stereo powe amp

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AC Cobra
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stereo powe amp

Post by AC Cobra »

Hi, Im new here, but can tell there is a lot of knowledge here. Im thinking about building my first amp. I am currently running 2 half stacks in stereo with the second amp slaved throuh the effects loop. As you could guess it is too loud (I no longer play in a band and just play at home). I tried a hughes and kettner 18w amp and it seemed to do what i wanted, although i would prefer power scaling/VVR to the power soak and i would need 2 to do what i want.
I was thinking a better option would be to build a amp with 2 18watt powersections, with a effects return goint to each one. I could slave this power section off one of my existing amps and build/modify a couple diffrent preamps, and then put it all into a full size head when i am happy with the preamp combo.
I was concidering using heybore or classic tone transformers (im glad i didnt like the sound of the MM's as much in the comparison i listened to as the cost of 2 of those would be huge). I alsothouht it might be good to use 6V6's on one of the amps and run one to a open back speeker, and the other to a closed back. I was hoping that the 6v6's would still be clean when the el84's are starting to break up. Also expecti g a larger tone diffrence with the diffrent power tubes/speeker cabs. I heard positive reviews of using 2 6v6 and 2 el32's, but this would be mixing the sound in the air waves, not in the amp so it may not be the same.
I dont know alot about effects loops other than most people here seem to think these amps shouldn't have them, but a good seriese effects loop will be necessary for what i want to build.
Any advice/recomendations would be appreciated.
Thanks
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zaphod_phil
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Re: stereo powe amp

Post by zaphod_phil »

Yes, just build a regular 18W which already has published schematics and layout, and can be supported by the community. You will enjoy it hugely. Avoid building any off-the-beaten-path Frankenamps until you've got a few successful builds under your belt. :)
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Nature abhors a clean tube amp

AC Cobra
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Re: stereo powe amp

Post by AC Cobra »

That sounds like good advice, cut my teeth on something i can get help with when things go wrong. Couple questions on what direction to go. It seems power scaling is prety common, and is also the #1 feature i would want (the stereo power section would be #2). Would it be reasonable to build a amp with power scaling for my first build? My brother is a electrical engineer, and has experence with that type of circuit already, and although he has no experence with tubes, would be intrested in buolding the amp with me.
Would it be reasonable to modify the amp AFTER it is working properly by adding a effects loop? Seems that would be easier than building a second amp. If that works i could then build a second power section. I will build my own chassis and head, so i could leave room for future mods if that is what i plan on doind down the road. If it is better to just build a second amp, i would make it smaller, but i would still build the chassis as i have access to cnc equipment. I ould also want a power transformer with a higher current rating if im concidering modifying the amp later.
Dose anyone have a oppinion on the classic tone transformers?
Thanks
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CurtissRobin
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Re: stereo powe amp

Post by CurtissRobin »

My advice is to scale back your wants and wishes. Yes, you could build something with allowance for all kinds of mods and upgrades and features but for a first build I STRONGLY recommend doing something relatively simple, in its unmodified, original form. Having built no tube amps before, you have no idea how rapidly the difficulty and confusion ramp up when you "enhance" a circuit before you're familiar with amp building. A successful first build lays the groundwork of skill and experience you need for getting more elaborate with your second.

It's far more satisfying to build a simple, unmodded amp that works well than to build one with all the features you want that devours all your free time with debugging and tweaking.

JMHO
KennyO
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AC Cobra
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Re: stereo powe amp

Post by AC Cobra »

I am prety ambitious, and i know what I want, but I think it will be best to put what I want on the back burner untill I have built a proven amp. Maby leave it on the wish list even longer than 1 amp, ill worry about that later.

For my first amp would a lite IIb with vvr be realistic? Or should i just do a lite without vvr? I do have a schematic for that amp, and it seems the vvr is common enough here, but would i be better off forgetting about that as well on my first build?

Thanks again.
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CurtissRobin
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Re: stereo powe amp

Post by CurtissRobin »

The Lite IIb is a single channel version of the 18 watt amp. There are a couple kits out there. I like the GDS S/C a lot. all Graydon's parts are high quality and his transformers are among the best. The VVR is a pretty easy change to the power supply circuit and a good choice for a first modification after building the amp. I have no doubt you'll love the finished product.

KennyO
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