Primrose audio toroid power transformers for audio builders. Hammond puts a century of experience into manufacturing high quality magnetics for tube applications like hifi audio and guitar amplifiers. The quad split secondary arrangement each secondary section is 12 the turns of. High performance transformers for coupling between valves tubes. This version supports the latest interstage version using the.
The best way to drive a single ended or push pull output stages. Interstage transformers can be made in different ratios, primary currents and voltage ratings. The product is enclosed in the square case on the left. Center tapped secondary may be used for pushpull grids. Problem when i had this problem, robert casey suggested the capacitor fix. A transformer schematic is depicted in figure 1 below. I should point out that my main interest is 1920s battery radios and that they are very forgiving. Mouser is an authorized distributor for many signal and audio. 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. High performance interstage transformers for pushpull and single ended drive. 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 you position a book under the big transformers you can work on the amplifier. I took some ohmvoltage measurements with a standard ohm meter while the tranny was totally disconnected. I also read about the highly regarded amity and karna amplifiers that d olsen built and they have also interstage transformers.
Softone rc20 versatile audio interstage transformer. Although interstage transformers were considered no good for sound, the amplifier now. There are many ways in connecting a driver to a powertube, all with the same goal. The same mounting dimensions as softone rw20, rx405 output transformers, and tango nc20f. During the last year lundahl transformers have developed a new line of singleend to singleend 1. Our part number 124b is the same as our 124a except for 49% nickel laminations for greater fidelity. New tube gear mostly only have an input and output transformer. I was told by one tech the most influential transformer in a piece of gear is the input transformer. 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. I also read about the highly regarded amity and karna. Transformer audio interstage, 10 ma antique electronic supply. If necessary, you could use a pptose interstage transformer, and a rheostat to find the appropriate flux density. Transformers in this category are open frame of various impedance.
When conventional design practice is applied to this type of. Output transformers can be designed and built with linear taps. New interstage transformers designed for singleended. Over a period of several months while doing development work on audio amplifiers, the. Transformer, audio interstage, 10 ma equivalent to stancor a53c. Pages in category audiobooks the following 28 pages are in this category, out of 28 total. A low current wallwart xfmrs can also do the trick. Silver wire windings available at current market prices. Transformer audio interstage, 10 ma equivalent to stancor a53c. I have used several in various radios with success. Over the past years we have spent an increasing amount of time fine tuning the materials and winding techniques employed in constructing our transformers. The right on the photo is the r core audio interstage transformer in bare condition. Tips on audio interstage transformers philco library. Based on the 1986 animated movie using the script adaptation by john grant.
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. Transformers g1 autobots lightning strike audiobook. As for torstens suggestion to halve the bias current, i think this depends on the current capacity of the interstage transformer. Hammond manufactures direct replacement transformers for popular tube amps from fender, marshall, vox, ampeg, orange, and yorkville traynor. The signal has to be low impedant combined with enough current. Wide bandwidth output transformers for single ended and pushpull vacuum. Full geometric balance for near perfect phase splitting. The hammond series appears to be a larger transformer. Hammond 124 series tube driverinterstage transformers, designed for general purpose or replacement use in pushpull or phase inverter tube driver circuits. I have numerous times in the past used the pt156 from aes. Tube amplifiers and interstage transformers audiogon.
Merren audio provides custom wound transformers for both output and power applications including chokes. Its important to remember that when theyre talking about audio interstage transformers, and refer to 3. Much which follows on the topic of audio transformers is of necessity somewhat over simplified to give a general overview. Transformers in this category are hermetically sealed and of higher impedance than 1k ohms. 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. If you are looking to replace radiola iiia audio transformers, check out our universal radiola replacement unit. Antique radio forums view topic helpinterstage audio. Original transformer primary went open after about a month when restored set started being used 23. I replicated the circuit faithfully with an exception of the interstage transformers. Satellite tv equipment free delivery possible on eligible purchases. Audio interstage transformers antique radio forums.
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. For model audio interstage transformers for replacement, atwater kent mfg. When inquiring about toroid transformers from primrose audio, provide a full. Transformers lightning strike audio cassette by ladybird books childhood throwback, the transformers childrens books by ladybird came with an audio. Perfect drop in replacement for audio interstage transformer for gibson white panel amps that use a transformer for phase inverter.
Used it to replace a driver transformer for pp 45s in a gm253 lowboy ca. 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. 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. Sakuma says it is easy to build from a reference book or from mj. Designed for general purpose or replacement use in single ended or phase inverter tube driver circuits. 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. Audio transformer and impedance matching transformer. Most people ive seen tend to comment that the 6s45pe performs ideally at 40ma and above. Hi all, started digging into this columaire8 and find the primary on the insterstage. Our range of high quality audio transformers continuous to improve and expand. Transformer audio interstage, 10 ma antique electronic. 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.
They have a 100v rating but many sets only run 90 volts anyway. 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. I notice lots of old tube gear like pultec eqs, universal audio 175s have interstage transformers. Audio interstage transformers for radio part atwater kent mf. 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. Extensive range of performance audio transformers shipped worldwide delivery updated 6th april 2020 please look below for the latest situation. Audio transformers signal level, speaker level, tube audio. 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. New universal interstage transformer, 20,000 ohm ct primary with 80,000 ohm quad split secondary. 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. 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.
Antique radio forums view topic audio interstage transformers. Transformer audio interstage, 10 ma ce distribution. Connect the grnyel wire to the grn wire and the blkyel wire to the blk wire. Interstage audio transformer too old to reply nelson 20040216 05. This in turn has lead to improvements in tone and musicality, even if measured response has changed little.
Audio interstage transformers from scrap canadian vintage. Allows you to use your original laminations and housing. I believe the tranny is a audio interstage transformer but not sure that is the proper name. High quality audio transformers sjs electroacoustics. This is a universal replacement type it will replace any of the. Interstage transformer question the radioboard forums. Just had to play with the capacitor value to get the bass response back to original. Audio interstage transformers are hard to get now, and this is a good source. I took some ohmvoltage measurements with a standard ohm meter while the tranny was totally. Henney, k radio engineering handbook mcgrawhii book co. Home the canadian vintage radio society, and its bimonthly publication, canadian vintage radios, is dedicated to the preservation, restoration, collection and. Audio transformers were originally used in valve or tube amplifiers as interstage and output transformers. When conventional design practice is applied to this type of transformers you easily get destructive capacitive coupling between the primary and secondary windings. About us the canadian vintage radio society is dedicated to the preservation, restoration, collection and enjoyment of antique radios and related items.