Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: hesamadman on December 16, 2015, 09:51:50 am
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Ive been wanting to build a high gain amp for some time now. Ive only researched a little but I've come up with the model from weber. I am having a rough time following amp schematics with relays and switching. I was hoping to get some help figuring this out. I would like to build just a single channel version of something like this and maybe down the road try a two channel and learn switching from there.
Maybe if anyone had time, possibly trace the signal flow of the hi gain channel?
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> if anyone had time, possibly trace
If you are going to build it, maybe _you_ should find the time....?
> rough time following amp schematics with relays
Yes. First use a crayon to mark the relay flappers in the mode you wish to trace; it is too mind-bending to trace always remembering which-way at every relay unless you mark-up the intended mode. Also, when a relay is drawn way out of place, copy-paste it (or a near-scribble) to the more logical place. Here, half the top-left relay "should" go toward the middle, where its three contacts 1C 1NC 1NO happen to be near each other. (Sometimes they don't fall together and you should just crayon the functional connections.)
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That amp is SLO100 so if you want a single channel version you could try this:
http://el34world.com/charts/Schematics/files/soldano/soldano_super_lead%20_60.pdf (http://el34world.com/charts/Schematics/files/soldano/soldano_super_lead%20_60.pdf)
or one channel from this:
http://el34world.com/charts/Schematics/files/soldano/soldano_x88r.pdf (http://el34world.com/charts/Schematics/files/soldano/soldano_x88r.pdf)
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... and here is a great info on slo100 preamp:
https://ampbooks.com/mobile/classic-circuits/soldano-slo-preamp-1/ (https://ampbooks.com/mobile/classic-circuits/soldano-slo-preamp-1/)
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Here's a much easier to follow schematic. It has a 5 gain stage preamp. No fancy switching. It's coupled to an 18W power amp but you could connect it to the power amp of your choice. I have more info on this project if you are interested.
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AX84 provide excellent documentation for a variety of projects. You could combine the LEAD PREAMP (http://ax84.com/static/corepreamps/Lead/AX84_Lead_Preamp_Schematic.pdf) with any of the power amps and get a good result.
The Single Ended Lead (http://ax84.com/static/sel/AX84_SEL_101004.pdf) is a complete amp, schematic and layout.
Hope that helps,
Chip
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Thank you everyone for your help. This is EXTREMELY helpful. I have multiple goals here. One is to understand these relays and channel switching on schematics. PRR's explanation was perfect and I am currently studying this.
My other goal is to try and build a higher gain amplifier than the 2204. Using more tube gain stages rather than adding gain to the 2204 circuit. When I will get around to this I have no idea, but right now is research stage. :icon_biggrin:
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Take a look at this. It's the Soldano Hot Rod 50 single channel. Based on the SLO preamp, they have many more similarities than differences. No LDR's or relays to make things complicated. More gain than a 2204 but not ridiculously so and it's smoother because the gain is spread out over more stages without any one stage being really over gained. I own one of these and I love it. One important note: the effects loop as designed is set up with levels suitable for use with rack gear. Most folks don't use the effects loop. Pedals sound great in the front end. I think it would be important to leave the two effects loop tube stages in place since they do provide some gain and tone shaping. There are plenty of stages for tweaking to get the gain just where you want it. Ignore the XL mod - it's a resonance/depth circuit set at a preset level. The adjustable depth control is great. I honestly think this is the best amp Soldano ever made.
http://www.nicosonic.com/sites/default/files/pics/Soldano%20HR50%20SL60%20+%20XL%20mod.jpg (http://www.nicosonic.com/sites/default/files/pics/Soldano%20HR50%20SL60%20+%20XL%20mod.jpg)
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I went looking for more info on Sluckey's proffered design and ended up on the Marshall Forum studying the particulars of the associated Mojo... Anyway, one of the links led me to a Youtube series called Amp Fest, found here: https://www.youtube.com/watch?v=59JJX6p3XQM (https://www.youtube.com/watch?v=59JJX6p3XQM) .
There are 3 in the main series and then videos of the recording setup used for each amp are found in their own series. (If your speakers sound like they are blowing in the recording setup series your viewing the right ones. At 10 ft the mics are still being overdriven). While I haven't had a chance to listen to all the amps in the mix, what I've heard so far gives a really good review of some premier High Gain Amps played through by some great players. You may want to take a listen for ideas on where to start. Something that struck me was how all the specimens in the test sounded very much alike with only a few notable exceptions. To my ears they all sounded "Killa" and one could hardly go wrong choosing any of the designs as a starting point.
A question I have is whether or not these amp reviews deserve their own post in a separate section as a sort of design guide?
silverfox.