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SUPPORT FORUMS FOR ZKITS >> ZKIT 1 Support forum >> Right output transformer?
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Message started by Zach.Attaque on 03/05/25 at 15:36:14

Title: Right output transformer?
Post by Zach.Attaque on 03/05/25 at 15:36:14

Hello all, I've been sitting on the parts I ordered for the zkit1 a while ago and just getting around to putting them together, but noticing I may have the wrong Edcor output transformer. I purchased the 2 GXSE10-8K - 10W, 8K Ohms single ended guitar tube output transformer as recommended, though they are 4 ohm instead of the recommended 6. Is this something I can still use, if so, anything to keep in mind when wiring? Thank you for the help, Zach

Title: Re: Right output transformer?
Post by bobc on 03/05/25 at 22:11:59

It will work. As you know, the Kit specifies the 9800R->6R Edcor, with an 4 ohm load (your speaker impedance isn't fixed value) the tube sees a reflected impedance likely closer to 6500R. Reflected impedance make my brain hurt....

Ive built a couple versions with various rectifier options, using the 9800R >6R a 5000R>4 or 8R and a 6500R > 4 or 8ohms. My favoriate is the 6500R impedance, 4ohm tap, 8 ohm full range speaker, although the difference is slight on the 4ohm tap. On my o.g. zkit. with the recommended edcor in the basement now, I use RP600m, which are closer to 4 ohm, and they sound great. I read somewhere in this site that the new UFO transformers are 6.5k primary impedance into the 4/8 ohms.

You have an UL/screen tap on that transformer which should just be covered with a piece of heat shrink.. Or you could wire in on a switch off the 1k triode strap resistor.

Nonetheless you will make good music, it will work.

Title: Re: Right output transformer?
Post by Zach.Attaque on 03/05/25 at 22:47:57

Thanks for the thorough explanation and response--very helpful!