Suggestions for 60ohm to 120ohm earbuds

[pollock0424]

Hello,
I'm looking for wired earbuds/hybrid headsets within 60 to 120ohm impedance. It will be used only for music. Currently, I have Samsung S10/AKG earbuds and Bose Soundsport. I prefer the AKG as they sound neutral (close to harman curve). I won't be able to use an EQ.

If you have some lying around then I'm willing to buy it also.

 

[staticV3]

Why 60 to 120ohm impedance?

 

[pollock0424]

I'm using it with portable cassette media (Nakamichi 550 and Sony WM D6). I just thoroughly refurbished these and it is my hobby.

Sony uses a NJ386DE, it is a quite capable opamp but the power supply is starved..

Nakamichi uses a fully discrete headphones amp section and runs at 12v, common collector class A followed emitter follower class AB. Has plenty of juice because it uses 8xD cells.

I upgraded the output coupling cap on Sony from 100uF to 220uF and Nakamichi from 100uF to 330uF. I have seen a good improvement in bass and overall tonality so far with AKG (Samsung) buds.

I can't go very low impedance and at the same time I can't go higher for power and efficiencyreasons.. I figured 60 to 120 is reasonable. I used my Sennheiser HD660 with Nakamichi and was surprised to see how it was driven... however, HD660 really needs EQ and that's why Harmon compliant buds are a must for this app.

Typically I use my Sennheisers with Sabaj A10h and Yamaha C85 preamp(has parametric tone controls and variable loudness)

 

[pollock0424]

Okay, I returned the 7Hz before because they sounded tinny prior to cap upgrade but i wanted to see how they will sound now and boy..do they sound good. I'm happy

 

[tjf]

Wow -- Nak 550 (wasn't this the large chassis portable with the cassette door on the top panel surface?) AND a WM-D6 (I had a D3) - the "Walkman Pro" -- wow - glad to see someone working on/refurbishing these guys...

have you considered a battery powered headphone amp - I use the Topping NX7 ( I've also used the smaller Fiio A3 - but it might be extinct) - but the NX7 sounds quite good and uses the Topping NFCA amp topology -- and will present either of your players headphone amplifiers with a high impedance load - the NX7 has a high gain mode which might help you get the drive levels you want -- this way you can use whatever IEM/Headphone you like, and just have the amp attached (velcro?) to the cassette players?

TOPPING NX7 Portable Headphone Amplifier

The TOPPING NX7 is a portable amplifier with the features that count: incredibly low distortion, 20 hour battery life, and loads of output power. NFCA amplifier The new NFCA amplifier circuit was specifically designed for portable amplifiers. With a THD+N of 0.00007% and an SNR of 135dB, the NX7...

apos.audio

 

[Dunring]

Can't you just add one of these? They're $3 and then the world is your oyster for headphone or IEM selection.

https://www.aliexpress.us/item/3256805826505162.html

 

[pollock0424]

Can't you just add one of these? They're $3 and then the world is your oyster for headphone or IEM selection.

https://www.aliexpress.us/item/3256805826505162.html

What is this ? Pardon my ignorance..

 

[pollock0424]

@tjf

I thought about that but I still can't use my Sennheiser HD660 because it requires EQ. With current capacitor increase mod, I can use a wide variety of phones that comply to Harman curve. Have you seen any portable amps with at least a bass boost ?

Here's some more interesting info about the 550.

Mike Millard - Wikipedia

en.m.wikipedia.org

Also, I was expecting to be disappointed but the 550 and the D6 sound good! Much respec for boomer generation that lugged around the 15lb 550 that was masquerading as a portable.

 

[tjf]

@tjf

I thought about that but I still can't use my Sennheiser HD660 because it requires EQ. With current capacitor increase mod, I can use a wide variety of phones that comply to Harman curve. Have you seen any portable amps with at least a bass boost ?

Here's some more interesting info about the 550.

Mike Millard - Wikipedia

en.m.wikipedia.org

Also, I was expecting to be disappointed but the 550 and the D6 sound good! Much respec for boomer generation that lugged around the 15lb 550 that was masquerading as a portable.

The little Fiio "A3" amp has bass boost - but soundwise the NX7 kills it, especially if you need high gain/voltage output.

Yeah...EQ is gonna be a problem due to the analog output of the players -- I don't know of a portable device (maybe something exists in the pro/musician market?) that has a ADC and DSP/EQ-to-DAC capability - but all the devices I'm aware of assume you're starting out with a digital signal (usually a USB) source -- or if you don't need a portable solution you could go the MiniDSP route with a Flex, etc.?

miniDSP Flex

Pocket size processor with flexible Input/Output configuration, Audiophile converters, 400MHz Sharc DSP processor, BT connectivity, DSP toolbox for subwoofer and multiway crossover, Dirac Live optional upgrade

www.minidsp.com

You could try the Schiit "Lokius" EQ -- but it's a pretty basic analog EQ (Bands: 20Hz, 120Hz, 400Hz, 2kHz, 6kHz, 16kHz -- with some @ +/-12db/9db/6db -- and variable "Q" or bandwidth depending on how much boost/cut you use (higher levels of boost/cut become narrow band or "high Q" bandwidths - low amounts of boost/cut are wide band - 1 Octave maybe?) -- it seems to be a decent circuit from a SINAD perspective -- but you can't call this solution "portable" at all -- and uses a power supply that gives 14V-16V AC power out -- so no "battery" power options -- maybe other guys here can suggest a "Pro" option for EQ/DSP/ADC-DAC functions...

Schiit Audio: Audio Products Made in USA

www.schiit.com

Or use a full size headphone with the Nak/Sony+NX7 amp that has good compliance with the Harman curve - my preference is for Beyer DT900 ProX or HiFiman HE400SE

The Nak 550 was a pretty cool item -- I remember them being used for field recordings for film/video production and for live concert tapes -- a favorite for Grateful Dead-Heads recording "bootleg" tapes to trade/swap with tapes made at other GD shows around the U.S./World -- back in the 70s/80s as I recall -- especially with the built-in mic mixer for stereo mic setups


I understand you've worked on the audio electronics for the headphone outputs -- but upkeep on the cassette transport mechanisms would be a pain I imagine...

 

[pollock0424]

I'm tempted to rig it with a bass booster circuit. Yeah, what makes decks challenging is that mechanical and electrical issues feed off of each other. Once refurbished, these 550s can work for another 10 years easy..unlike other fullsize/portable decks.