Hi,
I have a collection of Koss ESP 9 energizers (E9). There are four in all. All work and one is in very good condition as it was boxed for most of it's life. There is one original box that the best E9 was in and a fully functional ESP 9 'phone that is not part of that set, but from another set. I have it's energizer in this group, too. That energizer is in OK condition and 2 energizers are a little rough.
There is also a pair of rare ESP 8 'phones that worked when they went into the box many years ago, but they now have one driver out. I simply don't understand why the ESP 8's do not work? Also there is an original Owners Manual for the ESP 9.
Both 'phones had original foam that turned into some kind of muck. I carefully cleaned it out and put new foam in. The working set sounds good even after all the years. My vision is too poor to do much in the way of mods, so I'll let them go.
I can send details and photos to serious inquiries. A serious inquiry means you accept that the firm price is 300 plus shipping for all.
An experimenters delight, but you can simply listen to a working pair while you experiment.
I have a collection of Koss ESP 9 energizers (E9). There are four in all. All work and one is in very good condition as it was boxed for most of it's life. There is one original box that the best E9 was in and a fully functional ESP 9 'phone that is not part of that set, but from another set. I have it's energizer in this group, too. That energizer is in OK condition and 2 energizers are a little rough.
There is also a pair of rare ESP 8 'phones that worked when they went into the box many years ago, but they now have one driver out. I simply don't understand why the ESP 8's do not work? Also there is an original Owners Manual for the ESP 9.
Both 'phones had original foam that turned into some kind of muck. I carefully cleaned it out and put new foam in. The working set sounds good even after all the years. My vision is too poor to do much in the way of mods, so I'll let them go.
I can send details and photos to serious inquiries. A serious inquiry means you accept that the firm price is 300 plus shipping for all.
An experimenters delight, but you can simply listen to a working pair while you experiment.
Some details about the Koss E9 energizers:
12:33 PM 2/9/2022
Notes on Koss E/9 energizers
Seattle pair, No 1
Has Patent 3,632,903
Has S/N 9T01C1 Printed on bottom tag
Single small black bias transformer high on back panel screws visible on outside of back panel
Cover has two holes that do not attach to anything ( see Boston model)
Fused
Bias 212 and 215
Seattle pair No 2
S/N 424152 Hand written on bottom white tag
Cover has two holes that are not attached to anything inside
Fused
Same Patent as Seattle pair No 1
Bias 160 both channels
Single small black bias transformer
Boston model stil has it's original spade lugs on cable to amp)
This energizer came with the functional ESP 9 'phones
Bias 197, both channels
Patent Pending
No S/N
Fused
Cover has two holes that attach to transformer rack
Two silver bias transformers
My original warranty return from Durango Music, purchased from distributer with defective left channel
ESP 9 from the set Burned up on E8 Self Energizer; so did energizer
Original box with P/N
S/N 443101 hand written on bottom tag
Fused
Two circuit breakers identified as Right and Left, factory stock
No bias transformer! The rack used to support bias transformers in other models supports a daughter board that contains diodes and disc caps; the bias circuit?
Bias 93 both channels
Patent Pending
Very clean inside
'
12:33 PM 2/9/2022
Notes on Koss E/9 energizers
Seattle pair, No 1
Has Patent 3,632,903
Has S/N 9T01C1 Printed on bottom tag
Single small black bias transformer high on back panel screws visible on outside of back panel
Cover has two holes that do not attach to anything ( see Boston model)
Fused
Bias 212 and 215
Seattle pair No 2
S/N 424152 Hand written on bottom white tag
Cover has two holes that are not attached to anything inside
Fused
Same Patent as Seattle pair No 1
Bias 160 both channels
Single small black bias transformer
Boston model stil has it's original spade lugs on cable to amp)
This energizer came with the functional ESP 9 'phones
Bias 197, both channels
Patent Pending
No S/N
Fused
Cover has two holes that attach to transformer rack
Two silver bias transformers
My original warranty return from Durango Music, purchased from distributer with defective left channel
ESP 9 from the set Burned up on E8 Self Energizer; so did energizer
Original box with P/N
S/N 443101 hand written on bottom tag
Fused
Two circuit breakers identified as Right and Left, factory stock
No bias transformer! The rack used to support bias transformers in other models supports a daughter board that contains diodes and disc caps; the bias circuit?
Bias 93 both channels
Patent Pending
Very clean inside
'
Hi, yes I still have them I am tied up in a large project and responses might be slow, but if you want me to send pics I can do that.
Scott
Scott