wwwdotcomdotnet Posted June 5, 2007 Report Share Posted June 5, 2007 My friend and I want to build amps, specifically this one: Marshall 1974. We have both been doing plenty of research (well, mostly him so far haha), and both of us know our way around a soldering iron and circuit schematic pretty well, however this schematic is a bit over my head. I know there are a bunch of people here who have made amps before, could you guys offer some pictures of your amps, that is, the actually wiring? I want to see a schematic, and the actual build if you don't mind sharing because that would greatly help me put the theory to an image in my head. If you want your designs kept secret I completely understand too, but any advice you have to offer would be greatly appriciated. I know the parts I need, but now I just need a pep talk basically haha. Thanks! Quote Link to comment Share on other sites More sharing options...
curtisa Posted June 5, 2007 Report Share Posted June 5, 2007 You're certainly jumping in the deep end building a valve amp! Have you built any electronics projects of any kind before? Have you had any experience with this sort of thing? Building a valve amp isn't exactly for the faint hearted, and it's certainly a lethal project if you're not completely au fait with the risks! My main rig is a DIY job. It's essentially the 1st and 3rd channels of a Soldano X88R preamp (plus some tweaks here and there), married to a stereo valve poweramp which was a sort of whacky bastard child of a Mesa Boogie 50/50 and a Soldano SLO100. Although the schematics for those amps are easy to find floating around, I don't have any complete schematics of my actual rig as the project kinda "evolved" over time, but I could take some photos of the guts of it and post them if you like? Dunno how relevant they'll be with respect to the Marshall 1974, but it may give you an idea about component placement and layout? Quote Link to comment Share on other sites More sharing options...
wwwdotcomdotnet Posted June 5, 2007 Author Report Share Posted June 5, 2007 that would be great, if you dont mind Quote Link to comment Share on other sites More sharing options...
wwwdotcomdotnet Posted June 5, 2007 Author Report Share Posted June 5, 2007 I realize a lot of veteran members will be avoiding this topic because its been posted numerous times, but all I am really looking for is a physical picture of the wiring from anyone will to offer it. Quote Link to comment Share on other sites More sharing options...
mikhailgtrski Posted June 5, 2007 Report Share Posted June 5, 2007 Check it out: metroamp forum Quote Link to comment Share on other sites More sharing options...
wwwdotcomdotnet Posted June 5, 2007 Author Report Share Posted June 5, 2007 hmm. those amp kits they have on their retail site are enticing. http://store.metroamp.com/index.php?cPath=44 i wonder how much i could put that parts list together for if i ordered everything myself individually? Quote Link to comment Share on other sites More sharing options...
Geo Posted June 5, 2007 Report Share Posted June 5, 2007 (edited) Hey man... my one piece of advice... DO IT!!! I haven't built an 18watt, but here's a link to a photo of the guts of one of my amps. This is actually a good example of BAD lead dress (i.e. bad layout, wires criss-crossing, etc.) This happened because I built the amp originally as a Fender-style combo with tubes hanging down. I then rebuilt it as a head with tubes pointing up, ala Marshall. That's why the wires are a mess. http://i134.photobucket.com/albums/q119/Georder/Me016.jpg The finished product atop its cab (w/a Weber 12"): http://i134.photobucket.com/albums/q119/Georder/Me018.jpg For another project, I took a Plexi-style preamp (w/ bright and dark channels) and mated it to a 5w power section. This amp produces gnarly Marshall distortion at volumes that don't need earplugs. It's also great for old-school bass. I gutted my first amp (a SS practice amp) and built the Marshall in there. It cost me $50 and probably would have cost under $100 if I hadn't had any parts. I can email you a schematic if you're interested. http://s134.photobucket.com/albums/q119/Ge.../5w%20marshall/ My final thought... this forum is where I learned tube electronics. People are friendly there (much more friendly than on this forum) and don't mind answering questions that get asked every week/month. http://www.el34world.com/Forum/yabb2/nph-YaBB.pl Edited June 5, 2007 by Geo Quote Link to comment Share on other sites More sharing options...
wwwdotcomdotnet Posted June 5, 2007 Author Report Share Posted June 5, 2007 Geo, you are my hero! thats some motivating info/material! and if you dont mind could i see your schem? ill pm you Quote Link to comment Share on other sites More sharing options...
mikhailgtrski Posted June 5, 2007 Report Share Posted June 5, 2007 i wonder how much i could put that parts list together for if i ordered everything myself individually? I don't think you'd save that much, assuming components of equal quality. The transformers and cabinet are the big $$ items. This DIY cost around $800 in parts that I sourced myself: Quote Link to comment Share on other sites More sharing options...
curtisa Posted June 5, 2007 Report Share Posted June 5, 2007 Here you go. The preamp: A bit of a rats nest in there, but it is completely silent, even under the most brutal gain settings. Essentially it's divided into a few discreet sections - preamp board (plus controls) at the front and left hand side of the case, power supply and transformers at the rear and right hand side, and channel switching at the front-right. I've used shielded wires wherever possible (the big fat grey wires), and heatshrink to cover bare ends where I can (don't want HV wires to break free and short out to anything!) Mine's probably a bit more complex than you were hoping for, but the principles are still the same - Basically you want to keep the electrically "noisy" bits away from the more sensitive sections of the amp. So typically you keep the power supply as far away from the input section of the amp as practicable, use shielded wire where you can, tightly twist any wires carrying high current AC (heater supply for example)... More pics here: http://i153.photobucket.com/albums/s222/ac1176/Preamp3.jpg http://i153.photobucket.com/albums/s222/ac1176/Preamp2.jpg http://i153.photobucket.com/albums/s222/ac1176/Preamp1.jpg And the poweramp: http://i153.photobucket.com/albums/s222/ac1176/Poweramp5.jpg http://i153.photobucket.com/albums/s222/ac1176/Poweramp4.jpg http://i153.photobucket.com/albums/s222/ac1176/Poweramp3.jpg http://i153.photobucket.com/albums/s222/ac1176/Poweramp2.jpg http://i153.photobucket.com/albums/s222/ac1176/Poweramp1.jpg That one's probably even messier and tighter still, but it works perfectly. The same basic principles are being followed aswell from a layout perspective - powersupply as far away from the input as possible, shielded wires, twisted wires etc Also note that the power transformer (front left) and the output transformers (front right) are mounted at 90 degrees to each other (might be a bit hard to see in the pics, but if you look closely the laminations of the power transformer run left-to-right, and the lams of the output transformers run front-to-back) - this is to minimise hum coupling from the power transformer to the output transformers. Most commercial valve amps will do this aswell. Fan-forced cooling probably isn't really necessary for the Marshall 18W. I only use it because I've built something pretty tightly packed into a rack system - it needs all the cooling it can get! Final word of warning - this sort of thing aint cheap! Mikhailgtrski is quite right, the transformers and cabinetry will be quite pricey, certainly the most expensive part of the build. Also, you have to be aware of the dangers of building valve equipment - the plate voltages that they operate at is extremely lethal, let alone the dangers associated with working on something that connects to the mains. Having survived a couple of 240VAC belts in my time I can say you do NOT want to become complacent around this sort of thing - at the very least it will fecking HURT, at the worst it'll kill you. If in doubt unplug it and let it sit for a few minutes before working on it. If you can't see a gap between the power cord and the wall outlet, don't work on it! Quote Link to comment Share on other sites More sharing options...
mikhailgtrski Posted June 6, 2007 Report Share Posted June 6, 2007 Also, you have to be aware of the dangers of building valve equipment - the plate voltages that they operate at is extremely lethal +1 My HIWATT clone carries 450vdc on the plates - gotta be VERY CAREFUL and keep one hand in your pocket at all times when probing around inside a live amp. If in doubt unplug it and let it sit for a few minutes before working on it. The filter capacitors in some amps can hold a very large charge for a long time... you should always check with a voltage meter to make sure the caps are drained BEFORE tinkering! Quote Link to comment Share on other sites More sharing options...
Daniel Sorbera Posted June 6, 2007 Report Share Posted June 6, 2007 ax84.com Great resource for your first tube amp. I built a heavily modified P1 extreme and it turned out great. It's still the amp I use. Quote Link to comment Share on other sites More sharing options...
jnewman Posted June 6, 2007 Report Share Posted June 6, 2007 I've built a few amps, it's good times. You do have to be very careful. I have built a Fender 5E3 tweed deluxe which sounds great and was pretty simple (although the chassis design means it's a little cramped), a modified 18W (the "normal" channel became an EF86-based channel a little like a vox and the "vibrato" channel lost its vibrato and gained the plexi tone stack) which is more complicated and still needs a bit of tweaking with a 'scope but also sounds very good, and a Trainwreck Climax which sounds just fantastic but is also moderately complex. There are literally bunches of companies which offer 18W kits, if you've never built an amp before a kit is a good way to go. A few of the places I know that sell 18W kits are www.ceriatone.com (who I have done business with and have been very happy with), www.gdsamps.com, www.bnamp.com, and www.tedweber.com (some of Ted Weber's kits are modified a fair bit from the original designs). Quote Link to comment Share on other sites More sharing options...
wwwdotcomdotnet Posted June 6, 2007 Author Report Share Posted June 6, 2007 I've built a few amps, it's good times. You do have to be very careful. I have built a Fender 5E3 tweed deluxe which sounds great and was pretty simple (although the chassis design means it's a little cramped), a modified 18W (the "normal" channel became an EF86-based channel a little like a vox and the "vibrato" channel lost its vibrato and gained the plexi tone stack) which is more complicated and still needs a bit of tweaking with a 'scope but also sounds very good, and a Trainwreck Climax which sounds just fantastic but is also moderately complex. There are literally bunches of companies which offer 18W kits, if you've never built an amp before a kit is a good way to go. A few of the places I know that sell 18W kits are www.ceriatone.com (who I have done business with and have been very happy with), www.gdsamps.com, www.bnamp.com, and www.tedweber.com (some of Ted Weber's kits are modified a fair bit from the original designs). jnewman, maybe a kit is a good way to go. I will check into them. Thanks! Quote Link to comment Share on other sites More sharing options...
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