One thing that we need to have clear here. In the days that these speaker units were made, the output impedance of the rtadio was in the order 1000-2000Ohms. That was the general impedance of headphones, horn speakers and the early magnetic cone speakers. What they did was couple the output tube to the phones or speaker. This device that we're talking about is rerally a horn speaker without the horn.Your Victrola furnished the missing horn. Victor did this on several models of orthophonic Victrola-Radiola combinations.
The other thing to remember is that the output power of those old 3-dialers was probably not a whole watt. The output power of a modern transistor radio, especially a large one is higher than one of the old battery sets! Now, back to the topic of impedance. The headphones we use today ar low impedance devices, so the voltage output of your stereo or transistor set is far lower than on the mid-twenties set. If you're confused, lemme make it worse. High impedance means (in this case) high voltage, low current in the speaker. Low impedance means low voltage, high current. So, in order to match the old speakers to modern outputs, you can use an output transformer whose secondary impedance is low (4-8 Ohms) and whose primary impedance is 2000 Ohms or so (It isn't critical). You simply connect the low impedance side to the transistor set, and the high impedance side to the horn speaker, and it will work very well. In this, you're just hooking the transformer in reverse, to match the spaeker to your signal source. Since probably the fifties or so, the Hi-Fi headphones are really little speakers that are mounted in the ear pads, so that's why they are low impedance units; they're just speakers. Oh, and the other thing....don't push the old speaker units too hard. They were never made to handle much output, and a modern stereo amplifier could blow them out pretty quickly. remember that the 3-dialers put out less than a watt, and some of these stereo sets could vaporize the coils in the litle ole horn speakers. (My Fisher 800C puts out something like 35 wayys per channel). If you're confused, my day has been worth while! ----- Original Message ----- From: "Ron L'Herault" <[email protected]> To: "'Antique Phonograph List'" <[email protected]> Sent: Tuesday, July 05, 2005 4:51 PM Subject: Re: [Phono-L] Unusual item on eBay > Does that mean that you couldn't use the headphone jack of a portable > player? Too bad, because that could be secreted under the closed lid of > the > machine. Could you use any other normal Audio output? > > Ron L > > -----Original Message----- > From: [email protected] [mailto:[email protected]] > On > Behalf Of Dan Kj > Sent: Tuesday, July 05, 2005 4:03 PM > To: Antique Phonograph List > Subject: Re: [Phono-L] Unusual item on eBay > > They usually had an internal resistance of between 2,000 and 4,000 ohms, > for > > connection to something like a Radiola 18 > > > ----- Original Message ----- > From: "Ron L'Herault" <[email protected]> > To: "'Antique Phonograph List'" <[email protected]> > Sent: Tuesday, July 05, 2005 3:58 PM > Subject: Re: [Phono-L] Unusual item on eBay > > >> It might be interesting, if it works, to parallel outputs from a portable >> CD >> or MP3 player and pump them through an Orthophonic horn with this thing. >> Thinking Al was interested, I didn't go back and bid on it. >> >> Ron L >> >> -----Original Message----- >> From: [email protected] [mailto:[email protected]] >> On >> Behalf Of Dan Kj >> Sent: Tuesday, July 05, 2005 1:45 PM >> To: Antique Phonograph List >> Subject: Re: [Phono-L] Unusual item on eBay >> >> I'll find out about the windings, when it gets here (I bought it; for >> $10, >> what the heck) ... I do have a driver made to fit on the Edison diamond >> disc machine, and it still works fine - but was also still in its box & >> might not have been used in the past. >> >> >> ----- Original Message ----- >> From: <[email protected]> >> To: <[email protected]> >> Sent: Tuesday, July 05, 2005 12:30 AM >> Subject: Re: [Phono-L] Unusual item on eBay >> >> >>> >>> In a message dated 7/4/2005 1:45:17 P.M. Mountain Daylight Time, >>> [email protected] writes: >>> >>> This doo-hicky is a speaker driver that is intended to go in place of >>> the >>> sound box on a phonograph. It uses the horn of the phonograph as the >>> necessary horn for its operation. There were several such attachmernts >>> for >>> phonographs in the days of battery radios. It's reasonable to expect >>> that >>> the winding in these speaker attachments are open, and that the thing >>> wouldn't work, but....... > > _______________________________________________ > Phono-L mailing list > [email protected] > > Phono-L Archive > http://www.oldcrank.org/pipermail/phono-l/ > > > > _______________________________________________ > Phono-L mailing list > [email protected] > > Phono-L Archive > http://www.oldcrank.org/pipermail/phono-l/ >
