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Adam P wrote: Sat Apr 02, 2022 10:45 am

Dr Tony Balls wrote: Sat Apr 02, 2022 9:55 am

Adam P wrote: Sat Apr 02, 2022 9:46 am Was going to say, the abundance of small & useful power amp options kind of makes designing a power amp unnecessary. I’d say focusing on preamps would be a better idea, but there’s also plenty of clones of most of the desirable vintage stuff at this point as well.

Even if I was building a thing, I wouldnt really "design" a power amp, i'd just copy a decent example from Peavey or Traynor or whatever.

Sure. Design, copy…I guess my point is that solid state power amps are pretty much linear clean gain, and there’s plenty of stuff out there already that does it perfectly fine.

What about something like a preamp with an onboard power amp using something like an STA540 (like the Orange Micro Terror) and a line out for driving other amps?

TonyAsh wrote: Sat Apr 09, 2022 9:17 am Just scrolled through 10 full pages to confirm that nobody (myself included) had sung the praises of the Vox Pathfinder 15 yet. Up until about three years ago you could get these for under $100 all day, though they have been climbing well into $200+ territory lately. They really do the tube Vox AC thing super well, especially when plugged into a good 2x12 or 4x12 cabinet. In my opinion, the way to get the most out of these is to engage the often maligned Boost button, but run the Gain control fairly low. It really fills things out. Plug in a Les Paul and play "Search and Destroy." It sounds perfect.

Give me one of these (or a Marshall Lead 20 as I mentioned before) over a Champ any day. Hey speaking of which, I'm selling a 5F1 tweed Champ clone. The Marshall and Vox solid state combos see all of the at home playing time now.

Adam_I_III wrote: Sun Apr 10, 2022 5:23 am or HH is perhaps too easily dismissed due to ubiquity

bishopdante wrote: Sun Apr 17, 2022 3:12 am Peavey PV1200 power amp + preamp of your choice into a normal 4x12 marshall greenback type guitar cab.

I'll mark it down some for the lack of XLR balanced line inputs, but this thing is ideally loud - where you thought a 50W or 100W amp might do the job, this thing does the same job without clipping the transients to the same extent.

You might think 600W per channel or bridging it to 1200W would fry speakers, but it doesn't. It's power amps clipping to square that destroys speakers, not a brief peak, and the thermal limit for a loudspeaker is roughly estimated to be continuous white noise, so if you listen to music, you can use a "music power" estimate for your amplifier's peak capacity. The bad news about this is that you'll use very, very expensive amplifiers to power relatively underpowered speakers – you can plug that lab gruppen 25kW amp into those 10W full-range horn loudspeakers, and that isn't "audiophile cork sniffing", that's just no clipping and no dynamic compression, and will provide a genuinely linear response. Handling huge peaks briefly is something most power amplifier designers haven't considered, and very few people run their systems set up that way. I don't think you can buy a commercial record which has no compression on it at all.

When acoustic music is recorded without dynamic range compression or limiting, the signal contains brief peaks of much higher amplitude – 20 dB or more – than the mean. Since power is proportional to the square of signal voltage, their reproduction would require an amplifier capable of providing brief peaks of power around a hundred times greater than the average level. Thus, ideally a 100-watt rated loudspeaker would need to be driven by an amplifier capable of handling brief peaks of 10,000 watts in order to avoid clipping. You can use a lot more amplifier power than you think, and so long as there's no clipping to square, or lots of high frequency content, you won't set that speaker on fire.

In fact, I have come to the conclusion that the wattage ratings printed on speakers and amplifiers are basically worthless as a predictor of whether you'll blow it up. This amplifier seems to be really immune to destroying speakers, whereas I have 100W solid state amps that can and will kill the drivers. It's those evil square waves. It's all true, folks. Use the highest rated amplifier you can find, it'll be fine (within reason [depending on program material {get a clean sounding analogue limiter and set it to restrict the level long before the amp goes into clipping} ]).

bishopdante wrote: Sun Apr 17, 2022 7:33 pm
You might think too much amp power is a bad idea, but it's surprisingly not a problem unless you use a lot of square waves, or drive the amp into clipping.

bishopdante wrote: Sun Apr 17, 2022 8:37 pm

TylerDeadPine wrote: Sun Apr 17, 2022 7:52 pmno-one needs to destroy some greenbacks, they can use other speakers with higher power handling if they want to run a high powered solid state amp and enjoy all the benefits of both.

Why don't modern PA speakers come with a built in thermocouple, so that you can thermally monitor them and know when they're getting too hot? Could even have it spray the magnet with a "quench" coolant in meltdown conditions.

TylerDeadPine wrote: Sun Apr 17, 2022 10:17 pmI like this quench coolant idea. Basically any time someone can be slimed a-la You-Can't-Do-That-On-Television is good in my books.