Re: what's everyone building these days?


"Bret Ludwig" <bretldwig@xxxxxxxxx> wrote in message <snipped some>

: > When I see a transient involving a peak signal power of 3,000 watts,
: > I will eat the amp and speaker. This is 219Vpk into 8 ohms.
:
: Better bring a power hacksaw and a lot of time. Mc proved in the 80s
: that a CD played in a typical room through typical speakers could
: require peaks of 3500 watts based on the limits of dynamic range of
: the CD.

..................
let's see. 3 W average, 3500 W peaks, that's over a 1000 to 1 or
30 dB range ... no recorded music has such a high crest factor
(the track Indigo, recorded live, Clarke/DiMeola/Ponty, has an
84 dB dynamic range & 22 dB crest, pretty impressive:)

so it must be wrong on *that* account.

at 2% acoustical efficiency, 7 KW translates to bloody dangerous
acoustical energy & SPL's, mate !

Rudy


At that time they were interested in selling their Power Guard
: system, which was patented. But they were right. Power Guard patents
: have run out (and in any event, a former Mc engineer, Milojub
: Nestorovic, designed a noninfringing and better version which went
: into the cheap TAPCO products) so now they promote a 1 kW monobloc.
: >
: > Peaks of 300 watts are also somewhat impossible for most amplifiers used
: > by most ppl
: > of say 30 watt capability because you need
: > a peak V swing of 68.6V into 8 ohms.
: > People I know NEVER use the available headroom of a 300W amp
: > unless they are just out to impress their mates about the power, and
: > don't mind
: > damaging everyone's hearing.
: >
: > > Now if they actually get 3 kW at those peaks something has to give,
: > > the drivers usually. Tube amps do give a softer clip.
: >
: > Wrong. Even a triode amp without any GNFB will clip sharply.
: > Amps of any kind with NFB will clip hard, unless they are designed to
: > compress,
: > but even that generates an appalling hash of harmonics....
: >
: >
: >
: > > Now if you are talking large Klipsch or Altec or more modern horns
: > > then yes much less power is needed. But the idea that five milliwatts
: > > is adequate is not the high fidelity concept at all.
: >
: > Huh? say you have an 8 ohm horn good for 105dB/W/M.
: >
: > For 85dB, you only need 1/100 of a watt, or 10 miliwatts.
: >
: > For a violin solo, 5 milliwatts is enough.
: >
: > The THD/IMD of any SET amp reduces with output towards zero and is of no
: > concern at such
: > low power levels all below 0.1 watts most days.
: >
: >
: >
: > > By using a big enough tube (except for Klipschhorns, the 211 is about
: > > the smallest worth bothering with) and some feedback, something
: > > approaching satisfactory results can be had. But....a pair of most any
: > > receiving tubes in push pull beats the 211/845 single ended and costs
: > > and weighs less.
: >
: > Ain't necessarily so.
: >
: >
: >
: > > I have listened to any number of 300B, 2A3, and other SE amps. Maybe
: > > for a bedroom set they would be satisfactory but even on Klipschhorns
: > > they run out of steam.
: >
: > You really need to see an audiologist to have yourself fitted with a
: > hearing aid.
: >
: > > Most are so dreadful that you can hear them
: > > slobbering all over even moderately loud passages. I heard one of the
: > > Jolida PSE amps on expensive Wilson Audio speakers at a local high end
: > > whorehouse. It was so bad that even one of the local yuppies
: > > commented, Gee, it sounds a little funny.
: >
: > Probably a very poor example of badly done demonstration.
: > Last time I filled a big room with 2 x 25 watt SE amps the 30 ppl
: > present
: > were all smiles and couldn't get enough.
:
: 25 watts is a lot more than those jolidas were good for. I'd guess a
: real rating would have been 4 watts for them. I offered to bring in a
: borrowed AP Portable One to test the unit but they refused. In fact
: that store will not extend the courtesy to me to borrow units over the
: weekend (with a deposit of course) they do to most everyone else
: because they are convinced I'll test them and nark on them how raggy
: they are.
: >
: > > snip,,,
: > > > That all depends on levels and thresholds and how much ceiling and power
: > > > you have.
: > > > Using SET amps does not automatically wreck music every time.
: > > > Hence many people using SET amps know their amps present the music
: > > > as it IS supposed to sound.
: > > > One guy I know has Tannoy Gold Monitor speakers in 6cu.ft.cabs.
: > > > And 9watt SET amps. It is a heavenly system for music of any kind....
: >
: > > Well, if you listen quietly enough, I suppose.
: >
: > What may seem quiet to you may seem loud to other folks.
: >
: > I know this. I once re-wired a pair of 1960 EL34 PP monblocs for a
: > musician rock'n'roll guy
: > who foolishly expected they'd outperform a 100 watt amp
: > and at the demo when I'd finished the work. I had fingers in my ears and
: > he
: > shouts at me, "they don't go very loud do they!!!"
: > He was serious, and refused to pay for the work he'd implored me to do.
: > So I sold the amps to someone with better hearing.
: >
: > Too much loud music is bad for you.
: >
: >
: >
: >
: >
: > > A 300B SE in a biamp arrangement can do OK for the treble, but very
: > > few people can set a biamp setup up properly. They pay lip service and
: > > then listen to the SE full range, slobbering all the way.
: >
: > > > > The 300B in push pull can give good results but it's expensive and
: > > > > inconvenient. The original WE tubes were exceptionally long lived, but
: > > > > ONLY when operated at very conservative plate ratings and not cycled
: > > > > very much. In normal audio service, they last no longer than any old
: > > > > consumer tube.
: >
: > > > Wait a minute, 300Bs were used in theatre amps LEASED out to the
: > > > theatres for a
: > > > fee. WE made sure they were reliable and long lived because they had to
: > > > earn their keep.
: > > > Theatre amps copped huge "cycling", and were often run 3 hours a night 6
: > > > days a week,
: > > > and MORE than use by many audiophiles.
: >
: > > No, they left them on all day or permanently.
: >
: > Either way thy copped a lot of work.
: >
: >
: >
: >
: >
: > > > They were used in telco service 24/7/365, and in cinema
: >
: > > > > serviced they were changed out pre-emptively. Bags of used ones were
: > > > > common at hamfests until the Ollies started buying.
: >
: > > > Your'e right though about output tubes in general; if used
: > > > conservatively
: > > > and without allowing leaky coupling caps to destroy them, output tubes
: > > > of all sorts
: > > > last a long time and perhaps as well as the WE 300B. Transformer
: > > > coupling
: > > > ensured grids remained at the bias voltage!
: >
: > > The ERPI techs came with the lease and they changed the tubes
: > > regularly. The amps ran all day, either 24 hours or one cycle a day.
: > > The used ones were retained for spares and rotated out, excess ones
: > > were supposed to be destroyed. In those days they were valuable as any
: > > tube was that worked at all during the depression and WWII. If the
: > > amps didn't work you had a revenue issue. The lease was quite
: > > expensive but they guaranteed near 100% uptime.
: >
: > > WE didn't use their own tubes for strictly technical reasons. There
: > > was a licensing issue as well. There were dozens of patents covering
: > > tube making and amplifier circuits and WE joined the "pool" of
: > > manufacturers for patent cross-licensing, which was established for
: > > everyone's benefit. WE made tubes first and foremost for telco use and
: > > they had to be highly reliable and long lived vis-a-vis commodity
: > > tubes. In order to get full use of the licenses there was a quid pro
: > > quo and products were licensed for sale for specific uses. In WE's
: > > case consumer use was not one. WE tubes were not supposed to be sold
: > > to consumers, and the license on regular tubes covered consumer and
: > > many commercial uses, but not cinema sound or telecom. After WWII the
: > > matter became less important and no one cared anymore, but it was
: > > tough to get WE tubes throughout their manufacture for noncommercial
: > > users.
: >
: > Thank goodness such restrictive trade practices have been binned.
:
:
: Well, they weren't banned per se. WE spun off the audio business as
: Altec, the patents started running out, and most significantly, in the
: US, the vertical film business-studios owning the cinemas-was held as
: a conflict of antitrust law. That meant the end of the Studio System,
: and the development of talent that accompanied it. When ERPI was stood
: down, they would go around and sledge the amps at lease end if it was
: convenient for them to do so (so as to promote Altec sales) and sell
: them out to the cinema owner for $1 if it wasn't (and they weren't
: particular about actually collecting the $1.) They were huge, low
: power and old so owners junked them usually. The ollies started
: quietly buying them in the late 70s and it wasn't until the late 80s
: anyone over here realized they were bringing real money over there.
:
: You could buy WE tubes through Graybar from the late 40s onward and a
: few people did buy them for hi-fi. See the Audio Anthology Vol. 1
: which you should have. They were expensive but not freakishly so.
: Besides a couple of surplus things hams used, 300Bs were used in some
: versions of the Brook amplifier (they were made to be wireable for
: 2A3s or 300Bs) and in some homebrews and modified sets. There was a
: mod for the E.H. Scott Philharmonics and Quaranta that changed out the
: output tubes for 300Bs along with the output transformer for a UTC and
: added negative feedback. It was sort of popular, as Scott collectors
: bitch that they run into them occasionally.
:


.

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