Active mic splits as mic preamps

[recordinghopkins]

What are your thoughts about using an active splitter as both a split and a mic pre, for connection directly to a pair of HD24xr's? Something like the Klark Teknik Square One active splitter. This would be used for anything from Jazz to el-screamo.

If you'd like some more info:
My current rig is 24 channels, and I have been using ART S8 passive splits, with ART Tubefire preamps into an HD24xr, and then on to DAW via ADAT outputs.
I have been taking the direct split and giving venues the S8 transformers for years with not one complaint. I mostly work small-ish venues with house FOH engineers that don't care one way or the other about getting the transformer split, as long as they get phantom where they need it.

SIMPLIFIED, the signal flow would be this:


Mics > S8 passive Splitter
> transformer split available here > (monitor, broadcast, or FOH)
S8 direct out > Klark Teknik Square One (phantom provided here)
> Active Split 1 > HD24xr #1
> Active Split 2 > HD24xr #2
> transformer split available here > (monitor, broadcast, or FOH)

OR

Mics > S8 passive Splitter
> transformer split available here > (monitor or broadcast)
S8 direct out > Klark Teknik Square One (phantom provided here)
> Active Split 1 > mult to HD24xr #1 and #2, or daisy chain 24xr's
> Active Split 2 > FOH
> transformer split available here > (monitor or broadcast)


This looks like it could be an incredible value if I can knock out the upgrades of my split and amps at the same time. I do like the idea of active splits to reduce the length of cabling powered by the mics' output.
Of course, reliability is something of a concern over passive splits, especially when the whole show is riding on them to stay powered and working. I could always continue to give the house the passive ART transformer split, then if the active splits go down, it won't matter. UPS is assumed.


Thanks,
Greg

[audibell]

Hey G
My first concern would be the bandwidth of what are line amps, into recording pres. If, as you suggest, the outputs go straight into the HD24s and the quality is acceptable, then the Shanghai purple beasties will economise.

The chance to use meaty or clear pres is limited by how much the active splitters' line amps alter the signal in an unhelpful way before entering recording preamps. SteveR uses KT active splitters, perhaps he already knows whether this is a valid concern.

For violin and soprano soloes I feel better using the hv3 type pres and my mics - if foh wants a mult, I'll give them a line level output off the dual outputs, rarely a passive iso because it reduces the remaining mic-level signal. I know you do rock stuff so maybe you're good to go with this.

I wouldn't option daisy-chaining one HD24 into another - I don't have two to try it but I don't think signal is passed-thru to the outputs in the event of a power interrupt in the first unit - JimWilliams will know if this is so. My older KTs 360/410 do pass signal with power off so perhaps the square jobbies do too.

FullCompass seems to have the best prices for these.
You're getting your money's worth out of those Arts :>
rgds
WalterT

[recordinghopkins]

Forget all of that. My real question is: Even if I don't need a split, will it serve me as a quality 8 channel mic pre? Is 40dB of gain enough? Let's start there. If not, the rest is moot.



Thanks for the reply.
My biggest concern is the usability of the preamps on their own. I need versatility. I really want someone to tell me that the Midas-inspired preamps really are on par with expectations, as advertised. Acceptable quality is the question, as you suggest.

Tech specs indicate that it will output as hot at +22dbu, so there should be no problem with signal strength straight into an XR.

The KT's will also handle line level inputs, so any preamps I would want to use for coloration should play well on the front end, pre-split. I don't often use specialized preamps for particular inputs, unless it's a jazz gig, because my setup time is usually limited to the 6pm load in for an 8:30 or 9:00 show - just like the band. I have to be up and running before the artists so soundcheck can be done in a timely manner. Simplifying my rig has been an ongoing project to shorten my setup and strike time. If I have access a couple hours earlier for larger events, I will bring in some special pieces, but on the whole, I've got my routine down to about 45 minutes from arrival to sound check without an assistant.

Because I often record more than one act in an evening, input order and type sometimes changes between sets, so that special preamp I used for female vocals with the last group might now be on a saxophone or a conga drum. Never mind the changes in genre that are encountered. Re-patching is out of the question when set change happens in only 10 minutes, and I'm often forced to set levels on the fly. Luckily, I know the safe operating range for my current rig, and I can usually get it pretty darn close before the first downbeat. I always get a sound check with the group or artist that hired me, but the add on clients that I get once I'm on location can make a complicated rig even more so. Especially since I am usually a one man operation.

Indeed, Full Compass is as cheap as I've seen other places. Good lookin' out! They're on the bay right now for the same price from Pro Audio Star in Brooklyn.

[MichaelPatrick]

40dB is not enough gain for dynamic mics - not enough to drive an AD converter. If your ADC has an adjustable line amp with +20dB gain then it's enough.

Signal quality remains a question but Midas preamps are surely as good or better than Mackie, Soundcraft, AH, etc...

[Jim Williams]

I avoid active splits of mic signals. My preamps are far less noise, why degrade that? Any active splitter will add noise, THD and reduce bandwidth. Splitting AFTER the mic preamp can be done.

Jensen splitter transformers avoid those problems.

[recordinghopkins]

Thanks Michael and Jim,
I think I have given in to the fact that my upgrade budget is best spent on new dedicated preamps. As long as I continue to only need to take the transformers occasionally, I'm happy.

[MichaelPatrick]

Originally Posted by recordinghopkins

Thanks Michael and Jim,
I think I have given in to the fact that my upgrade budget is best spent on new dedicated preamps. As long as I continue to only need to take the transformers occasionally, I'm happy.

Greg, I don't do full multichannel splits (FOH, FB, BCAST) but I do have an occasional need for several clean splits. For that I use Radial JS-3 boxes. With top quality Jensen XFMRs and excellent build quality I never worry when using them.

[recordinghopkins]

That's great to know.
Do you take the transformer?
What are the benefits or problems with recording the iso split, other than phantom management? Are there instances where high quality iron in your signal path by choice may be desirable for sonic reasons, versus taking the direct? I would never choose to use the transformers in the ART S8 splits that I have, but I make do with them when I have to. If I upgrade, will I find myself choosing the transformer split on purpose? Obviously we're not talking about classical or purist jazz here, where preservation is the name of the game (Jim, I know how clean you like your signal path!). Could this type of transformer be used in the studio for coloration and creative purposes, say between an outboard compressor and the console insert return?

[recordinghopkins]

Actually I suppose you wouldn't want to use mic split transformers with line level. That's what line level transformers are for, no?

[MichaelPatrick]

Originally Posted by recordinghopkins

That's great to know.
Do you take the transformer?
What are the benefits or problems with recording the iso split, other than phantom management? Are there instances where high quality iron in your signal path by choice may be desirable for sonic reasons, versus taking the direct? I would never choose to use the transformers in the ART S8 splits that I have, but I make do with them when I have to. If I upgrade, will I find myself choosing the transformer split on purpose? Obviously we're not talking about classical or purist jazz here, where preservation is the name of the game (Jim, I know how clean you like your signal path!). Could this type of transformer be used in the studio for coloration and creative purposes, say between an outboard compressor and the console insert return?

Radial's JS-3 is a 3-way splitter with one direct out and two Iso outs. In my applications the FOH is not often picky - I can send them an Iso feed and they're happy, so I take the direct.

Other times, when I want to capture an identical signal on two preamps or converters, I'll use both Iso outputs. The quality is good enough that I'll trust it for all but the most critical recordings.

[MichaelPatrick]

Originally Posted by recordinghopkins

Actually I suppose you wouldn't want to use mic split transformers with line level. That's what line level transformers are for, no?

Right. For line isolation I use a Radial Twin-Iso box. I don't often split line level. When I do a small mixer does the job.

[recordinghopkins]

I see.
New splits are definitely on the menu, although a low priority. I think the first course of upgrades this year is going to be mic preamps.
Actually, I'm thinking of ditching the preamp rack altogether and getting a studiolive 24, and using the direct outs to the HD24 for backup. As far as mic pres go, the studiolive is surely more neutral and flexible than my current mic amps. Bonus: my live to 2mix gigs will no longer require renting a mixer, and it will make monitoring so much easier than ITB.

[Jim Williams]

I do it similar, a HD24XR with a 16 channel Soundcraft Delta. The inserts are the send/returns to the HD24 along with an 8 channel outboard preamp for the last 8 tracks. That way I can send to auxes, use the main outs and faders as a house or video feed and monitor every thing as I use the extra 8 returns to monitor channels 17~24. It's small, light and portible. The modified Delta mic preamps are first rate in clarity.

[recordinghopkins]

I just blew my upgrade cash on a studiolive 24, a roadcase, and parts to make three db25 cables. First impression... awesome! I'll be putting it to work with these guys on the 6th, if I can get cabling taken care of by then.

[MichaelPatrick]

Originally Posted by recordinghopkins

I just blew my upgrade cash on a studiolive 24, a roadcase, and parts to make three db25 cables. First impression... awesome! I'll be putting it to work with these guys on the 6th, if I can get cabling taken care of by then.

Congrats!

Harry Butler (hbphotoav) went that route and he's very happy he did. I hope you'll soon be sharing some clips and experiences with us.

[recordinghopkins]

Originally Posted by MichaelPatrick

Congrats!

Harry Butler (hbphotoav) went that route and he's very happy he did. I hope you'll soon be sharing some clips and experiences with us.

Thanks!
I made my purchase based in part by some of Harry's comments about the studiolive and it's practical uses. I am amazed by how many features and routing options they packed into this thing.

I'll continue to use the splits I have, and take direct as often as possible. I plan to do a null test on them this weekend, just for kicks. I've never had a house engineer tell me that his mixes sound any different, only, of course, that they need to add a bit more gain.

There is a chance that this mixer will replace my giant soundcraft for mixing duties. My only real problem with it is that I can't use outbboard gear with the firwire return. To solve this problem, I may just run it as a stand alone mixer and use the direct outs and line inputs to connect to the HD24xr and Presonus lightpipe, as the Sapphyre is now. I'll make an insert and aux patchbay, and it's ready for studio duty. We'll see.

[Remoteness]

I'm coming in a bit late, but for what it's worth, check this out...

As many of you already know, I have hundreds of channels of passive and active splitters in all sorts of sizes and configurations.

...and, I pick which system we end up using depending on the situation at hand.

I prefer the direct output, but don't mind the transformer out if FOH must get the direct because I know the build quality and exactly how our splitters sound.

It's very rare to hear a house or monitor engineer tell me that their mixes sound different going through our splitters.

On the active splitter front, we only use XTA and BSS splitters.
We don't have any KT active splitters in our shop.

We also have all sorts of preamps to choice from, but that didn't stop me from modifying a few of our XTA DS800 active splitters to do double duty on our "budget" rigs. (more on that later)

Yes, I know that some folks avoid active splitters, but I have found good and valuable uses for them.

We have over 160 channels of XTA DS800s in various sizes and channel counts.

These are active mic/line distribution amplifiers that also act as splitters.
You don't need any XLR/TRS adaptors and they play nice with all FOH console preamplifiers.

The input of the DS800 has a mic and line switch.
When it's switched to line the input is padded by 20dB and the input impedance changes to >10k Ohms.

The input gain switch sets the channel gain to +10dB, +20dB, +30dB, +40dB or +50dB. You also have a -10dB pad when the DS800 detects 48 volt phantom power on the monitor output XLR.

Just to be crystal clear about this matter; we use these units a lot and have fed OB units, FOH & MON consoles and such with no problems whatsoever.

We modified some of our DS800s by removing those resistive network switches and replaced them with single turn 10k pots for our "Budget 24" rack.

The "Budget 24" rack has three modified DS800s; two HD24XRs; one M480 line mixer plus a patch bay, a bunch of ELCO90s all in one 20U spaced rack.

It's used on many of our budget sessions.
The system works and sounds pretty good.
I'm happy with the results we get with that rig.

Here's a link to a thread that discusses the buildout and wiring of our "Budget 24" rack...

What does the back of your rack look like when you're wiring it?

I trust this has helped; let me know if you have any additional questions or thoughts.

[recordinghopkins]

Thanks steve,
That thread is what gave me the idea in the first place, I had just forgotten about it!

This confirms for me that active splitters can be used as preamps, although the DS800 provides 10db more gain than the KT Square One.

Ultimately, I have devised a different configuration for my kit, but thanks for the input! Active splitters may indeed be a good solution for me down the road.

[Remoteness]

Cool!

Not all active splitters have the same build quality.
IMHO, BSS and XTA are on a different level than let us say, the KT Square One and such.

I believe the key to making the DS800 work as a preamp was doing that potentiometer modification which I had XTA sign off on before we make it so.

The felt that the 10 dB steps were just too much of a difference to use as a preamp gain.

I purchased the PCBs minus the switches from XTA directly and stuffed them in my shop.

FYI, I have enough PCBs to build 16 DS800s if I like.
We have six DS800s modified to date.

Originally Posted by recordinghopkins

Thanks steve,
That thread is what gave me the idea in the first place, I had just forgotten about it!

This confirms for me that active splitters can be used as preamps, although the DS800 provides 10db more gain than the KT Square One.

Ultimately, I have devised a different configuration for my kit, but thanks for the input! Active splitters may indeed be a good solution for me down the road.

[Dave C]

I have used the XTA DS800 as a recording preamp very successfully before.

The 10dB gain steps are quite coarse, but lots of the music I record is very dynamic (acoustic jazz) and there's not a huge difference in 10dB steps versus, say, 6dB gain steps as found on some preamps.

The XTA's have good noise figures, which depending on your gain structure, can result in lots of headroom, regardless of overall gain settings. Recording at 24bit has made these issues less of a problem in general, provided the S:N of the signal being recorded is acceptable coming out of the preamp.

[Remoteness]

Agreed; we've used the DS800s before the modification with decent results.
I just like dialing in exactly what I need - 10 dB steps is to much of a leap for me, especially when you only need another 1 or 2 dB of gain.

In any event, the DS800s work smashingly well in our Budget 24 rig!

Originally Posted by Dave C

I have used the XTA DS800 as a recording preamp very successfully before.

The 10dB gain steps are quite coarse, but lots of the music I record is very dynamic (acoustic jazz) and there's not a huge difference in 10dB steps versus, say, 6dB gain steps as found on some preamps.

The XTA's have good noise figures, which depending on your gain structure, can result in lots of headroom, regardless of overall gain settings. Recording at 24bit has made these issues less of a problem in general, provided the S:N of the signal being recorded is acceptable coming out of the preamp.

[Mike H]

Originally Posted by Remoteness

We have over 160 channels of XTA DS800s in various sizes and channel counts.

These are active mic/line distribution amplifiers that also act as splitters.
You don't need any XLR/TRS adaptors and they play nice with all FOH console preamplifiers.


Just to be crystal clear about this matter; we use these units a lot and have fed OB units, FOH & MON consoles and such with no problems whatsoever.

I am trying to understand exactly how this works, since I am considering using DS800 units as preamps to an HD24XR.

If you are using the DS800's as preamps, the signals that split to the board will have been amplified, since I assume you amplify the mic Outs so the signals going to your recorder are (1) relatively balanced and (2) are a good healthy level (but not clipping).

Do the signals that are split to the board still go into the board preamps, even though they have already been amplified up to "line level" by the DS800's? If so, then the board guy just pulls back the board pres to zero level gain?

[Remoteness]

The only thing we modified on the XTA DS800 active splitters were those resistive network switches by replacing them with single turn 10k pots!

The XTA DS800s still do exactly what they were intended to do in the first place; I just wanted to be able to dial in exactly what I needed because the - 10 dB steps are to much of a leap when you only want to another 1 or 2 dB of gain.

FYI, the input of the DS800 has a mic and line switch.
When it's switched to line the input is padded by 20dB and the input impedance changes to >10k Ohms.

I suggest you check out XTA's specs directly to understand what it does...
XTA Electronics

In any event, the input gain switch sets the channel gain to +10dB, +20dB, +30dB, +40dB or +50dB. You also have a -10dB pad when the DS800 detects 48 volt phantom power on the monitor output XLR.

Just to be crystal clear about this matter; we use these units a lot and have fed OB units, FOH & MON consoles and such with no problems whatsoever. I wanted to have a single turn 10k pot instead of the 10 dB stepped switches and that is exactly what we accomplished. Everything else about the unit is intact.

I hope this helped;-)

Originally Posted by Mike H

I am trying to understand exactly how this works, since I am considering using DS800 units as preamps to an HD24XR.

If you are using the DS800's as preamps, the signals that split to the board will have been amplified, since I assume you amplify the mic Outs so the signals going to your recorder are (1) relatively balanced and (2) are a good healthy level (but not clipping).

Do the signals that are split to the board still go into the board preamps, even though they have already been amplified up to "line level" by the DS800's? If so, then the board guy just pulls back the board pres to zero level gain?

[Mike H]

Originally Posted by Remoteness

The only thing we modified on the XTA DS800 active splitters were those resistive network switches by replacing them with single turn 10k pots!

The XTA DS800s still do exactly what they were intended to do in the first place; I just wanted to be able to dial in exactly what I needed because the - 10 dB steps are to much of a leap when you only want to another 1 or 2 dB of gain.

FYI, the input of the DS800 has a mic and line switch.
When it's switched to line the input is padded by 20dB and the input impedance changes to >10k Ohms.

I suggest you check out XTA's specs directly to understand what it does...
XTA Electronics

In any event, the input gain switch sets the channel gain to +10dB, +20dB, +30dB, +40dB or +50dB. You also have a -10dB pad when the DS800 detects 48 volt phantom power on the monitor output XLR.

Just to be crystal clear about this matter; we use these units a lot and have fed OB units, FOH & MON consoles and such with no problems whatsoever. I wanted to have a single turn 10k pot instead of the 10 dB stepped switches and that is exactly what we accomplished. Everything else about the unit is intact.

I hope this helped;-)

I understand all that from your other thread, that wasn't my question.
My question is about how it affects the board, regardless of whether it has your mods or uses the 10dB increments:

"If you are using the DS800's as preamps, the signals that split to the board will have been amplified, since I assume you amplify the mic Outs so the signals going to your recorder are (1) relatively balanced and (2) are a good healthy level (but not clipping).

Do the signals that are split to the board still go into the board preamps, even though they have already been amplified up to "line level" by the DS800's? If so, then the board guy just pulls back the board pres to zero level gain?"


When you use the splitters as preamps for the recorder, the board guy will have hotter signals coming into the board......unless I'm missing something.

I just want to make sure I understand how the board guy is going to be affected, if I use the DS800's as pres. I'd like to know in advance if he is going to be unhappy.

[Remoteness]

Mike, this device was designed to interface with live sound reinforcement desks & outside broadcast consoles; this active splitter does exactly what it's supposed to do.

Again, we have used these units a lot and have fed OB units, FOH & MON consoles and such with no problems whatsoever. If the signal is too hot to the FOH or MON desk, we either bring down the gain a bit or add a pad.

Go to the XTA website and read their overview and architects' specifications.
They explain it a lot better than I can here...
XTA Electronics

Consider downloading the manual that's available on the link I provided; the manual introduction explains a lot!

Originally Posted by Mike H

I understand all that from your other thread, that wasn't my question.
My question is about how it affects the board, regardless of whether it has your mods or uses the 10dB increments:

"If you are using the DS800's as preamps, the signals that split to the board will have been amplified, since I assume you amplify the mic Outs so the signals going to your recorder are (1) relatively balanced and (2) are a good healthy level (but not clipping).

Do the signals that are split to the board still go into the board preamps, even though they have already been amplified up to "line level" by the DS800's? If so, then the board guy just pulls back the board pres to zero level gain?"


When you use the splitters as preamps for the recorder, the board guy will have hotter signals coming into the board......unless I'm missing something.

I just want to make sure I understand how the board guy is going to be affected, if I use the DS800's as pres. I'd like to know in advance if he is going to be unhappy.

[Mike H]

Originally Posted by Remoteness

Mike, this device was designed to interface with live sound reinforcement desks & outside broadcast consoles; this active splitter does exactly what it's supposed to do.

Again, we have used these units a lot and have fed OB units, FOH & MON consoles and such with no problems whatsoever. If the signal is too hot to the FOH or MON desk, we either bring down the gain a bit or add a pad.

Go to the XTA website and read their overview and architects' specifications.
They explain it a lot better than I can here...
XTA Electronics

Consider downloading the manual that's available on the link I provided; the manual introduction explains a lot!

I'm not questioning the quality of the XTA unit, they look very solid and I intend to buy one or two. I have read the manual and communicated with Waring Hayes about the units.

Again, I'm just trying to understand what would be changed at the board if I use the DS800 as a preamp.
Normally:
- You'd have a separate preamp for the recorder
- You wouldn't add much gain with the DS800, and
- the splits to the board would go into preamps in the board for amplification.

However, if I use the DS800 as a preamp, the signals to the board will be amplified to "line level" before they go to the board. This is true because the splitting in the DS800 occurs after the amplifiers.

So, it would seem unnecessary for the signals to again go through preamps in the board. Instead, you'd think they would best go into Line In connectors. I am just asking if this is what you work out with the board guy when you use your DS800's as preamps.

Maybe I'm confusing things, and my question isn't clear. Not a big deal, we'll work with the board guy and work it out.

Anyway, the DS800 units look solid, I have gotten very detailed answers to my questions from Waring Hayes at XTA, and I'll be buying one or two of these units. I believe I'll be able to use them as preamps and save the cost of separate preamps.

[MichaelPatrick]

Mike, hope you don't mind me jumping in.

You are right, the board preamps are NOT needed. Some boards have dedicated line level inputs that bypass the mic amp and others run everything thru the mic preamp circuit --even line level signals-- and you just trim them down when the input is line level.

That shouldn't matter though. If you use the mixer's line level inputs as designed you should be fine.

[Mike H]

Originally Posted by MichaelPatrick

Mike, hope you don't mind me jumping in.

You are right, the board preamps are NOT needed. Some boards have dedicated line level inputs that bypass the mic amp and others run everything thru the mic preamp circuit --even line level signals-- and you just trim them down when the input is line level.

That shouldn't matter though. If you use the mixer's line level inputs as designed you should be fine.

I thought this was the case, I just wanted to be sure.
Thanks for the help!

[Remoteness]

We just did another successful recording with our "Budget24" rack.
The Budget24 rack has three modified XTA DS800s, two Alesis HD24XRs and a Roland M480...

The back of the rack has all the interconnected and patch bay for the M480.

We had to setup backstage for this loud rock show, so I brought in a couple of sMackie SR450s to do the do...

One speaker was patched out of the XTA listen out, so I can solo each individual input to the recorders.
The other speaker was connected to the Roland's (left) monitor output so I can hear the return from the recorders.

Next time I would like to use three speakers, one for the XTA listen and the other two for a stereo out of the mixer.

In any event, we used this single rack system as a splitter and adjusted the XTA DS800s just like you would any mic pre.

The only difference is you must get your levels before FOH or MON does their tweaks, so there are no suprises.

That being said, there were know complaints on the work-flow dynamic whatsoever.