• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
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Eico HF-81 8ohm with Philips 800 ohm speakers

Hello everyone

I got a pair of Philips 9710AM/01 800ohm speakers and when was about to connect it to my Eico Hf-81 I realized there is inconsistent impedance, since the Eico is 8 ohm

Does anyone knows if need a matching transformer, or if I could just connect the Philips to the 8 ohm terminal of the amp?

I already have a pair of those matching transformers but I’m not sure if it’s a safe idea to connect them

I’m attaching picture of the speakers and transformers, they are quite beefy

Thanks !


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Thank you everyone !

Getting a dedicated Philips amp is not possible for availability in Buenos Aires (I’m from Argentina) and because I really love the sound of my Eico.

The transformers were built to spec for this particular use and are really heavy and big. So that you get a reference in this picture they are positioned within the cabinet

I will try it in the following weeks hopefully, and get back to you with the results

Thanks for your help !


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A pair of Philips 9710/01AM are quite valuable, and are also quite frail because the voice coil is wrapped with very fine wire to get the high impedance. I would be surprised if they were not valuable, since there are people who would like to emulate the Sonab OA6 Type 1 loudspeakers (that used EL86 in a totem pole arrangement to drive that type of loudspeaker without an output transformer), or who may have an old Philips amplifier like the AG9014 that only works with that impedance.
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