Here is a ENGL clone type preamp I made partially from what I could make out from high res E1 gut shots posted on the net and the rest was guess work/trail and error etc... I have added a presence knob but that could be left off for a 5 knob build...



Demo using direct out and cab/speaker impulses - dry

http://dl.dropbox.com/u/11178619/E1-%20Impulse2.mp3

Sounds great. I cant wait for a layout.

cool,  now wheres the impulses schematic?...

Quote from: deadastronaut on August 13, 2012, 06:53:48 AM
cool,  now wheres the impulses schematic?...

It's a Marshall 4x12 loaded with Celestion 25w greenbacks... Now go build one

Or, you could help me tweak that cab simulator to sound better..? 

On a serious note: I am building a power amp section for these preamps - 100w using the TDA7294

  ok..

Quote from: deadastronaut on August 13, 2012, 07:46:31 AM
ok..

ok is a broad term..? ok what? 

lol you replied/edited too quick...



that sounds good, proper amps for these emulators....nice!   (ive never built an amp)


as for helping out, i'm a little busy at the mo (with my diy sustainer) its coming along nicely.(and not the spec thats commonly tried n tested and leads to B+E failure)..but i'll get back to ya as soon as i can....very interested.

Look in the datasheet for the TDA7294... complete board layout and schematic! good enough for Line 6 and other amp manufacturers then should be good enough for me! 100w should blow your face off

http://www.datasheetcatalog.org/datasheet/SGSThomsonMicroelectronics/mXqwvzw.pdf

cool, should be good for all these emulators,  what speaker setup are you aiming at?...

Quote from: deadastronaut on August 13, 2012, 09:18:56 AM
cool, should be good for all these emulators,  what speaker setup are you aiming at?...

Just thinking of building a head... I have a 4x12 cab already loaded with greenbacks. I haven't ever built an amp either other than some real small stuff but I figured I would give it a try. Pretty set on it the more that I think about it so if anybody has any tips please do share   I know I want to put an FX loop in it and multiple channels with foot switches and maybe a built in TS808 or some sort of jfet OD/boost, something to  tighten up the bottom end and give it a little more bite. I like the ENGL type clone preamp over all the others I have built but the 5150 is a close second. The ENGL has more gain and tighter bottom end than say the Bogner! This one that I built has an amazing amount of gain actually, maybe because I added the extra J201 - T5 on the schematic? Not even using a TS on the demo I recorded...!

Jok3rx i will be building your engl 1-6-2013 version schematic.Is it the final revision? perf layout is finished and i'm preparing the parts now.

I;'ve just ordered parts for this pedal and tda7294 power amp. Have you built it? What;s your opinion?

btw - I used a 100k gain pot and don't even bother with D1, D2 and D3 unless you use BAT85 or some other similar schottky diodes. The best possible match for the jfets would be 2SK30A-R but good damn luck finding those. I have a layout for it but I don't like it so no post...

Cool good work mate
This looks and sounds amazing

@Jok3rx.. Is this the same one you ended up developing on your Black Forest thread?

The link to the TDA7294 did not work for me, can anyone else see it?

Quote from: caspercody on March 22, 2013, 08:43:39 PM
@Jok3rx.. Is this the same one you ended up developing on your Black Forest thread?

The link to the TDA7294 did not work for me, can anyone else see it?

Rob,

I posted this a long time ago on August 12, 2012 and started the Black Forest post on September 01, 2012. This is not the same as the one in the Black Forest thread... This is a AMT E1 clone that I traced from pictures posted in another forum. There are no bugs on this to report going by my build... A little less gain than the E3 Russian schematic but no hum either.

Keep in mind that AMT designs these pedals with 2SK208-R for a reason! J201's are easy to get but have more noise and probably not quite as warm sounding. 2SK208-R is the same as 2SK879-R and for the through hole version it's 2SK30A-R... All not easy to come by! I would experiment with different jfets but you can use J201's, they sound pretty good.

Seems like the link to the TDA7294 is dead now... google it, you will find it.  

BTW - If you look in the data sheet for the TDA7294 there is a complete board layout if I remember correctly..  

They use these in a lot of amps like Line 6 and others...

Here's one I found after looking for about 2 minutes... they are all over the place!
http://1stmanual.blogspot.com/2013/01/stereo-80watt-audio-amplifier-tda7294.html

Here is a link to the datasheet http://www.st.com/web/en/catalog/sense_power/FM125/CL1503/SC979/PF74359?s_searchtype=keyword

If you want to build a power amp I would look on ebay... They have full kits for real cheap! Also check out the LM3886.


Edit: Cool project would be a stereo 4 channel high gain amp head with FX loop, built in cab simulation and reverb... Don't worry, I ain't opening that can of worms!

Awww c'mon Jim, open it 

Quote from: pakrat on March 22, 2013, 10:00:41 PM
Awww c'mon Jim, open it 

Ummmmm.....NO!