Eros Tape Preamp HF adjustments?

[U47]

Hi
I am borrowing an old Eros Tape head preamp and am using it with a high output Nortronics head(430 mH). The gain was too low with a standard Otari head. Does it have HF adjustment pots as stock? My HF is WAY down at present and the bass seems a bit boosted. My 65 year old Marantz 7 has a HF adjustment for tape on the back panel. Sound is pretty good otherwise so far.
Thanks
Rich

 

[Doc B]

HF adjustment is done by changing the input resistor value. Typically the resistor in there is 90K to 100K ohms to work with repro heads with an inductance around 200mH. But on an old preamp it could have been changed by a previous user. For a high inductance head you might try changing it to something like 270K ohms. I recall a value around there working well with an older Ampex head that was around 500mH, though that was about 25 years ago and my memory may be off a bit. Ultimately you could install a trim pot. We used a fixed value because most all of our customers used decks with more common medium inductance heads around 200mH.

 

[U47]

Hi Doc
Thanks. I'll try changing the input resistor and see how it works out.

Rich

 

[U47]

It is in good company with the Doshi and King/Cello preamps. I like all three of them



R