New interstage transformers designed for singleended. Transformers in this category are open frame of various impedance. I took some ohmvoltage measurements with a standard ohm meter while the tranny was totally. As for torstens suggestion to halve the bias current, i think this depends on the current capacity of the interstage transformer. Mouser is an authorized distributor for many signal and audio. Previously only available as very expensive imports from the far east, interstage transformers are believed to be the only true method of driving output. Where z p is the primary winding impedance, z s is the secondary winding impedance, n p n s is the transformers turns ratio, and v p v s is the transformers voltage ratio so for instance, an impedance matching audio transformer that has a turns ratio or voltage ratio of say 2. The excellent magnetic properties of r core and precisely wound coil by the computerized manufacturing system achieve a wide bandwidth, low distortion, and low magnetic loss of the transformer. This version supports the latest interstage version using the. High quality audio transformers sjs electroacoustics. It is no more used a lot, quality transformers are rare and so are their manufacturers.
Full geometric balance for near perfect phase splitting. I took some ohmvoltage measurements with a standard ohm meter while the tranny was totally disconnected. Magnetic coupling in interstage transformer is the best energy transfer mechanism for low frequency audio frequency that can be best viewed same as the force working in most dynamic loudspeaker drivers. The output voltage of a tube stage is much higher than the bias needed for the next stage, we should eliminate the dc and let only the ac arrive to the next stage. The hammond series appears to be a larger transformer. I have numerous times in the past used the pt156 from aes. The right on the photo is the r core audio interstage transformer in bare condition. For model audio interstage transformers for replacement, atwater kent mfg. I also read about the highly regarded amity and karna amplifiers that d olsen built and they have also interstage transformers. Allows you to use your original laminations and housing. Interstage audio transformer too old to reply nelson 20040216 05. The quad split secondary arrangement each secondary section is 12 the turns of. Henney, k radio engineering handbook mcgrawhii book co. I also read about the highly regarded amity and karna.
Most people ive seen tend to comment that the 6s45pe performs ideally at 40ma and above. The best way to drive a single ended or push pull output stages. Also, if you need some more useful information but written in japanese about tamura transformers like how to connect terminals, characteristic figures, etc. If you are looking to replace radiola iiia audio transformers, check out our universal radiola replacement unit. A transformer schematic is depicted in figure 1 below. Perfect drop in replacement for audio interstage transformer for gibson white panel amps that use a transformer for phase inverter.
Based on the 1986 animated movie using the script adaptation by john grant. When conventional design practice is applied to this type of. While the ll1660, ll1692a, and ll1671 have been great transformers in my hands and in those of many others, there was performance to be gained by designing new transformers whose winding geometry has. Much which follows on the topic of audio transformers is of necessity somewhat over simplified to give a general overview. Our part number 124b is the same as our 124a except for 49% nickel laminations for greater fidelity.
Audio transformers signal level, speaker level, tube audio. Tips on audio interstage transformers philco library. Hi all, started digging into this columaire8 and find the primary on the insterstage. Audio transformer and impedance matching transformer. New universal interstage transformer, 20,000 ohm ct primary with 80,000 ohm quad split secondary. The signal has to be low impedant combined with enough current. May 25, 2010 when tested in a radio they performed as an audio interstage transformer and gave results very similar to that of a hammond 124a transformer. The same mounting dimensions as softone rw20, rx405 output transformers, and tango nc20f. I should point out that my main interest is 1920s battery radios and that they are very forgiving. Sakuma says it is easy to build from a reference book or from mj. Transformer audio interstage, 10 ma ce distribution.
If you position a book under the big transformers you can work on the amplifier. Softone rc20 versatile audio interstage transformer. Transformer audio interstage, 10 ma antique electronic. When inquiring about toroid transformers from primrose audio, provide a full. Our range of high quality audio transformers continuous to improve and expand. Transformer, audio interstage, 10 ma equivalent to stancor a53c. Audio interstage transformers antique radio forums. Transformers g1 autobots lightning strike audiobook. Antique radio forums view topic helpinterstage audio. Transformers in this category are hermetically sealed and of higher impedance than 1k ohms. Transformers lightning strike audio cassette by ladybird books childhood throwback, the transformers childrens books by ladybird came with an audio. Interstage transformer question the radioboard forums. This in turn has lead to improvements in tone and musicality, even if measured response has changed little. Designed for general purpose or replacement use in single ended or phase inverter tube driver circuits.
There are many ways in connecting a driver to a powertube, all with the same goal. The quad split secondary arrangement each secondary section is 12 the turns of the whole primary means that as many as 4 tubes can be driven, each independently biased if wired for 1. When conventional design practice is applied to this type of transformers you easily get destructive capacitive coupling between the primary and secondary windings. Extensive range of performance audio transformers shipped worldwide delivery updated 6th april 2020 please look below for the latest situation. I was told by one tech the most influential transformer in a piece of gear is the input transformer. During the last year lundahl transformers have developed a new line of singleend to singleend 1.
If necessary, you could use a pptose interstage transformer, and a rheostat to find the appropriate flux density. Merren audio provides custom wound transformers for both output and power applications including chokes. Original transformer primary went open after about a month when restored set started being used 23. I notice lots of old tube gear like pultec eqs, universal audio 175s have interstage transformers. I replicated the circuit faithfully with an exception of the interstage transformers. Primrose audio toroid power transformers for audio builders. Jan 22, 2010 this may be critical on hi fi audio transformers but these old 1920s sets seem to be forgiving as noticed by the many different transformers that have been used sucessfully as replacements.
High performance transformers for coupling between valves tubes. Impedancein audio transformers even mixing consoles especially in recording work, but also in many live sound applications all depend on transformers to match the high impedances of. Hammond 124 series tube driverinterstage transformers, designed for general purpose or replacement use in pushpull or phase inverter tube driver circuits. This is a universal replacement type it will replace any of the. I have used several in various radios with success.
A low current wallwart xfmrs can also do the trick. Used it to replace a driver transformer for pp 45s in a gm253 lowboy ca. Transformer audio interstage, 10 ma equivalent to stancor a53c. Connect the grnyel wire to the grn wire and the blkyel wire to the blk wire. High performance interstage transformers for pushpull and single ended drive. Hammond manufactures direct replacement transformers for popular tube amps from fender, marshall, vox, ampeg, orange, and yorkville traynor. Just had to play with the capacitor value to get the bass response back to original. Although interstage transformers were considered no good for sound, the amplifier now. Wide bandwidth output transformers for single ended and pushpull vacuum. Output transformers can be designed and built with linear taps. Center tapped secondary may be used for pushpull grids. I believe the tranny is a audio interstage transformer but not sure that is the proper name. The original transformers are usually found with open windings due to the fine wire and high turns usedcoupled with age.
When inquiring about toroid transformers from primrose audio, provide a full address with postal code, and we will quote not only on your transformer requirements, but also provide postal costs to ship to your address. They have a 100v rating but many sets only run 90 volts anyway. Home the canadian vintage radio society, and its bimonthly publication, canadian vintage radios, is dedicated to the preservation, restoration, collection and. Audio interstage transformers are hard to get now, and this is a good source. Problem when i had this problem, robert casey suggested the capacitor fix. Its important to remember that when theyre talking about audio interstage transformers, and refer to 3. Hammond puts a century of experience into manufacturing high quality magnetics for tube applications like hifi audio and guitar amplifiers. Over the past years we have spent an increasing amount of time fine tuning the materials and winding techniques employed in constructing our transformers. Silver wire windings available at current market prices. Interstage transformers can be made in different ratios, primary currents and voltage ratings. Satellite tv equipment free delivery possible on eligible purchases.
Somehow, it looks like some of the most expensive set amplifiers have interstage transformers like audio note or shindo. Discover delightful childrens books with prime book box, a subscription that. This is a universal replacement type it will replace any of the three audio transformers used 1st audio driver2nd audio phase splitter stage or output transformerby correctly connectiong the 5 lugs. At this point, if you find the word audio transformers on its left side, please click on the word or on a small picture on the other side to see the catalog 392k in pdf file. Audio interstage transformers for radio part atwater kent mf. Over a period of several months while doing development work on audio amplifiers, the. About us the canadian vintage radio society is dedicated to the preservation, restoration, collection and enjoyment of antique radios and related items. Transformer audio interstage, 10 ma antique electronic supply. New tube gear mostly only have an input and output transformer. Impedancein audio transformers even mixing consoles especially in recording work, but also in many live sound applications all depend on transformers to match the high impedances of the tubes to useful interstage and output impedances. If youre antsy about that voltage you can always put this one on the detector and move a good detector one to the first audio.
Audio transformers were originally used in valve or tube amplifiers as interstage and output transformers. Audio interstage transformers from scrap canadian vintage. Antique radio forums view topic audio interstage transformers. The product is enclosed in the square case on the left. Pages in category audiobooks the following 28 pages are in this category, out of 28 total. Magnetic coupling in interstage transformer is the best energy transfer mechanism for low frequency audio frequency that can be best viewed same as the force working in most. If youre antsy about that voltage you can always put this one on the detector and move a good. Tube amplifiers and interstage transformers audiogon.
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