hey all, hope you’re well.

I have recently purchased an Electro Harmonix 12ay7 mic pre & it’s left me with nothing but problems.

I bought this item brand new from a UK retailer on 19/4, received it on 29/4 & contacted them on the 1/5 only to be told I wouldn’t be allowed a refund as the 7 day return period was past??

I have tested the pre with my electro voice re-20 dynamic microphone going into the 12ay7 mic pre & then connected to my focusrite saffire pro 14.

I immediately noticed a lot of hiss & humming when I listened to my recording.
Having searched the internet for answers, I read about many others having similar problems. Kindly someone suggested I insert an impedance transformer after the mic pre & before my saffire pro 14.

I did as suggested & with the low impedance setting, the hum was quite reduced, however the hissing is ever present.

I notice that the noise is present as long as the unit is connected, it doesn’t change with volume or gain changes.

I’ve had plenty other pre’s & never had this issue.
I’m not currently working due to health reasons & cannot afford to just lose this type of money.

If anybody could help resolve this issue I’d greatly appreciate it as it sounds like it could be good without the hiss but I’m distraught at the thought of being left with a dud.