When I first got my HT-44 running, I was using a high impedance Heathkit microphone and had no trouble achieving full output from the HT-44 with a relatively low mic gain setting (around 3).? When I switched over to the main station microphone, an Inrad M629 dynamic (600 ohm impedance), the best I could do was around 50 watts output with a mic gain setting around 8 on the HT-44.? I also have a Drake T-4XC which has a high impedance input and had the same result with the Drake.? I looked around for a reasonably priced solution and found this:
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It's a model CP8201 inline impedance transformer sold under the ATUS label and manufactured by Audio-Technica.? The primary impedance is 250 ohms and the secondary is 50,000 ohm.? ?Input is a three pin female XLR connector and the output is a 1/4 inch plug.? The price of the device is around $15.? My Inrad mic uses an XLR cable and I installed the device inline at the end of the mic cable and made another short cable to connect to the HT-44.? The matching device solved the problem with using the dynamic mic with the HT-44 and I am able to achieve full output with the mic gain set around 3 on the HT-44, same as with a high impedance mic.? There are many other types of matching transformers available on eBay, most being a bit more expensive than this one.? Another good source of matching devices is Reverb.com, but prices are a bit higher there.
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73, Floyd - K8AC
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Floyd - K8AC