EVH 5150 amp schematics, real ones  [schematic]

Tube or solid-state, this section goes to eleven!
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Ice-9
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Post by Ice-9 »

Here are the real Fender amp schematics for EVH5150 amps and footswitch in case there any use to anyone.
They can be found on the evh/fender website, but for easy download and reference I put them here.
100w and 50w versions.
Attachments
EVH_5150III_Footswitch_Schematics.pdf
EVH 50w footswitch
(76.07 KiB) Downloaded 708 times
EVH_5150III_AmpHead_Schematics.pdf
EVH 100w head
(1.5 MiB) Downloaded 1272 times
EVH_5150III_50W_Vietnam_Schematics.pdf
EVH 50w head Vietnam
(176.24 KiB) Downloaded 702 times
EVH_5150III_50W_Mexico_Schematics.pdf
EVH 50w head Mexico
(175.19 KiB) Downloaded 811 times
It's fairly straight forward, if you want to start it , press start. You can work out the rest of the controls for yourself !

No silicon heaven ? preposterous ! Where would all the calculators go ?

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okgb
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Post by okgb »

the thank you button is not working for me today , so Thanks

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tarnow74
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Post by tarnow74 »

Those TL072 opamps in the 50w version probably sucks some tone when using the effects loop. I have the Hot Rod Deluxe which also comes with TL072 opamps in the effects loop and just jumping the effects loop with a patch cable made a lot of negative difference to the tone. I then bypassed the opamps in the circuit which worked fine. This will increase the effects send level and might be bad for some pedals. A more elegant fix would be to change the opamps to some newer high quality ones.

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deltafred
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Post by deltafred »

Hi and welcome to FSB.
tarnow74 wrote:Those TL072 opamps in the 50w version probably sucks some tone when using the effects loop.
You obviously don't understand how opamps work and have been drawn in by the "cheap opamps suck tone, expensive ones don't" hype.

The frequency response is purely dependant upon the feedback components around an opamp (as long as you stay within the design limits).
.... A more elegant fix would be to change the opamps to some newer high quality ones.
See above. Higher quality opamps will have better specs for noise, offset, CMMR, etc but will not affect the FR (in an audio circuit) one bit. Whether you notice any difference in these other parameters is doubtful.

You may however feel better and think it sounds better by throwing money at it.

It may be that the capacitance of your cables is causing high frequency roll-off of your signal when using the effects loop but no amount of opamp rolling will alter that.
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Post by Dirk_Hendrik »

Rather amazed by the "discrete" switching logic design which exceeds the amps audio circuitry in component count. Seems a task that can be done easily by a small CPU at a fraction of the price.

At the other hand, a device is as good as it's power supply. And therefore it's nice to see the power supply on the first page.
Sorry. Plain out of planes.

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Ice-9
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Post by Ice-9 »

Dirk_Hendrik wrote:Rather amazed by the "discrete" switching logic design which exceeds the amps audio circuitry in component count. Seems a task that can be done easily by a small CPU at a fraction of the price.

At the other hand, a device is as good as it's power supply. And therefore it's nice to see the power supply on the first page.
It does look rather complex, the two 50watt circuits are using a CY8C27433 micro to help with switching but the 100watt head isn't. Looking at the footswitch though there is a micro in there but I haven't had a good look over the schematics to see what is working what.
It's fairly straight forward, if you want to start it , press start. You can work out the rest of the controls for yourself !

No silicon heaven ? preposterous ! Where would all the calculators go ?

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