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Ampeg SVT3 Pro PREAMP OUT Balanced or Unbalanced? NEED A DEFINITETIVE ANSWER QUICK!!!

#61
agedhorse said:
This isn't going to help in this situation, it's a 1:1 ratio transformer that's intended for isolation only. It's not going to do anything for level matching.
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So it's NOT a standard line level signal? It needs a signal boost? I'm more used to dealing with studio gear and everything is (usually) more standarized there.

It it get's this complicated it's just yet another reason not to bother IMO. I really can't see why an SVT3 Pro can't deliver enough juice unless we are talking about a LARGE room with no FOH. And then it would require a cab that's specifically designed to handle that kind of wattage. Probably a heavy duty PA cab.

The SVT will probably sound better.
 
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#62
agedhorse said:
NEVER run the speaker output of a bridged amp into a DI. The pin 1 connection is tied to the 1/4" jack's sleeve terminal and will short the driven minus signal directly to console ground. This can damage the amp, the console, or both.
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I was talking about these:

6431ECB4-8FF8-4FD5-8970-73FE653B3125.jpeg
 
#63
okcrum said:
Enhanced, yes. I conceded you that point last page. As good as a properly terminated, balanced line, no. At least one end of the (transmission) line is terminated in some unknown impedance. There's no symmetry WRT ground in the system impedance because of the TS (one signal wire IS ground). You might get 30 dB with a perfect shield and perfect grounds on both ends. In reality what you'll get is a crap shoot. That difference in the shield hookup means a lot. Again, in this case, it's a 3-4 ft. run. I have to ask: What's your point?

Either of these hookups is IMO and IME a last resort. Any pro will put a transformer in at the unbalanced end and be done with it. :thumbsup:
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Sorry to ruffle your feathers. This seems to be another example where two people can't agree to agree. :bag: Have a nice day.
 
#64
Wasnex said:
Sorry to ruffle your feathers. This seems to be another example where two people can't agree to agree. :bag: Have a nice day.
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No feathers ruffled. I honestly don't get your point in this application.

If it's "this other way is better for long runs" we already agreed on that a page ago.
If it's "you don't understand the magic going on here", well, yes, I do, very well.

Seriously, I don't get your point. Tell me what it is.
 
#67
It doesn't sound like the SVT-3PRO is designed to work this way.

I think you should just use the 3PRO for your gig. Then I think you should sell it and shop for a proper preamp to match with your new Crown poweramp.
 
#68
ctmullins said:
I was talking about these:

View attachment 3254070
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Sorry, somehow the quotes got mixed up, sorry I edited it. My response was for this post:
--------------------------------------------
bhoff5150 said: ↑
OP - One way to do this would be to use the DI out of your SVT3-Pro into the crown. Speaker out of the crown to input of a Palmer PDI. Out of Palmer PDI to input of your cabinet. The palmer then sends a line to your FOH. This way you'd have the balanced input for the crown with a different signal going to FOH. I do this currently with an Ampeg PF-50T, and have done it also with a V4B and an SVT. The palmer is not cheap, but sounds ridiculously awesome with a speaker connected after it. Might not be viable for your upcoming gig, but you could do it for the next one.
------------------------------------------------------
 
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#70
two fingers said:
Keep in mind, as I understand it, the tube gain section is AFTER the preamp. So you won't be getting that part in the preamp out. That 12ax7 and 12au7 (I think I'm right on the second one.... it's been a long time since I owned mine) are used to drive the power section (MOSFET maybe?). There are 2 or 3 more 12ax7 tubes in the preamp section.

So, to me, it won't really be the sound of the SVT III through the cabs running it into a power amp straight off the preamp. It'll sound fine. But it just won't have the grit you could get through cabs otherwise.

Keep in mind, I last owned one in the late 90s. So I could be remembering incorrectly.
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Hey! Since you appear to understand some things, I have a wild idea. It's most likely stupid but since I have no electrical knowledge I have to improvise.

So we all know that an amp sounds the way it does not only because of the preamp but the power amp also. I have tried pairing up amps preamps with external power amps and to my disappointment always found out that it mostly drastically changes the amps behaviour (read it doesn't sound the way the whole amp does).

Is there a way to pick up the power amps signal (in OPs and my case, the SVT3PRO), attenuate it back to normal levels and resend it to the power amp this way? Probably it still wouldn't sound original but I would bet it would contain much more of the characteristics plus you could probably drive the amp as hard as you please and just use a super clean power amp with loads of headroom to just copy that sound to a louder degree. I can also tell that I am sometimes just slightly missing some headroom on a 8 ohm 410 with this amp, obviously only driving it on cca 250W or so.

It sounds unlikely to me that this is even possible but I can't deny I haven't been surprised many times what technology offers nowadays.
 
#71
Sparkl said:
Hey! Since you appear to understand some things, I have a wild idea. It's most likely stupid but since I have no electrical knowledge I have to improvise.

So we all know that an amp sounds the way it does not only because of the preamp but the power amp also. I have tried pairing up amps preamps with external power amps and to my disappointment always found out that it mostly drastically changes the amps behaviour (read it doesn't sound the way the whole amp does).

Is there a way to pick up the power amps signal (in OPs and my case, the SVT3PRO), attenuate it back to normal levels and resend it to the power amp this way? Probably it still wouldn't sound original but I would bet it would contain much more of the characteristics plus you could probably drive the amp as hard as you please and just use a super clean power amp with loads of headroom to just copy that sound to a louder degree. I can also tell that I am sometimes just slightly missing some headroom on a 8 ohm 410 with this amp, obviously only driving it on cca 250W or so.

It sounds unlikely to me that this is even possible but I can't deny I haven't been surprised many times what technology offers nowadays.
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It's POSSIBLE, but there are a whole bunch of technical hurdles that mostly result in expensive repairs. This method too is unlikely to result in the results you desire.

Without understanding the details, it's likely to end poorly.
 
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#72
rickdog said:
A balanced input just uses the difference between the two signal lines. If you're sending a balanced signal into it, the two signal lines have the same signal, just opposite polarity (positive on one, negative on the other).

You can connect a single-ended signal to the balanced input, one signal line is the signal and the other is ground (no voltage). You lose the noise canceling benefits of a balanced line (usually not a big issue for a short cable run), but it works just fine.
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This. Try it and see for yourself. We did this all the time for returns down a snake into a pile of PA amps. Always worked fine even for that. It's not technically correct, but we never had a problem with it. Test it 'before' you use it at a gig. We were using a DBX160 as a line driver.

Otherwise, be the pro and rent a head from Backline or SIR, etc., that will do what you need it to do and twiddle with your new set up when your not under the gun. You don't need the reputation of being a scatter brain at an important gig. It's not worth it. Concentrate on your playing! That's why your there. Yes?
 
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#74
agedhorse said:
It's POSSIBLE, but there are a whole bunch of technical hurdles that mostly result in expensive repairs. This method too is unlikely to result in the results you desire.

Without understanding the details, it's likely to end poorly.
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So I am going to ask a Sherlock Holmes question - what would be an approach to make the SVT3Pro into a 1000W amp (the number is generic)?

Buying a 1000W amp is an obvious answer but honestly, there is something about the SVT3Pro character that none of the other Pro series has. It comes the closest to the big CL and it comes close enough for my desires. Yet I would actually like to have the option of more headroom for some specific cases.
 
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#75
Sparkl said:
Hey! Since you appear to understand some things, I have a wild idea. It's most likely stupid but since I have no electrical knowledge I have to improvise.

So we all know that an amp sounds the way it does not only because of the preamp but the power amp also. I have tried pairing up amps preamps with external power amps and to my disappointment always found out that it mostly drastically changes the amps behaviour (read it doesn't sound the way the whole amp does).

Is there a way to pick up the power amps signal (in OPs and my case, the SVT3PRO), attenuate it back to normal levels and resend it to the power amp this way? Probably it still wouldn't sound original but I would bet it would contain much more of the characteristics plus you could probably drive the amp as hard as you please and just use a super clean power amp with loads of headroom to just copy that sound to a louder degree. I can also tell that I am sometimes just slightly missing some headroom on a 8 ohm 410 with this amp, obviously only driving it on cca 250W or so.

It sounds unlikely to me that this is even possible but I can't deny I haven't been surprised many times what technology offers nowadays.
Click to expand...

I'm sure it would be possible with the right equipment but every gain stage adds noise. So amplifying, then attenuating and then amplifiying back up again might give you an unacceptable signal to noise ratio.
 
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#76
agedhorse said:
It's POSSIBLE, but there are a whole bunch of technical hurdles that mostly result in expensive repairs. This method too is unlikely to result in the results you desire.

Without understanding the details, it's likely to end poorly.
Click to expand...


Are there no DIs that can safely work on an amp with a differential output? Is this a potential market opportunity?

I guess the limiting factor in this case is the SVT3-Pro output section probably requires a speaker load and being pushed to it's rails to develop the desired feel. So a speaker level DI really gets you nothing. Still seems like a lot of players want a speaker level DI that can be used safely with any amp.
 
#77
Wasnex said:
Are there no DIs that can safely work on an amp with a differential output? Is this a potential market opportunity?

I guess the limiting factor in this case is the SVT3-Pro output section probably requires a speaker load and being pushed to it's rails to develop the desired feel. So a speaker level DI really gets you nothing. Still seems like a lot of players want a speaker level DI that can be used safely with any amp.
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There would be little to no benefit to taking a speaker level DI off of a PA Power Amp. The practice of using a Speaker Level DI is intended to capture the added character of a tube power section. Outside of a few particular examples (GK RB series, etc), solidstate poweramps don't usually offer much in terms of character to be captured and sent to the PA.
 
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#78
I hope this clears up the often misunderstood XLR/Balanced thing.

XLR and Balanced usually go together but are two different things. XLR is a three pin connector. Bal/Unbal is an electrical circuit. XLR can be balanced or unbalanced depended on the amp/preamp circuit but XLR is usually balanced. Just because there is an XLR connection doesn't guarantee it's a balanced circuit. I.E. You can plug an XLR to 1/4" adapter into a balanced XLR output and it then becomes "unbalanced circuit".

The difference between balanced and unbalanced is that the balanced method will provide noise rejection and a 6dB boost over unbalanced. That's it. The longer the cable run, the more likely you'll want noise rejection and the 6dB boost of a three wire balanced circuit.

This isn't the ultimate answer you were looking for but I hope it at least helps.

I'm sure you're aware that it's always a high risk to make a major change that hasn't been tested or rehearsed just before an important event. Taking that risk is your call.
 
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#79
NKBassman said:
There would be little to no benefit to taking a speaker level DI off of a PA Power Amp. The practice of using a Speaker Level DI is meant to capture the character of a tube power section. Outside of a few particular examples (GK RB series, etc), solidstate poweramps don't usually offer much in terms of character to be captured and sent to the PA.
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I understand and totally agree...we're talking about a fairly unique situation I would try to help someone with, but I would not do this myself. I would just pull out my SVT8-Pro and call it a day :woot:.

My inquiry was intended to tie in with @Sparkl 's desire to capture the sound and feel of the 3-Pro as a complete system, rather than just the response of the preamp. I.E. He feels the 3-Pro output section has something unique to offer that is lost when you take the pre out and feed a big power amp.

So how do you capture that feel? Unfortunately I don't think a speaker level DI is the answer in this application. I don't think the output section will develop it's characteristic sound and feel unless it is loaded with speakers and pushed hard.

Theoretically you could hook up the output section of the 3-Pro to a big power soak and drive the Crown with an attenuated output from the power soak. That should get you closer, but now your dealing with a rather large and expensive load box that has to be custom manufactured.
 
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