Does anyone care to ask an amplifier designer a technical question? My door is open.

Speaking of Maggies... I would like use a quality, lower powered tube amplifier to drive mine. What is your idea of an appropriate amount of “tube” power for them? I sit about 9 1/2 feet from the speakers in a 14’ x 21’ x 8’ room, and typically listen at 80-85 dB (measured with a RS meter; C weighting/slow response). They’re rated for 86 dB/ 2.83v/ 500 hz. My preamp volume control is almost always around to 9:00. I really appreciate the idea of simple circuit design for both the amplifier and the preamp. I just feel like I’m not using the power in my amp (200w/ch), and also that I’m not using the gain in my preamp (12 dB). Power is expensive, and I’d rather put the money into the quality of the amp if I don’t “need” the hundreds of watts. 

@fsonicsmith

you can’t possibly mean that preamps are easier in general and I am unaware of any accolades for your preamps (whereas you are lauded for your amps). Obviously you mean that for your tastes and purposes, preamps are easier than amps.

I mean precisely that. You might want to do a little more reading on the RM-1 and RM-5. Perhaps you are new to this hobby.

This has nothing to do with my tastes and purposes. The RM-1 (1976) was lauded for its RIAA EQ accuracy, was the first popular preamp to use the 6DJ8/6922, has the lowest noise possible for that tube. Has 5 fully regulated, short circuit proof power supplies. Built in two chassis and weighs 55 pounds ! It is the only tube preamp to my knowledge that id DC coupled throughout with servos, relay protection and no output coupling capacitor.

That was a lot of work, But once you make a good preamp what is there left to do?

Power amps, on the other hand are a world of variety. Circuit topoligies, output transformers, protection, tube life. These are really difficult things to do.

Granted most people who dont design preamps will agree with you, but they dont design preamps, now do they?

A great preamp does more than attenuate a signal. It breathes life into music. A great preamp is quietly powerful, while a great amp simply provides grunt.

A preamp does not attenuate a signal, it amplifiers a signal, provides selection of sources and control of volume, accurate phono EQ. But these are easy to obtain. There are only about 3 ways to make a preamp gain stage. There are an unlimited distinct ways of making a power amp and a good one is a challenge.

I will say that many preamps fail because of poor power supplies. My power supplies are among the finest and they dont break like ARC power supplies. You can short my power supply, go to lunch, come back, remove the short and all is well, doesn’t even get hot. One millisecond short on an ARC power supply and you wont have time for lunch or dinner. Ask any tech.

A power amp is the finess in a system, certainly not the grunt.

May I remind you this is a thread to ask a technical question.

using a few of your own words, perhaps you did veer into “ tall poppy “ turf a bit...

in my inteactions w very talented engineers over the years - and there have been many , many outside of audio, ego is also an essential design ingredient... there are some speaker people doing a bit more than just buying off the shelf cones...some of them make amplifiers..

” I was about to write that the M7-HPA measures well for an amplifier with zero loop-negative feedback. Actually it measures well period. John Atkinson.....

I think he liked how it sounded also with cone speakers ;-) I think there are several paths the enlightenment....

I see I veered away myself...

a ? ( repeated ) have you measured the 240 ?

and on the RM-10 can you talk about 35 WPC vs the class A 25 wpc version w hand wound transformers?

I think either one could drive my 85 DB, 6 Ohm (+/- 3 ) speakers. Loud is 90 db C weighting, slow on the venerable R-Shack analog
most of my listening is done low 80’s....

current amp is a NAIM SS class A/B solod state...it has plenty of grunt.....

ramtubes

Was the preamp you mention above marketed by Beveridge Audio, I searched it and the only preamp that came up was RM1 and RM2 by Beveridge.  I'd be very interested in getting one of them.

Thanks

Peter
PBN Audio