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Old 28th June 2008, 12:20 PM   #121
Nordic is offline Nordic  South Africa
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JP you don't maybe have two of those fets for me? The only place I can source them here they are $2 each and I need to buy a minimum of 10, which is tight for a pensioner...

I am haveing a horrible three days... now on 3rd rebuild of a MXR dynacomp pedal... each with varying degrees of failure

Just came back from the printing shop with some press and peel for a third and final attempt... this time I went for 1.3mm traces and 1.3mm isolation... should be a bit more DIY friendly... there is quite a diffirence in designing a board for home etching and soldering and one that would come masked from a factory.
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Old 4th July 2008, 09:20 PM   #122
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Thank you Mr. Hugsley. Now I think I've got all I need to know to design and build what I want.
Wish I still had my O-Scope though. Sure would simplify things. But I sure this will work just fine.

Thanks again,
Ken
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Old 24th July 2008, 02:01 PM   #123
maniax is offline maniax  Indonesia
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Hi can u help me???? please....

Please send me an e-mail at maniaxwanita@yahoo.com including the Jfet guitar preamp schematic of the page

www.bossaboa.dk/preamp.gif


because I donīt open this page from my home
Thank you very much
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Old 24th July 2008, 04:00 PM   #124
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That site is closed, apparently. I get a "server does not exist" error message.
But if you want a nice FET preamp, this very thread has the best one I have found online, and I've done a LOT of searching. Plus it has a complete description of construction and the theory behind it as well.

Ken
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Old 24th July 2008, 08:04 PM   #125
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Default Re: Updated schematic for FET guitar preamp.....

Quote:
Originally posted by jazzpeter65
Updated schematic for FET guitar preamp:
I've made a few adjustments and eratas since the first version.
This preamp sounds great - forget about opamps for a moment a try this one. It's warm, smooth and tubey. Very simple circuit with few phase invertion stages.
The thread is quite interesting but I wonder which of the preamps were actually build and work correctly. In the schematic provided by Peter there is a mistake that will cause that the tone controls wont work; resitors R16, R17 and R18 should be connected to the output of U1B (which is how Albert Kreuzer's preamp is designed). Have you noticed this?
I'm looking for a bass guitar preamp (a little bit more advanced than the one by Albert). If you have any ideas, please post them here.

Mark
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Old 24th July 2008, 08:18 PM   #126
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I also simulated one of the preamps mentioned in the begining of the thread; the Runoffgroove Cabsim. This is typical cabsim and I think that it shouldn't be used as a preamp (especially that it has gain < 1). Attached is frequency response of the cabsim.

Mark
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File Type: png cabsim02.png (13.9 KB, 1124 views)
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Old 25th July 2008, 12:08 AM   #127
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I recommend JP Hugsley's preamp. I've built two of them now and they work Great! There's one in my Strat and I built another for a friend who plays bass. The tone section is easily altered to suit the application and Mr. Hugsley explains exactly how to do it.

Ken
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Old 28th July 2008, 07:21 PM   #128
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I simulated the preamp. Attached is the frequency plot of the preamp. Looks good but I'm worried about two issues; the gain changes with the frequency and it's x1.8 at low frequencies and x2.5 (and not x6.5 as mentioned in one of previous posts), and other issue it that it's quite difficult to buy J201 (with other transistors I get much lower gain).
But still it looks interesting.

Mark
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File Type: png hugsley.png (16.1 KB, 1080 views)
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Old 28th July 2008, 07:30 PM   #129
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JP Hugsley, on one of images attached I see that you have a SMD version of the board. I wonder which transistors are used there. Is there a SMD version of J201?

Mark
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Old 29th July 2008, 06:58 PM   #130
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I found out that SST201 (or MMBFJ201) is a SMD replacement for J201. Also not that easy to purchase.

Marek
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