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Topic: Question for Jody Carver/Fender |
Lloyd Karenke
From:
Eagle River, Wisconsin, USA
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Posted 16 Feb 2004 7:02 pm |
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Jody...I have a Fender Princeton 65 amp and would like to install a headphone jack and cut out the spkr when using. Could you instruct me as how to install it? What type of input jack (mono/stereo) etc.? Will using the headphones put a strain on my output transformer if it disconnects the spkr? Please advise on how to install.
Thanks!
Lloyd |
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John Bechtel
From:
Nashville, Tennessee, R.I.P.
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Posted 16 Feb 2004 9:40 pm
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I admit that I don't know the answer to your inquiry, but; it sounds like a dangerous undertaking to me! Why not just invest in a Practice-Headset? “BJ”
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“Big John” Bechtel
http://community.webtv.net/KeoniNui/BigJohnBechtels
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Jody Carver
From:
KNIGHT OF FENDER TWEED
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Posted 17 Feb 2004 3:32 pm
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Lloyd
I am sorry to say that I am not qualified to
answer your question. I was a salesman for
Fender with a limited amount of technical knowledge.
I am certain there are a few people on this Forum who can help you and answer your question. Sorry I couldn't be of any help.
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Ken Fox
From:
Nashville GA USA
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Posted 17 Feb 2004 6:32 pm
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Lloyd, I downloaded a schematic from the Fender site for the Princeton 65. It appears to be a transistor amp, not a tube amp. Is that correct?
If so you have a "preamp output" and a "power amp" input on the front panel. You can plug a short cord, or just a bare 1/4" jack into the "power amp" input. That will disconnect the pre amp from the power amp. Now you will have no speaker sound to contend with. Next, you can use the "preamp output" to feed a headphone amp. It may be a bit of a hot signal for the headphone amp, if so a pad (resistor network) can be built to pad the output a bit. The preamp output is typically less than 1 volt RMS into a very high impedance. It will not drive low impedance heaphones directly, as it loads the source too heavily. You need an amp/buffer in between it and the headphones for proper match. Most headphone amps are designed for a low level guitar signal, not a preamped line out (such as the "preamp output"). That is why some overdrive/distortion may occur. |
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Ken Fox
From:
Nashville GA USA
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Posted 17 Feb 2004 8:00 pm
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This looks like a nice headphone amp and has line input, mike input and instrument inputs:
Product Description
The PM350B is the latest unit in the popular lineup of Rolls personal monitor devices. The PM350 mixes 3 signals; a 1/4 in. stereo or mono line level, an XLR mic, and stereo (TRS) 1/4 in. unbalanced instrument level signal together to 1/4 in. headphone and 1/8 in. earphone outputs. It also now has Left and Right TRS balanced stereo outputs. All signals have individual level controls.
The line input is switchable from stereo to mono via jumper on the side of the unit. The mic input has a hardwired pass through, and the instrument input connects to a balancing transformer and is output via an XLR jack.
This unit is perfect for any instrumentalist/singer needing to mix their mic signal with their instrument and the main monitor mix, plus send their mic and instrument signals to the main mixing board.
Rolls Mixers
Rolls professional mixers are, like all Rolls products, conceived, researched, designed and manufactured for quality — at a popular price. Each are housed in steel chassis, use sturdy glass-epoxy circuit boards and contain the finest components. Finally, their low cost is achieved by high productivity manufacturing.
Technical Description
Max Input Level: -20 dB XLR, 40 dB Line and Instrument
Inst. Input Impedance: 50K W
Inst. Frequency Response: 50 - 15kHz +/- 3 dB
Output Impedance, Headphone: 10 ohms
Output Impedance, Inst.: 600 ohms
Gain: 15 dB 1/4 in., 50 dB XLR
Hdphn Freq. Response: 20 - 20 kHz
S/N Ratio: 90 dB
Power: 9 - 18 VDC
Size (W x H x D): 4.5 x 3.3 x 1.5 in.
Weight: 1 lb. (.45 kg)
http://www.zzounds.com/item--RLLPM350
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Lloyd Karenke
From:
Eagle River, Wisconsin, USA
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Posted 17 Feb 2004 8:05 pm
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Thanks anyway Jody! Big John...the trouble is that I run my steel to one input and my CD player to the other so they both come thru the spkr. I tweak my amp (steel input) for different songs.
Ken...I have 2 inputs on the left side and 3 inputs on the right side. (Foot switch, out, in). This is the preamp. when I plug a jack into the foot switch, it cuts out the spkr but nothing comes out of the "out". When I plug into the "in" then the spkr comes back on. Why couldn't a headphone jack be installed that would disconnect the spkr (like on my CD player) and play thru the headphones? I read that this is not good to do on some amps because of the output transformer not having a load on it. Yes...my amp is all transistor. Please advise.
Yhank you!
Lloyd
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Lloyd Karenke
From:
Eagle River, Wisconsin, USA
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Posted 17 Feb 2004 8:10 pm
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P.S...Ken...I already have a 4 channel headphone amp...thanks!
Lloyd |
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Ken Fox
From:
Nashville GA USA
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Posted 17 Feb 2004 8:55 pm
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The "in" should be a power amp in. Plugging just a cord or jack in there should cut the amp off from the preamp. Now your mixed signal should be at the "out" or preamp output. Just plug that into the headphone mixer/amp. Nothing should plug into the footswitch jack for this operation.
A transistor amp will run fine with the speakers unoplugged. Also with the above procedure the power amp is still connected to the speakers, but no signal gets there when a dummy plug or cable is inserted in the power amp input jack.[This message was edited by Ken Fox on 17 February 2004 at 08:57 PM.] |
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Lloyd Karenke
From:
Eagle River, Wisconsin, USA
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Posted 18 Feb 2004 10:07 am
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YEP! Ok...ten four...that works Ken! Only thing is...it comes thru one side of the headphones (mono). No big deal but would like to have it come thru to both ears. You say it wouldn't hurt to disconnect the spkr...could I then just go ahead and install a stereo female jack that would disconnect the spkr and run straight into my stereo headphones? If I cut the volume down...would this still over drive the headphones? What problems do you see with doing that?
Thanks again!
Lloyd |
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Ken Fox
From:
Nashville GA USA
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Posted 18 Feb 2004 12:09 pm
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| I would never use a speaker output for headphones, to much power there and potential for blown earphones and/or your ears! The method I suggested just disconnects the amps preamp from the power amp input and speakers. The signal out of the preamp out is mono. Do you have a left and right input on your stereo headphone amp? If so y-cable the preamp out to the two inputs of the unit. That should give you volume on both sides of the headset. [This message was edited by Ken Fox on 18 February 2004 at 12:49 PM.] |
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Lloyd Karenke
From:
Eagle River, Wisconsin, USA
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Posted 18 Feb 2004 6:58 pm
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Thanks Ken...yeah...I can do that! Thanks for all the input!
Lloyd |
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Lloyd Karenke
From:
Eagle River, Wisconsin, USA
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Posted 23 Feb 2004 7:39 pm
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Please close!
Lloyd |
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