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Author Topic: Mesa Recto/FET Homemade  (Read 42460 times)


THChrist

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Re: Mesa Recto/FET Homemade
« Reply #1 on: December 26, 2008, 11:27:27 PM »
sounds good, any layout or schematic?

THChrist

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Re: Mesa Recto/FET Homemade
« Reply #2 on: December 27, 2008, 10:51:32 AM »
thanks, it sounds amazing. how does it sound with the cleans?

mensur

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Re: Mesa Recto/FET Homemade
« Reply #3 on: December 27, 2008, 04:36:14 PM »
With humbackers it is good for dirty blues, but with single coils it's a beauty...

mensur

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Re: Mesa Recto/FET Homemade
« Reply #4 on: January 11, 2009, 07:08:23 PM »

J M Fahey

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Re: Mesa Recto/FET Homemade
« Reply #5 on: January 12, 2009, 09:04:18 AM »
Mansur, just this: EX-CEL-LENT !!!! Congratulations. Please tell us something about the power amp, speakers,your guitar,  and how the demo was recorded, everything has influence on the final sound. Congratulations again.

mensur

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Re: Mesa Recto/FET Homemade
« Reply #6 on: January 12, 2009, 01:43:06 PM »
Thanx,
Power amp is TDA7294(100W Mosfet), mine design,
Cab is 2x10''(SAL speakers), again mine design(oversized cab, to create much more bass),
Guitar is Squier Strat loaded with Di'Marzio,
It was close micked with regular PC mic.

armstrom

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Re: Mesa Recto/FET Homemade
« Reply #7 on: January 14, 2009, 03:40:56 PM »
Sounds great for really high gain stuff... I know you already answered the question about clean sounds, but do you have any samples? I'm curious how well it cleans up. Congrats on a great build :)

rowdy_riemer

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Re: Mesa Recto/FET Homemade
« Reply #8 on: January 30, 2009, 10:16:45 AM »
What supply voltage do you use?

mensur

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Re: Mesa Recto/FET Homemade
« Reply #9 on: January 31, 2009, 09:24:26 AM »
It's 24 volts,LM317 regulated supply.

Muthauzem

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Re: Mesa Recto/FET Homemade
« Reply #10 on: February 16, 2009, 08:49:11 PM »
In The Schematics... You use Trimmers for four of the JFETs. What are you aiming for? I'm Interested in building it...

Bye

armstrom

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Re: Mesa Recto/FET Homemade
« Reply #11 on: February 17, 2009, 12:16:23 AM »
I don't want to speak for the OP, but I can answer your question. When you see trimmers like this on the drain of a JFET gain stage they're typically there to adjust the bias point of the stage. The electrical characteristics of JFETS vary greatly from one to the next (even of the same model!) so one "work around" is to provide a trimmer for the source resistor in a "self bias" configuration. The trimmer is adjusted until you see about half supply voltage on the drain pin and the stage is considered "biased". In reality, these trimmers are usually much larger than they need to be and that can make it very difficult to dial in a good bias point (the trimmer is too sensitiive). You see this approach a lot with designs from runoffgroove.com . You will see a lot of heated debate about the use of trimmers in this way. Some people think it's lazy design, others think it provides greater tolerance of variance in JFET parameters. I believe that for home-built DIY stuff all that matters is if the circuit sounds good to you when you're done. Now if we're talking about a production circuit meant for mass production, then the game changes.

mensur

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Re: Mesa Recto/FET Homemade
« Reply #12 on: March 12, 2009, 12:30:10 PM »
Here more new clips.I modified the preamp to be more aggressive, lots of gain, thick low end, please tell me your comments:
Memara Beest 100 Clip 1.mp3
Memara Beest 100 Clip 2.mp3
Memara Beest 100 Clip 3.mp3

350606

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Re: Mesa Recto/FET Homemade
« Reply #13 on: March 15, 2009, 02:24:38 PM »
Hello! Nice build! I'm gonna try it, but i have a problem with the layout. My printing program says that it should be 1 meter long! I don't think that's the real size, so, could you post it with the real size? At least tell us what size it should be so we can change it. Thanks!

EDIT: Now that I see, that wasn't the printable pcb... Could you post it, please? Thank you!
« Last Edit: March 15, 2009, 08:41:49 PM by 350606 »

J M Fahey

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Re: Mesa Recto/FET Homemade
« Reply #14 on: March 15, 2009, 07:37:18 PM »
Hi 350606. I guess Mensur saved his awesome preamp at 600 DPI resolution, which is great for printing but too much for screen viewing. I think a good screen resolution is 72 DPI. Dividing the width in pixels by 600 gives me a board length of around 7.4 inches (188 mm), which is most reasonable. Anyway it´s just an educated guess. If he had used any DIPs it would have been easy to check for .1" pin spacing or .3" width. Bye.