Taperssection.com
Gear / Technical Help => Battery Boxes, Preamps, Mixers, ADCs, and Processors => Topic started by: tailschao on March 09, 2013, 05:44:43 PM
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For the sake of my own curiosity, can someone give me a rundown of the specifications of the various CA preamps? The CA website is rather, erm... minimalist (the entry for the 9200 reads simply "preamp", lol), and it gets hard to keep all the differences in my mind.
For example, I own a 9100, and while the gain range is labelled as 0 - 20 dB, from what I understand 0 gain is actually at around 11 o clock on the knob, and everything before that is attentuation. So, does the gain actually go all the way up to 20 dB? Or, does it stop at less, because what the label says is 0 is actually some amount of attentuation?
For the preamps with stepped gain (9200?), what is the value of a stepped gain plus an output volume knob? Adding, for eg, 15 db of gain and then attentuating the output by 5 db to avoid clipping? Why? Why not just add 10 dB of gain?
The UGLY preamps... do I remember than one of them has to be adjusted with only a screwdriver? This is the UGLY I? UGLY II has a knob?
So, yeah... what is the gain range (actual gain range and 'labelled' gain range), stepped/variable, size, controls, HPF fuctions, etc, of each of the CA preamps? General specs. I don't want to bother Chris by PMing him directly, I'm sure other people can answer these simple questions, they just don't seem to all be written down anywhere.
Also, how many "versions" of these are there? I understand that there are have been changes to each preamp over the course of their existence? A 9100 that I might buy today will not be the same as the 9100 I bought back in 2007? These version changes seem rarely talked about, but I don't think I imagined them.
Thanks...
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ST-20 preamp was the first IIRC.
Sends 9V, switch for 0dB/+12dB (I assume.....Chris will have to verify this, label is worn off but originally said +30db?)...
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I think it's best to allow Chris to best explain the differences but I think all makers on here are constantly revising and improving their product. Jon at Naiant is constantly tweaking and impoving his "Box" products as well. A product you bought last year, even, might be significantly improved by this time. None of these builders want to "rest" on a product.
The 9100 allows you to attenuate and gain up levels -- as you've mentioned 11 o'clock on the 9100 is unity; that means if the 9100 is cranked all the way, you're boosting the input by +20dB and you can also reduce the "hotness" (soundboard feed, for example) before it reaches your deck if needed. I believe it's about -10dB at the lowest. HPF is selectable.
The 9200 is designed with a different approach. It gives you up to +40dB of gain in fixed steps and uses quieter electronics (less hiss than the 9100). The steps that Chris has chosen might not make sense to you but they're real-world tested and make sense once you get out there. The secondary pot allows you to fine-tune your levels if you need that "little bit more" gain. HPF is selectable.
The UGLY preamp (the original) has two pots that require a screwdriver or tweaker to adjust but you have the ability to "fix" any mics that might not be perfect matched before you record. I used the UGLY preamp as a "battery box with gain" because I had a pair of mics that were about 2.5dB apart. I also knew I needed about +12 or +14dB to get the mics into the ballpark I wanted so I'd set it and forget it. The internals are shared with those of the 9200 but the original UGLY doesn't allow you to step up other than using a tweaker. The UGLY II adds the same 6 step switch that's seen in the 9200 _PLUS_ the ability to fix mismatched mics. Neither of these have HPF switching so you'll have to do that in post.
The 9100 and 9200 are the same size box. The UGLY and UGLY II are maybe 1/3 of the height but a little thicker (think the size of 9V battery doubled up once the internal components are epoxied on the front).
Hopefully that'll help until Chris steps in.
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I am on my way out of town this morning for a day. But when I get back I will answer your post.
Chris
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The secondary pot allows you to fine-tune your levels if you need that "little bit more" gain.
..The UGLY II adds the same 6 step switch that's seen in the 9200 _PLUS_ the ability to fix mismatched mics.
I have the original UGLYs.
As I understand it, the small trim pots attenuate the gain of each channel individually, providing fine control to adjust level balance. They are the only gain controls on the original UGLY and are used to both adjust the balance between channels and adjust the overall gain applied to both channels. On the UGLYII (and possibly the 9200?) which have an additional master stepped gain control, their primary use is to balance the output level between two mics with slightly different sensitivities by reducing the output of one channel to match the other. They don't add a "little bit more" gain but do just the opposite.
There is another way to use them, and that is to reduce both pots by the same amount (in addition to what is needed to achieve channel balancing) to effectively reduce the level of each stepped gain position on the stepped master gain knob. That means the actual range of settings provided the stepped knob may be effectively adjusted to a range which is most appropriate for your rig, and could include settings which make no gain change (unity gain) or even attenuate the mic input using settings at the bottom end of the stepped gain knob range if the full 40dB of gain is not required at the top end of the range.
Chris please correct me if I'm wrong. I hope that's correct, as that is how I plan to use the new ones I plan to order!
Many people using less sensitive mics may always want a range of positive gain settings, but I want a range of ideally about -10 or -5dB to about +15 or +20dB, considering the DPA 4060 mics I use with these preamps have a relatively high sensitivity of 20 mV/Pa (or -34 dB re. 1 V/Pa) and the small recorders I use with these do not have huge amounts of headroom in their input stages.
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The 9200 is designed with a different approach. It gives you up to +40dB of gain in fixed steps and uses quieter electronics (less hiss than the 9100). The steps that Chris has chosen might not make sense to you but they're real-world tested and make sense once you get out there. The secondary pot allows you to fine-tune your levels if you need that "little bit more" gain.
I'm still not clear what the variable output control does on the 9200. Does it allow me to variably select gain from 0 to the current stepped value? What do you mean by "that little bit more gain"?
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Correct. The 9200 gives you the ability to jump to the specific gain level required and then the second pot allows you to fine tune within that parameter (if I'm not mistaken). So, if you needed +8dB, you could jump to the first step (+5dB) and then add +3dB more gain using the variable pot.
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Correct. The 9200 gives you the ability to jump to the specific gain level required and then the second pot allows you to fine tune within that parameter (if I'm not mistaken). So, if you needed +8dB, you could jump to the first step (+5dB) and then add +3dB more gain using the variable pot.
[bold and italics above are my addition]
Hmm. That's confusing.. and contradictory. Using your example, +8dB is not within the 0-5dB range.
Can we get a definitive answer on this, Chris?
Do the channel trims attenuate the overall gain from that set by the stepped large knob?
(my asumption, and as phrased in rodeen's question)
Or are they actually a second gain stage as Adrian seems to imply?
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From the ca-9200 thread: http://taperssection.com/index.php?topic=139565.0
"2- The trim control is really an output level control that is 00- to what ever the gain is set too.. The gain steps are based on what I feel is the most useful range. The remainder of the difference can always be made up with the recorders gain setting.. Again most people should shoot for -15 to -10 db tops on the VU so that there is no overloading. So in most cases going a range higher then what is needed and then backing off on the output accomplishes the same thing."
In my experience, always have the trim turned up all the way at the desired gain step and dial it down if necessary.
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Thanks! Exactly the info I was looking for.
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The trim control is really an output level control that is 00- to what ever the gain is set too.
Ding!
That means the trim pots simply attenuate the output.
In otherwords they are not controlling the gain of a seperate amplification stage and cannot increase gain above what is set by the stepped knob, only reduce it as desired. Which is how I expected and hoped it would work.
Thanks for the legwork jibooer!
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Correct. The 9200 gives you the ability to jump to the specific gain level required and then the second pot allows you to fine tune within that parameter (if I'm not mistaken). So, if you needed +8dB, you could jump to the first step (+5dB) and then add +3dB more gain using the variable pot.
My understanding is that your explanation of the variable pot is not correct. If you have the CA-9200 set at 40 db, for example, and the output at the max, you will be getting 40 dB of gain. The variable pot does not add any gain, it only provides attenuation. To get 8 dB of gain, you would need to set the CA-9200 to 10 dB and turn down the output a little bit.
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I am on my way out of town this morning for a day. But when I get back I will answer your post.
Chris
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The trim control is really an output level control that is 00- to what ever the gain is set too.
Ding!
That means the trim pots simply attenuate the output.
In otherwords they are not controlling the gain of a seperate amplification stage and cannot increase gain above what is set by the stepped knob, only reduce it as desired. Which is how I expected and hoped it would work.
Thanks for the legwork jibooer!
You are correct the level control controls the output level of the preamp and can be used in a pinch to lower levels if you are getting into the red on your recorder. It can be used to get a large amount of gain then reduce it for things like camcorder.
Chris
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For the sake of my own curiosity, can someone give me a rundown of the specifications of the various CA preamps? The CA website is rather, erm... minimalist (the entry for the 9200 reads simply "preamp", lol), and it gets hard to keep all the differences in my mind.
For example, I own a 9100, and while the gain range is labelled as 0 - 20 dB, from what I understand 0 gain is actually at around 11 o clock on the knob, and everything before that is attentuation. So, does the gain actually go all the way up to 20 dB? Or, does it stop at less, because what the label says is 0 is actually some amount of attentuation?
For the preamps with stepped gain (9200?), what is the value of a stepped gain plus an output volume knob? Adding, for eg, 15 db of gain and then attentuating the output by 5 db to avoid clipping? Why? Why not just add 10 dB of gain?
The UGLY preamps... do I remember than one of them has to be adjusted with only a screwdriver? This is the UGLY I? UGLY II has a knob?
So, yeah... what is the gain range (actual gain range and 'labelled' gain range), stepped/variable, size, controls, HPF fuctions, etc, of each of the CA preamps? General specs. I don't want to bother Chris by PMing him directly, I'm sure other people can answer these simple questions, they just don't seem to all be written down anywhere.
Also, how many "versions" of these are there? I understand that there are have been changes to each preamp over the course of their existence? A 9100 that I might buy today will not be the same as the 9100 I bought back in 2007? These version changes seem rarely talked about, but I don't think I imagined them.
Thanks...
9200 There has only ever been one version it has 40 db of gain and an output level control.
The ugly II is the same preamp as the 9200 except no high pass filter. And no output level knob only left and right trim pots and the same rotary gain control as the 9200 with the 6 different gain ranges.
The 9100 is 20 db of gain max and has a range from 00 to +20 db of gain. And the control is not calibrated per say 12 oclock is not 50% its more like 70% and most the gain comes in after that point. There are many different versions of this preamp as I tweaked it quite a bit. Now its the 4.4 and its the last version of this preamp that will be made. The major difference between the ones built in 2005 to 2009 were lower bias voltage for mics of less than 7 volts. The new 9100 puts out almost 9volts. More than enough to power our mics.
The 9000 series is being phased out.
The ugly has been phased out.
But I will build for special requests.
The new phantom powered preamp is being worked on as we speak. And will be available when its perfect and works as intended. And its almost there.
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I am on my way out of town this morning for a day. But when I get back I will answer your post.
Chris
I guess I was out of town for a long time eh? thanks for reminding me :)