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SAE Amplifier Emitter Resistors

Henry Griffin All Messages By This Member #17452 Does anyone know if the emitter resistors used in SAE amplifiers are of the non-inductive type?? I have a SAE 3100 that needs a new .2 ohm 5W cement resistor in the output section.? There is little information on the resistor besides its value, power rating, and its manufacturer, Micron.? Reviewing available information from the internet doesn't help answer the question. Does anyone know for sure?
mikehr2 All Messages By This Member #17453 开云体育 toggle quoted message Show quoted text On Oct 16, 2020, at 11:30 AM, Henry Griffin via groups.io <sustainedreaction@...> wrote: ?Does anyone know if the emitter resistors used in SAE amplifiers are of the non-inductive type?? I have a SAE 3100 that needs a new .2 ohm 5W cement resistor in the output section.? There is little information on the resistor besides its value, power rating, and its manufacturer, Micron.? Reviewing available information from the internet doesn't help answer the question. Does anyone know for sure?
Henry Griffin All Messages By This Member #17454 Thanks for the link mikehr2.? Lots of interesting information but I didn't see anything about whether SAE used non-inductive emitter resistors in the 3100.? If its there could you point it out to me? Still looking for the answer.
Goran Finnberg All Messages By This Member #17455 Henry Griffin: >whether SAE used non-inductive emitter resistors in the 3100.? >Still looking for the answer. I knew the SAE agent here in Sweden. I repaired faulty SAE gear in my part of Sweden. I asked the factory via Telex about the emitter resistors and the straight answer was that they were normal inductive power resistors. Nothing fancy at all. I will say that this answer is what 99.9999% of all amplifiers at that time used. With the best power transistors having an Ft of barely 2 MHz and the closed loop unity gain at around 500 kHz to keep the amplifier from oscillation due to cumulative phase shift, Nyquist criteria,? there simply would not be any use for non-inductive resistors. Modern amps using ring emitter power transistors with an Ft of 50 MHz might use non inductive emitter resistors if the designer felt it useful. But even today most normal standard product do not use non-inductive emitter resistors for the gain is zero and total Bill Of Materials, BOM, cost must be held as low as possible to meet the target price in the street and still allow a profit. _._,_._ -------- Best regards, Goran Finnberg The Mastering Room AB Goteborg Sweden E-mail: mastering@... Learn from the mistakes of others, you can never live long enough to make them all yourself.??? -?? John Luther (\__/) (='.'=) (")_(") Aron, VovVov, Nero & Smurfen:RIP
Scott Svare All Messages By This Member #17456 开云体育 Great answer Goran. That is the kind of straight forward information that solves problems. Everything is always up for debate and different theories… but I will take 99.9999% of what is used as almost 100% of the time! Thanks, Scott Scott Svare Global Press, Inc. 206-369-7040 globalpress@... toggle quoted message Show quoted text On Oct 17, 2020, at 11:14 AM, Goran Finnberg <mastering@...> wrote: Henry Griffin: >whether SAE used non-inductive emitter resistors in the 3100.? >Still looking for the answer. I knew the SAE agent here in Sweden. I repaired faulty SAE gear in my part of Sweden. I asked the factory via Telex about the emitter resistors and the straight answer was that they were normal inductive power resistors. Nothing fancy at all. I will say that this answer is what 99.9999% of all amplifiers at that time used. With the best power transistors having an Ft of barely 2 MHz and the closed loop unity gain at around 500 kHz to keep the amplifier from oscillation due to cumulative phase shift, Nyquist criteria,? there simply would not be any use for non-inductive resistors. Modern amps using ring emitter power transistors with an Ft of 50 MHz might use non inductive emitter resistors if the designer felt it useful. But even today most normal standard product do not use non-inductive emitter resistors for the gain is zero and total Bill Of Materials, BOM, cost must be held as low as possible to meet the target price in the street and still allow a profit. _._,_._ -------- Best regards, Goran Finnberg The Mastering Room AB Goteborg Sweden E-mail: mastering@... Learn from the mistakes of others, you can never live long enough to make them all yourself.??? -?? John Luther (\__/) (='.'=) (")_(") Aron, VovVov, Nero & Smurfen:RIP
Michael All Messages By This Member #17457 Try KOA Speers BPR58CR22J.? It's a 5 watt .22 ohm non inductive, metal foil design.? I've used this for years,? Mouser has stock on them and they are under a buck a piece.? They are radial leads but I believe there may be an axial lead version, although I didn't look.? Regards, Michael Bettinger
mikehr2 All Messages By This Member #17458 开云体育 Hi Everyone, The low ohmic emitter resistors used in SAE power amps and many others from the 70'/80's in this application with power transistors can be can be inductive, low inductance or non inductive types. At time of design and production cost is always a concern so usually a general use cement/sand type inductive resistor is used to keep costs under control. Here is one I found to be NON INDUCTIVE in a AXIAL case style. They are available from Mouser @ $ 1.16 if you purchase 10 or more. Hope this helps in your 3100 repair. mike Vintage Audio Labs toggle quoted message Show quoted text On Oct 17, 2020, at 9:07 PM, "Michael" <mikebettinger@...> wrote: Try KOA Speers BPR58CR22J.? It's a 5 watt .22 ohm non inductive, metal foil design.? I've used this for years,? Mouser has stock on them and they are under a buck a piece.? They are radial leads but I believe there may be an axial lead version, although I didn't look.? Regards, Michael Bettinger
Henry Griffin All Messages By This Member #17459 Thanks for the follow up Mike.? Could I get the manufacturer and part number of the resistor you were referring to in your post? Thanks to all of you for taking the time to provide your insights and information.? While researching non-inductive resistors I came across a forum thread where a Caddock high-powered film resistor was used as a replacement for these emitter resistors.? I also came upon non-inductive wirewound power resistors from China on eBay.
mikehr2 All Messages By This Member #17460 开云体育 toggle quoted message Show quoted text On Oct 17, 2020, at 9:07 PM, Michael <mikebettinger@...> wrote: ? Try KOA Speers BPR58CR22J.? It's a 5 watt .22 ohm non inductive, metal foil design.? I've used this for years,? Mouser has stock on them and they are under a buck a piece.? They are radial leads but I believe there may be an axial lead version, although I didn't look.? Regards, Michael Bettinger
Henry Griffin All Messages By This Member #17461 Thanks Mike.
mikehr2 All Messages By This Member #17462 开云体育 My apologies to you and the group. The link I posted was a .022 ohm not a .22 ohm that you require.? toggle quoted message Show quoted text On Oct 20, 2020, at 11:27 AM, Henry Griffin via groups.io <sustainedreaction@...> wrote: ?Thanks for the follow up Mike.? Could I get the manufacturer and part number of the resistor you were referring to in your post? Thanks to all of you for taking the time to provide your insights and information.? While researching non-inductive resistors I came across a forum thread where a Caddock high-powered film resistor was used as a replacement for these emitter resistors.? I also came upon non-inductive wirewound power resistors from China on eBay.

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