise Zin of 3k. This is a little higher than normal but not so high as to veer into punitive behavior. My position is that if you want to get the intended, designed sound of the mic, along with the most natural sonic rendering, I recommend you go with Pueblo nominal Zin of 3k, which I feel is perfect for Ribbons and just about anything else. However, if you find the effect of underdamped transformers to be beneficial in your work then ISLETA can be ordered with Zin = 13k.
Actually, I have been wondering if a Zin selector switch which toggles between 3k and 13k would be desirable as a standard feature. Please feel free to chime in with any thoughts

Last edited by PuebloAudio; 1st February 2017 at 04:09 AM..
Old 28th January 2017
  #95
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Quote:
Originally Posted by brhoward View Post
...from my experience noise problems with ribbons hasn't been the preamp, but RF and magnetic induction issues in spaces and places—not to mention dirty power.

I bet the ISLETA will work great, especially since it is floating from **** location power.
HERE, HERE!! I could not agree more.

Yes, EIN is one indicator of how noisy a preamp might be. But in today's omni-wireless world and polluted mains power service, CMR (common mode rejection) is just as important. CMR indicates how well the preamp can keep EMI/EMF pollution out of the signal path; thus excluding additional noise + distortion.

Browsing through some spec sheets of other manufactures (SD or Hapi, for example) reveals CMRs of only 60dB at 10kHz. Compare that to Pueblo's CMR of 100dB and it's plain to see they are not even in the same galaxy. Pueblo being 100 times better!

Perceived total noise depends on more than just good EIN figures (which Pueblo can also claim). Please consider giving CMR the same attention that EIN typically receives. Understanding both will paint a more complete picture of a product's noise potential.

Last edited by PuebloAudio; 29th January 2017 at 06:32 PM..
Old 29th January 2017
  #96
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Quote:
Originally Posted by PuebloAudio View Post
Thanks for helping spread the word, bwanajim! I think it might be illuminating for readers here if I share, from our emails, the reasoning behind Pueblo's chosen input impedance...



Actually, I have been wondering if a Zin selector switch which toggles between 3k and 13k would be desirable as a standard feature. Please feel free to chime in with any thoughts
On the benchmarkmedia pre420 the input impedance switches between 1.3k and 8k.
Grace m802 has 4.2k input impedance, regardless of ribbon mode.

Royer labs write in their sf12 manual that 1.5 K is sufficient.
Samar audio also expect a standard modern impedance, not a special ribbon input.

just some thoughts...

Is there any way to test this preamp in Belgium ?
Old 29th January 2017
  #97
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Quote:
Originally Posted by Yannick View Post
...
Is there any way to test this preamp in Belgium ?
Arnd at Digital Audio Service, Germany, would be the closest dealer to you. They already carry the Pueblo JR series preamps. Arrangements have yet to be made for ISLETA since it is still in development, but I expect that may become an avenue for you.
Old 31st January 2017
  #98
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Scott,
As the guy who wants to order an ISLETA with a 3kΩ/13kΩ impedance switch, you can guess that I'm all for this idea! Because this preamp is so quiet and has so much gain, it's seems naturally destined for use with passive ribbons. The fact that it is self-powered, allowing it to be placed very close to the mic without regard for power availability makes it even more suitable for that application. As an aside, the Grace m103 ribbon mode switches the unit from it's nominal 8.1kΩ to 20kΩ.

In my opinion, a high value add for the ISLETA. I am looking forward to using mine with my SF12 and R88.

Quote:
Originally Posted by PuebloAudio View Post
Actually, I have been wondering if a Zin selector switch which toggles between 3k and 13k would be desirable as a standard feature. Please feel free to chime in with any thoughts
Old 31st January 2017
  #99
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I too would be interested in the impedance switch. I will pay for it as a custom mod or take it standard on the ISLETA.
Old 31st January 2017
  #100
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Quote:
Originally Posted by PuebloAudio View Post
Actually, I have been wondering if a Zin selector switch which toggles between 3k and 13k would be desirable as a standard feature. Please feel free to chime in with any thoughts
Yes, please!!! I would love this!

-Mike
Old 31st January 2017
  #101
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Quote:
Originally Posted by PuebloAudio View Post
Actually, I have been wondering if a Zin selector switch which toggles between 3k and 13k would be desirable as a standard feature. Please feel free to chime in with any thoughts
Changing preamps because of their particular input impedance is one of the things I find myself doing often. Having an option to adapt this by means of a switch would be highly desirable. Whether the mentioned values are best chosen is something I am not sure about. Both seem a tad high to me. 1.5k Ohm and 10k Ohm seem more approriate, based on my most preferred values for condensers and ribbons.
Old 31st January 2017
  #102
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I am looking for a portable battery 2ch pre-amp myself as an addition for my Nagra VI and discovered sofar mic preamps from Kortwich (Germany) and Rens Heijnis (Netherlands). Would like to know what price range the Pueblo will be.

Here a link to Kortwich

VCP preamp: Filmtontechnik

Here a link to Rens Heijnis

Rens Heijnis custom-built audio equipment

Another question is why choose one over the other??


Gaston Matthijsse
Old 31st January 2017
  #103
has anyone got experience with powering their 220V machines with battery power? Can you get "cleaner" power, and thus get better sonic specs, from a car battery, that outputs 220V via an inverter, than just using regular gridpower ?
Old 31st January 2017
  #104
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just.sounds's Avatar
Sonosax has some offerings.
Old 31st January 2017
  #105
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Quote:
Originally Posted by monitor View Post
has anyone got experience with powering their 220V machines with battery power? Can you get "cleaner" power, and thus get better sonic specs, from a car battery, that outputs 220V via an inverter, than just using regular gridpower ?
Yes and no, good regultators spec better than batteries but batteries are constant so with some gear it improves and some gear will stay the same. But the inverter has to be very good. And your ground also!!
Old 31st January 2017
  #106
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Why not even higher input impedance?
The higher the input impedance the less
damping of a ribbon mic and the better
low frequency response?
The AEA TRP mic preamp has an input
impedance of 33k. The Gordon preamp
has an input impedance of 2 megaohm
to completely unload the microphone.
While the Gordon does have a button to
switch to a 1k input impedance Grant says his customers almost never use this
setting.
Bill
Old 1st February 2017
  #107
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Quote:
Originally Posted by Earcatcher View Post
Changing preamps because of their particular input impedance is one of the things I find myself doing often. Having an option to adapt this by means of a switch would be highly desirable. Whether the mentioned values are best chosen is something I am not sure about. Both seem a tad high to me. 1.5k Ohm and 10k Ohm seem more approriate, based on my most preferred values for condensers and ribbons.
Thanks for your input, earcatcher.

No matter which values I ultimately choose for the stock Zin's, there is still opportunity to order custom values. They will just need to be under 13.6k. So your 1.5k & 10k values are possible upon request.

Last edited by PuebloAudio; 1st February 2017 at 03:51 AM..
Old 1st February 2017
  #108
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Quote:
Originally Posted by Folkie View Post
Why not even higher input impedance?...
Hi Folkie,

Reasons offered earlier in post 94.
Old 22nd May 2017
  #109
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Quote:
Originally Posted by PuebloAudio View Post
Hi David,

Most of my energies are presently being directed at the release of the OLLA Hybrid DI box. That product is on track for 1st Quarter 2017 release. Man, oh man am I pumped about that little champion!

ISLETA will follow as quickly behind OLLA as possible. I am striving for 2nd Quarter.
Hello Scott,

Do you have an updated timeline on the release of the ISLETA?

thank you,

David
Old 24th May 2017
  #110
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Quote:
Originally Posted by dactylus View Post
Hello Scott,
Do you have an updated timeline on the release of the ISLETA?

thank you,

David
Hi David & All,

Apologies for delayed updates. This band from Ireland has been monopolizing my attention for the last few months with 30th anniversary projects and such.

Because of the above I have not only neglected ISLETA news, but also overlooked announcing on GS that our new OLLA Hybrid DI Box was released last month! I am very pleased with how it turned out (pic attached). Great versatility, faultless sound quality, and sweet looking stainless-steal construction. Gratified to be receiving happy, positive feedback. In its first month, over half the first production run has already been sold off.

Back on topic, the ISLETA circuit board is designed and parts have been purchased and stocked. Completing a great chassis design is the last challenge. At this time I have aim on late 3rd quarter.

Thanks for your continued interest and patience,
Attached Thumbnails
Battery Powered Preamp-img_1201.jpg  

Last edited by PuebloAudio; 24th May 2017 at 09:18 PM..
Old 25th May 2017
  #111
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Plush's Avatar
Strong move and worth waiting for I know.

I like the form factor of your new DI.
Old 25th May 2017
  #112
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Thanks for the update, Scott. Looking forward to it.
Old 25th May 2017
  #113
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The DI is just plain awesome. Bought a pair and posted this review on another site:

So I just got a pair of the new Pueblo Audio DI boxes and I have to talk about how wonderful they are. They are by far the best sounding DIs I have ever used. I'm still sort of working them out as the summer concert (band) season gets going, but these are my impressions. I used the prototypes on guitar a few months back and was very impressed. Shot it out versus the KT DN100, which is a good basic DI. Destroyed it. Bigger sound, more open and more smooth. And this wasn't the final design.

It's an odd design in that there are actually 3-4 DIs in one box. There is an active stage (with a choice of 2 impedances), a passive DI and a DI for use between an amp head and speaker. Just turn the switch to choose which one you want. Top impedance is a whopping 45Mohm. The transformer inside is a custom job that Jensen did for Pueblo and is unlike anything else on the market.

The new ones are in a rolled steel box. Recessed screws make it a solid construction to withstand the rigors of stage use. It has a very clean sound. I have now used it on a couple bases and a violin. In the past, I would gravitate towards "color" boxes for bass. Make it sound big and thick. This is not that kind of box. Instead, the bass through this ended up clean, smooth and had a solid bottom end. The mushy feel in the hall where I was mixing completely disappeared. Didn't need to rely on a lot of compression and EQ to make it work (which was nice for a change). Just sat in the mix as needed. As for the violin, that is where I was blown away. Multiple times I found myself working by habit. Normally I push the sound until I hear the nasty pickup sound and then I pull it back a little. Multiple times, I found myself realizing that the violin was a bit over-balanced because I pushed it too far as I didn't hear that traditional DI sound. It was smooth and rich. Last thing I would have expected (and I knew the player and her setup).

A DI, especially a non-tube one doesn't really sound like it should be sexy, but this is one sexy beast. It isn't inexpensive, but it's worth it in that it satisfies multiple situations as well as the build quality.
Old 27th May 2017
  #114
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Quote:
Originally Posted by PuebloAudio View Post
Hi David & All,

Apologies for delayed updates. This band from Ireland has been monopolizing my attention for the last few months with 30th anniversary projects and such.

Back on topic, the ISLETA circuit board is designed and parts have been purchased and stocked. Completing a great chassis design is the last challenge. At this time I have aim on late 3rd quarter.

Thanks for your continued interest and patience
Thanks for the update Scott!
Old 2nd October 2017
  #115
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Hello Scott,

Do you have an updated timeline on the release of the ISLETA?

thank you,

David
Old 1st November 2017
  #116
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Yannick's Avatar
 

Bump ?
Old 2nd November 2017
  #117
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brhoward's Avatar
 

Quote:
Originally Posted by Yannick View Post
Bump ?
Scott sent this email a few weeks back:
"Dear Isleta Followers,

The effort continues to perfect the chassis for Isleta. It is proving to be a challenge to design and fabricate a chassis that is strong, lite weight, ergonomic *AND* affordable. Add to that an unexpected, yet welcome upturn, in orders for our existing products plus my intimate involvement with a little band from Ireland's upcoming world-wide release, and well... its just taking longer than I would have expected to complete this product.

But continue it does. Investments in R&D, parts stock, etc. are well into tens of thousands so we are committed. Have no fear, ISLETA will be born! I am very excited for this product. Though I say it myself, I do believe this will be a game changer. I do not know any product that will deliver the feature and extreme audio quality will being completely off the grid for days on end. Attached is a rough drawing of the side view showing the main outputs and 1/8" stereo aux out. Also a picture of the prototype in a production sound bag, on location for a documentary shoot.

Good things to come for sure."
Old 2nd November 2017
  #118
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I was hoping to buy one before december.
If the preamp is as good as I hope, in the future I need at least two stereo versions and four mono versions.

Question: are the mono versions definately scrapped, or will they happen in the next year or so ?

My go to main array consists of three microphones ...
Old 2nd November 2017
  #119
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Quote:
Originally Posted by PuebloAudio View Post
The price is not yet fixed as we are still finishing the vetting process for various options. A rough estimate would be somewhere between $450-$750 depending on the features.

The $650-750 price area includes a precision 24pos switch, 2.5dB per step as in the standard Pueblo range. There are two outputs: one transformerless, quasi-balanced output and one transformer-balanced output. These can be used at the same time. This offers two sonic flavors and accommodates backup recorders, monitor feeds, etc. A stripped down version, without the transformer output, might land in the $450-550 area.

Those prices do not included the two rechargeable batteries which are $39 each. A battery recharger would also be required and not included in the above pricing.

Those are the projections for now. They will come more into focus as the design tightens up and desired quantities become known.
Any idea if the extra work on the chassis is likely to nudge up these rough estimates on pricing?

I am looking forward to compare the Isleta to a Nagra EMP I have, or hearing from someone who has done the same.
Old 3rd November 2017
  #120
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Quote:
Originally Posted by Yannick View Post
I was hoping to buy one before december.
If the preamp is as good as I hope, in the future I need at least two stereo versions and four mono versions.

Question: are the mono versions definately scrapped, or will they happen in the next year or so ?

My go to main array consists of three microphones ...
Hi Yannick,

Sorry I haven't been very active on Internet forums these past months. Business has been at maximum throttle, which is a blessing but can cause unintended neglect in other areas. Since I don't know how active I will be on GS these next few months, I encourage folks to join the newsletter found on this web page...

http://puebloaudio.com/isleta---battery-preamp.html

Though I felt a mono version was a more logical format, the expressed desire for a stereo version was overwhelming. It is beyond the man-hours and financial commitment of a little company like Pueblo to launch both a stereo and mono version, simultaneously. At present there are no plans for a mono version. That being said, if a serious enough demand arises for a mono version then it could happen. There just needs to be at least 25 units worth of market out there to be worthwhile.
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