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MandoDiddle
Mar-31-2004, 6:19pm
I just purchased a Schertler Dyn-m pickup (Contact dynamic mic) for my mandolin. I am not using a preamp, just a one foot adapter cord (XLR to 1/4"). I am getting distortion from my Strawberry Blond amp that sounds like the amp's preamp is getting driven too hard. Is this possible? The Schertler is sending a low impedance signal. Has anyone experienced this? Thanks for any help, I'm frustrated.

Tbone
Mar-31-2004, 7:42pm
I've used my schertler into a strawberry blonde once as well, and I had no problem. I think its probably the connection you are using. I can't remember, but I don't think there's an xlr into the strawberry. I used a pre amp - plugged the schert into the preamp, and went 1/4" out to the amp, I think, with no problem.

Actually, if I think about it, it kinda makes sense. The low impedance changes to a high impedance, effectively cutting the voltage delivered to the preamp. So, the preamp would have to work harder. But I don't know for sure.

MandoDiddle
Mar-31-2004, 8:49pm
Tbone,
Thanks for the reply. I think you may be right. I think my line matching transformer may be fried. Anyway, I'm going to order a new one and see if I get any better results. Thanks.

Gail Hester
Apr-01-2004, 4:01am
William, I think Tbone is correct and I donít think the way you are connecting things will work even with a new adapter. #

The XLR to ľ phone plug adapter is not an impedance matching transformer; itís simply an adapter with a tiny, relatively poor quality audio transformer. #The problem with connecting your Schertler this way is that youíll get about a minus 10dB attenuation due to load loss. #Load loss in this case is the relationship between the source impedance (microphone or in this case the Schertler pickup) and the load impedance which is the impedance of the primary winding of the audio transformer in your adapter. #When you do the math for normal values it ends up being about -10dB.

Acoustic amps like the SWR, I have one too, are intended for guitars with piezos and on-board pre-amps. #Long story short, the signal to the amp is just too small unless you use a preamp or an active direct box, or if you get another amp that has an XLR input and can plug your Schertler directly into it. #This also answers your question in the other thread as to why Chris uses an active direct box last in his signal chain. #Iíve tried it the way you are doing it and I had the same poor results. #I also use an XLR to ľ phone plug adapter so that I can use a volume pedal or whatever else but I ended up using a preamp as the final device to my amp and now it works great.

-Chuck (not Gail)

MandoDiddle
Apr-01-2004, 9:14am
Chuck, thanks a million. I guess I just better bite the bullet and get the pre amp II. Chris seems to use his pre amp at the front of the chain (pre amp, tuner, direct box, amp). I'm not sure what you are saying when you say you use the pre amp at the end. Wouldn't you need to convert the low signal with a pre amp to line level before you could use a tuner or volume pedal? Hey, once again thanks.
Bill

Gail Hester
Apr-01-2004, 3:02pm
[Quote from other thread] Schertler says that this is Thile's setup: Schertler Pre-Amp II, a Boss TU-2 pedal tuner, and a BSS direct box. (I'm not sure why he needs the direct box after the tuner) He also uses a Shure KSM44 mic for solos.

Bill, Iím not trying to be a ďknow it allĒ or be negative but just trying to save you some time, money and frustration. I donít think the Schertler preamp will work for you because it only has XLR/balanced outputs and the Strawberry Blonde only has unbalanced 1/4 phone inputs. I think the Schertler preamp has little practical use for that reason. Itís designed to plug in the Schertler pickup and then go directly to a PA system or to an amp with an XLR input, but then you canít use any pedals. You need a preamp that has the option of an unbalanced output or you need to get a different amp that has a balanced input if you want to use the Schertler Pre-Amp II.

As far as Chrisís setup, itís different than what you need since he doesnít use backline amplification but rather goes through his preamp, pedals and then into the house system possibly using the active direct box you mentioned. His stage volume is achieved with monitors. I canít claim to know for sure but I thought he used a RANE AP13 ACOUSTIC INSTRUMENT PREAMP and also a volume pedal. The Rane is a pricey, rack mounted unit with lots of features such as stereo ľ" line-level outs for amplifier feed and stereo XLR mic-level outs for direct console patching and onboard 7 band stereo EQ. I'm not sure if he still uses the Rane but he used to.

-Chuck

MandoDiddle
Apr-01-2004, 5:34pm
Chuck, I hope I didn't give the impression that I thought you were a know-it-all. I don't and I really appreciate your thoughts. I think your right on target. Thanks.
Bill

Gail Hester
Apr-01-2004, 6:51pm
Bill, you didnít give me that impression, not at all. I just wanted to let you know that I was sincerely trying to help and not just spouting off.

-Chuck

Tbone
Apr-01-2004, 7:41pm
Glad you guys could hug and make up.:;):

Does anyone make pedals/fx units with XLR inputs? How bout wireless transmitters? I'd love to go wireless, but they all have 1/4" inputs, that I've seen.