Eico HF-85 volume pot

[vendo81]

Any suggestions on a good volume pot for an upgrade in an Eico HF-85? It is a dual 500K with dual 50K taps so I think it may be difficult to find a replacement. I've heard of people using An ALP's pot but I couldn't
't find one with dual 50K taps.

 

[century tek]

Is the original shot?

 

[Omegaman]

My Eico AF-4 had a pot that did not track well. I used an Analog meter to measure the ohms across the span.
The volume pot was matched at 12:00 and the tone pot was not used as much and was pretty well matched across the span

So I swapped the volume pot with the tone pot (same value) the volume pot worked okay in the 12:00 flat tone position and the other pot works well as volume

You can have Mark Oppat build new precise pots

 

[LexDM3]

So I swapped the volume pot with the tone pot (same value)...

That was a smart move on the AF-4 but that may not work on the HF-85. As the OP said, the HF-85's Volume pot (R1A, B) is 500K but also has a 50K tap. The HF-85's Treble pot (R3A, B) is a simple 500K pot so it likely won't allow a swap. Sorry but I don't know of a replacement.

 

[Omegaman]

That was a smart move on the AF-4 but that may not work on the HF-85. As the OP said, the HF-85's Volume pot (R1A, B) is 500K but also has a 50K tap. The HF-85's Treble pot (R3A, B) is a simple 500K pot so it likely won't allow a swap. Sorry but I don't know of a replacement.

Ahhh, I didn't notice the 50k tap.

 

[ferninando]

I used an ALPS pot for new vol pot in my 85 with no tap and everything works just dandy.
The 'loudness' switch is gone completely.

 

[k**rkleclaire]

My Eico AF-4 had a pot that did not track well. I used an Analog meter to measure the ohms across the span.
The volume pot was matched at 12:00 and the tone pot was not used as much and was pretty well matched across the span

So I swapped the volume pot with the tone pot (same value) the volume pot worked okay in the 12:00 flat tone position and the other pot works well as volume

You can have Mark Oppat build new precise pots

I second this, Mark built a volume pot for my HF-85, just be careful when you install as the back of the pot is not solid metal, it's a silver foil and easily pushed in, just a heads up the pot works great!

 

[ferninando]

Something to keep in mind is that vol pots are audio taper and tone pots are linear.
May affect how vol changes with pot rotation.

 

[vendo81]

Thank you all for the responses.
The pot works fine but is scratchy even after taking it apart for a good cleaning. I'll try to get it rebuilt as suggested as I'd like to keep the loudness switch.

 

[bobsnewname]

Any suggestions on a good volume pot for an upgrade in an Eico HF-85? It is a dual 500K with dual 50K taps so I think it may be difficult to find a replacement. I've heard of people using An ALP's pot but I couldn't
't find one with dual 50K taps.

Hi!
I have a few questions on my W-5Ms. What is your email address please? You mention ways to reduce the "strain" on the power transformer. WHERE is that discussed please?
Sincerely,
Bob, in Canada
BTW
I own an HF-85. I built one in 1961 when I was 17!
Sold it years ago, but have a replacement that I bought from a HiFi addict friend!