Preamp headroom

[zhunter]

I am mostly playing a Cordoba GK with the onboard pup and preamp into a Schertler David/Unico. I routinely just plug straight in to the amp but also have occasion to want an XLR output so I can take better advantage of the XLR in channel on the Schertler as well as the added EQ options and added output a more sophisticated preamp brings. I have used a PADI for that purpose.

The problem is, even with the input gain on the PADI at the lowest setting, the PADI does not have sufficient headroom and distorts when I turn the guitar up past a certain point. A little over half way. When gigging it easy to get into trouble by just bumping the guitar volume a little past the sweet spot into distortion. I start getting crunch at about 1/2 guitar volume. I have verified the amp has plenty of headroom even when turned up high and getting boosted by the PADI. For now I have stopped using the PADI and, frankly things are working OK but I would still like to keep a preamp option.

At this point all of the whys probably aren't that relevant. I just need to deal with the input gain headroom issue. It may not be realistic to expect a preamp to handle the full gain my guitar preamp is capable of but I have to ask. Is there a preamp with more input headroom than the PADI? One that can handle the full output of a guitar preamp.

Thanks

hunter

[lschwart]

Originally Posted by zhunter

I am mostly playing a Cordoba GK with the onboard pup and preamp into a Schertler David/Unico. I routinely just plug straight in to the amp but also have occasion to want an XLR output so I can take better advantage of the XLR in channel on the Schertler as well as the added EQ options and added output a more sophisticated preamp brings. I have used a PADI for that purpose.

The problem is, even with the input gain on the PADI at the lowest setting, the PADI does not have sufficient headroom and distorts when I turn the guitar up past a certain point. A little over half way. When gigging it easy to get into trouble by just bumping the guitar volume a little past the sweet spot into distortion. I start getting crunch at about 1/2 guitar volume. I have verified the amp has plenty of headroom even when turned up high and getting boosted by the PADI. For now I have stopped using the PADI and, frankly things are working OK but I would still like to keep a preamp option.

At this point all of the whys probably aren't that relevant. I just need to deal with the input gain headroom issue. It may not be realistic to expect a preamp to handle the full gain my guitar preamp is capable of but I have to ask. Is there a preamp with more input headroom than the PADI? One that can handle the full output of a guitar preamp.

Thanks

hunter

You obviously don't need a preamp, so why don't you just get a dedicated EQ unit to give you the EQ you want and a DI box to allow you to use the XLR input of the amp?

On the other hand, if you do want to use a DI/Preamp unit, you could try the Radial PZ-Pre or PZ-Deluxe. I use the PZ-Pre with my GK Studio Negra and it has no problem handling the signal with the onbroad preamp when that preamp is set at around 2:00 or even a little higher. I use it with the "PZ" boost switch in the off position, and I use the channel volume controls to get an even balance with the other channel, which I use for a passive magnetic pickup with the "PZ" boost switch in (volume on channel 1 for the mag is set at about 2:00 and channel two balances that at about 10:00).

Other options are just to keep the preamp on your GK lower (easiest, but maybe a little noisy?), or I'm pretty sure you can go into the FX loop on the PADI, bypassing the preamp section, by (if I recall correctly) using an insert cable with the "ring" or send end running from your guitar to the TRS end, which when it's plugged into the FX loop should send the signal on to the EQ section of the PADI directly from the ring, no gain added. To do this you might have to plug a dummy jack into the PADI input to turn it on, but I don't recall--it's been a long time since I tried it. Maybe I'll try it tonight to see if I remember correctly.

Louis

[zhunter]

Originally Posted by lschwart

You obviously don't need a preamp, so why don't you just get a dedicated EQ unit to give you the EQ you want and a DI box to allow you to use the XLR input of the amp?

On the other hand, if you do want to use a DI/Preamp unit, you could try the Radial PZ-Pre or PZ-Deluxe. I use the PZ-Pre with my GK Studio Negra and it has no problem handling the signal with the onbroad preamp when that preamp is set at around 2:00 or even a little higher. I use it with the "PZ" boost switch in the off position, and I use the channel volume controls to get an even balance with the other channel, which I use for a passive magnetic pickup with the "PZ" boost switch in (volume on channel 1 for the mag is set at about 2:00 and channel two balances that at about 10:00).

Other options are just to keep the preamp on your GK lower (easiest, but maybe a little noisy?), or I'm pretty sure you can go into the FX loop on the PADI, bypassing the preamp section, by (if I recall correctly) using an insert cable with the "ring" or send end running from your guitar to the TRS end, which when it's plugged into the FX loop should send the signal on to the EQ section of the PADI directly from the ring, no gain added. To do this you might have to plug a dummy jack into the PADI input to turn it on, but I don't recall--it's been a long time since I tried it. Maybe I'll try it tonight to see if I remember correctly.

Louis

Yes I understand there are EQ and DI options. I have EQ and DI capabilities. I prefer a preamp for various reasons. Really I do just fine with no preamp and will play that way this weekend.

I like the option a preamp gives. Plus I have another guitar that has a pretty low output preamp and it benefits from having some preamp gain. The PZ-Pre looks like a great unit and would probably meet my needs if only it didn't rely on a wall wart. Still, I'll have to check one out. If I can make it to 3/4 on the volume control that leaves me the space I need for increasing volume since I like to run in the vicinity of 1/2.

Truth is I also take advantage of the crazy headroom in the Schertler and in rare occasions for the David have used a preamp to boost volume above the amps maximum. And the rest of the story. Last night we played a strange crowded and noisy room, I came in a little under amped (brought the David and not the Unico). The house PA was limited and we had to choose to not put guitar in the house. I needed a little more output and the preamp would have got me there but I couldn't push it since the input gain was maxed. We're back in this room next month and I'll simply bring the Unico.

I'd still like a preamp that could handle the GK output a little better but it may not be practical.

hunter

[jamison162]

Are you using a battery (a new, good, strong one)?? Try running off 48v phantom power from a mixer. Shouldn't have any headroom issues if all levels are set right.

[lmacmil]

I would contact Baggs tech support. They may be able to suggest something.

[Bluewyatt]

I'm no techie BUT - isn't the XLR in a mic level input? Also the XLR out will work just fine with a 1/4" line input. With the PADI you should plug into the effects return (if it has one).

[ljguitar]

Originally Posted by Bluewyatt

I'm no techie BUT - isn't the XLR in a mic level input? Also the XLR out will work just fine with a 1/4" line input. With the PADI you should plug into the effects return (if it has one).

Hi Bw...

No XLR input on a ParaDI (only XLR output).

[ljguitar]

Originally Posted by zhunter

I am mostly playing a Cordoba GK with the onboard pup and preamp into a Schertler David/Unico. I routinely just plug straight in to the amp but also have occasion to want an XLR output so I can take better advantage of the XLR in channel on the Schertler as well as the added EQ options and added output a more sophisticated preamp brings. I have used a PADI for that purpose.

The problem is, even with the input gain on the PADI at the lowest setting, the PADI does not have sufficient headroom and distorts when I turn the guitar up past a certain point. A little over half way. When gigging it easy to get into trouble by just bumping the guitar volume a little past the sweet spot into distortion. I start getting crunch at about 1/2 guitar volume. I have verified the amp has plenty of headroom even when turned up high and getting boosted by the PADI. For now I have stopped using the PADI and, frankly things are working OK but I would still like to keep a preamp option.

At this point all of the whys probably aren't that relevant. I just need to deal with the input gain headroom issue. It may not be realistic to expect a preamp to handle the full gain my guitar preamp is capable of but I have to ask. Is there a preamp with more input headroom than the PADI? One that can handle the full output of a guitar preamp.

Thanks

hunter

The ParaDI is out of headroom because you are turning the pickup's preamp up so high that it is overloading the gain section of the ParaDI. If you want more headroom on the ParaDI, then turn down the output of the pickup built into the guitar.

There is no 'rule' or 'principle' which would demand the input section (Gain) of an outboard preamp be able to handle anything we throw at it. In fact, it is designed to allow us to throttle back the input levels so we DO NOT overdrive the signal into the preamp. This is not a result of a faulty ParaDI, but can be evidence of either a bad battery in the guitar's preamp, or the signal of the guitar being too high, or the ParaDI's battery needing to be replaced.

The Master Volume (output) then allows us to regulate the signal to the input of the amp so we don't overdrive it as well.

You will need to balance the output of the guitar, the input of the preamp, the output of the preamp and the input of the amp (and the volume out of the amp via the speakers as well).

If it's working now, and you still feel the need for adding another layer of gain staging, then you will need to cut back somewhere - if not the guitar out, then the Preamp in.





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[lschwart]

Originally Posted by zhunter

Yes I understand there are EQ and DI options. I have EQ and DI capabilities. I prefer a preamp for various reasons. Really I do just fine with no preamp and will play that way this weekend.

I like the option a preamp gives. Plus I have another guitar that has a pretty low output preamp and it benefits from having some preamp gain. The PZ-Pre looks like a great unit and would probably meet my needs if only it didn't rely on a wall wart. Still, I'll have to check one out. If I can make it to 3/4 on the volume control that leaves me the space I need for increasing volume since I like to run in the vicinity of 1/2.

Truth is I also take advantage of the crazy headroom in the Schertler and in rare occasions for the David have used a preamp to boost volume above the amps maximum. And the rest of the story. Last night we played a strange crowded and noisy room, I came in a little under amped (brought the David and not the Unico). The house PA was limited and we had to choose to not put guitar in the house. I needed a little more output and the preamp would have got me there but I couldn't push it since the input gain was maxed. We're back in this room next month and I'll simply bring the Unico.

I'd still like a preamp that could handle the GK output a little better but it may not be practical.

hunter

I'm not sure I understand what you're trying to accomplish. Doesn't the GK Studio give you a signal strong enough to drive the input of the Schertlers (whether you go direct to the 1/4" inputs or use a DI to go into the XLRs)? If you can get a good signal at the input (just below clipping), you should be able to drive the power amp to full power (and that's pretty loud according to the specs). Another preamp won't help you get beyond that. You can't push the power amp farther than it will go, after all. There's nothing beyond maximum (just distortion and the effects of limiting).

Louis

[zhunter]

Originally Posted by lschwart

I'm not sure I understand what you're trying to accomplish. Doesn't the GK Studio give you a signal strong enough to drive the input of the Schertlers (whether you go direct to the 1/4" inputs or use a DI to go into the XLRs)? If you can get a good signal at the input (just below clipping), you should be able to drive the power amp to full power (and that's pretty loud according to the specs). Another preamp won't help you get beyond that. You can't push the power amp farther than it will go, after all. There's nothing beyond maximum (just distortion and the effects of limiting).

Louis

Doesn't the GK Studio give you a signal strong enough to drive the input of the Schertlers (whether you go direct to the 1/4" inputs or use a DI to go into the XLRs)?

No it doesn't. At least not as much as the Schertler will take.

If you can get a good signal at the input (just below clipping), you should be able to drive the power amp to full power (and that's pretty loud according to the specs). Another preamp won't help you get beyond that.

Yes it will. Schertler has room in both the preamp and power amp if I can get the signal to it. And yes it is pretty loud. We have three percussionists who were all mic'd up in the house so the amp was maxed out. Yes I should have brought the Unico.

Normally I can use the David to monitor and di to the PA for house sound in a bigger louder room. This room was unusual in that the PA was limited. I prefer to carry the David due to size and weight. Once I was topping out the Baggs and heard it distorting, I removed it and I played the entire show with just a cable into the amp. I got by but could have used a little more volume. When the room filled and the crowd got noisy, the David was not quite up to it. If I could have gotten a little more input, the David would have done the job. The Baggs runs out of headroom before the Schertler does.

And I didn't think the Baggs was broken. I have a pretty good idea how gain structures work and don't find the Baggs at fault. I am asking for more than it provides. It just doesn't have the headroom I would like. When I get the guitar over 1/2 volume it breaks up. I do run it on phantom power and the voltage is adequate according to Baggs. I have spoken with Baggs tech support.

What I am trying to do is identify a preamp with more input headroom than the Baggs.

Thanks for all of the other advice though.

hunter

[lschwart]

Originally Posted by zhunter

Doesn't the GK Studio give you a signal strong enough to drive the input of the Schertlers (whether you go direct to the 1/4" inputs or use a DI to go into the XLRs)?

No it doesn't. At least not as much as the Schertler will take.

If you can get a good signal at the input (just below clipping), you should be able to drive the power amp to full power (and that's pretty loud according to the specs). Another preamp won't help you get beyond that.

Yes it will. Schertler has room in both the preamp and power amp if I can get the signal to it. And yes it is pretty loud. We have three percussionists who were all mic'd up in the house so the amp was maxed out. Yes I should have brought the Unico.

Normally I can use the David to monitor and di to the PA for house sound in a bigger louder room. This room was unusual in that the PA was limited. I prefer to carry the David due to size and weight. Once I was topping out the Baggs and heard it distorting, I removed it and I played the entire show with just a cable into the amp. I got by but could have used a little more volume. When the room filled and the crowd got noisy, the David was not quite up to it. If I could have gotten a little more input, the David would have done the job. The Baggs runs out of headroom before the Schertler does.

And I didn't think the Baggs was broken. I have a pretty good idea how gain structures work and don't find the Baggs at fault. I am asking for more than it provides. It just doesn't have the headroom I would like. When I get the guitar over 1/2 volume it breaks up. I do run it on phantom power and the voltage is adequate according to Baggs. I have spoken with Baggs tech support.

What I am trying to do is identify a preamp with more input headroom than the Baggs.

Thanks for all of the other advice though.

hunter

I understand. And I can see why you don't want to just bypass the preamp in the PADI. The input on my Genz Benz Shen ProLT has a similar amount of room to spare on its 1/4" input, but there so much make up gain available at the power amp stage that I never have any problem with getting enough volume out of the thing going direct.

I do use the Radial and go into the XLR input, however, because I'm sending both of my guitar signals to the same input. The Radial might do it for you, if you can deal with the wall wart. As I said, it doesn't seem to have any trouble taking the output from the preamp in my GK Negra, which maybe has the same preamp/pickup as yours (?), a Fishman PreSys Blend. And when I go into the XLR input on the ProLT from there I can easily get near (and well over input clipping).

Louis

[Bluewyatt]

Originally Posted by ljguitar

Hi Bw...

No XLR input on a ParaDI (only XLR output).

I was talking about the Schertler David. I'm a little confused by the OP.

[zhunter]

Originally Posted by lschwart

I understand. And I can see why you don't want to just bypass the preamp in the PADI. The input on my Genz Benz Shen ProLT has a similar amount of room to spare on its 1/4" input, but there so much make up gain available at the power amp stage that I never have any problem with getting enough volume out of the thing going direct.

I do use the Radial and go into the XLR input, however, because I'm sending both of my guitar signals to the same input. The Radial might do it for you, if you can deal with the wall wart. As I said, it doesn't seem to have any trouble taking the output from the preamp in my GK Negra, which maybe has the same preamp/pickup as yours (?), a Fishman PreSys Blend. And when I go into the XLR input on the ProLT from there I can easily get near (and well over input clipping).

Louis

Well I guess I am actually abusing the Schertler but the thing seems to handle the abuse pretty well. And I only want to have the capability so I can get the sound out if I mis-estimate the house situation. Not a full time thing. Probably the ultimate lesson learned is bring the Unico since it covers about any situation.

I'll have to check the Radial out. I would probably like having the boost available although I usually control my level pretty well just by managing finger attack. Yes I have a Presys Blend also. It is actually a pretty hot preamp and has a lot more output than my Yamaha nylon AE. When using the Yamaha, I couldn't drive the David to the levels I got with the GK without the Baggs and that is where I got started using the preamp as a signal boost in the first place. I discovered I could beat up the front end of the Schertler and not get in trouble so I figured I could manage "overflow situations" by slamming the amp with the Baggs and my GK. Unfortunately the Baggs gets crunchy to early on the dial.

hunter