hd650 krell ksa5 clone headphone rig

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Nov 2017

My day to day headphone system. Not much to brag about… but still very good.

Sennheiser HD650 headphones. Modified with 3 custom cables to fit my mood. The stock cables are seen in the picture.
Yulong D100 DAC MK1 version. Modified and running a quartet of AD8620 opamps inside. (power switch in front is my addition)
Krell KSA5 Clone Class A Power Amplifier. Modified from the original design with an improved servo correction and more output power.
Laptop (PC) and DIY USB cable for the DCA

Running JRivers with Convolution plugin. The DSP allows the headphones to be flat from 18 Hz to ~18 kHz. I use Fabfilter pro Q and apply ~16 dB worth of correction to get the sound I want. The DSP'ed HD650 is simply hard to believe. Put on some digital and they’ll deliver!

I'm still using the overkill KSA5 clone that I had built for my now sold HifiMan He-6, as they required a solid amplifier to sound their best.

I thought about selling the KSA5 because the modified Yulong output stage (textbook diamond buffer circuit) was good enough to power the HD650 and the easy 300 ohms load they represent.

Man…was I wrong!!! Despite the extra complexity and wiring, the Krell KSA5 clone just sounded better in all areas. Didn’t take me long to realize that the KSA5 is a keeper. The bass and dynamics are simply superior to the diamond buffer in the Yulong headphone section. No contest here folks.

I plan on building a LME49600 based headphone amplifier to compare it against the old school Krell KSA5 to see if it still has the edge. While Krell used the Jfet input, I find Jfet input often don’t offer the best sonics. Often, they restrict the perceived dynamics.

As a speaker amplifier, the KSA5 works OK, but falls short in the bass authority department and seems to miss on the micro-details. I tested a friend’s 90 Bb/w Yamaha NS1000 speakers, since I’m quite familiar with those speakers, and there was absolutely no doubt about the KSA5 shortcomings.

Of course, it’s nothing to be ashamed about. Is the average audiophile headphone amplifier capable of 7 watts RMS under 8 ohms? Can’t it power 90 dB speakers at moderate listening levels?

In a word…NO. The Krell KSA5 does, it find it difficult but it can.

Update January 2021,

As per above picture, beside my Sennheiser HD650 full size headphone, I also own 2 pairs of IEM's.

I started with the Shure SE215 and liked them a lot, I think they are 8 or 9 years old. I used them for walking, cycling, running and they are very well worn in.

One day, I got an intermittent signal on the Left and I've bought a replacement cable thinking it had served me for quite a long time already . Broken wires are a given fact of life with IEM's. Sadly, the cable wasn't the fault and I had a SE215 dead... What a pain, I loved them, do I buy a new pair or upgrade them?

Having some spare change around, I bought a pair of NOS SE535. They used to be Shure's flagship until the introduction of the SE846. I've figured out they were worth a try given how much I liked my SE215.

Disaster, I hate them! the midrange is forward, too much in prominence and the bass is much behind. They have no slam or perceived impact, they sound like a cheap full range speaker, not like a TOTL product... Treble is slightly better than the SE215 but overall, I liked the cheaper SE215 much better. Yes, the 215 aren't as refined, efficient and give you more of a raw presentation but when walking and cycling, I don't look for ultimate resolution but enjoyment. The SE215 are warmth and well balanced.

I've opened the faulty SE215 with a knife and found out the wire soldered on the connector was broken. Look on YouTube for video on how to open them. BAM, what an easy fix. 10 minutes and I had saved my SE215.

Once you use an equalizer application to tune both IEM's, the SE535 still have more details and resolutions, you can bring back the bass somehow to an accurate level and they perform ok and never make you smile...

With a different Equalizer setting, the SE215 sound more full, more enjoyable, they give you slam, I still like them much better than the SE535.

If you look by my door, there are 2 hooks for IEM's headphones, too bad I almost always use the same one. What a waste of money the 535 were.

Also, EQ or not, both IEM's are leagues behind the Sennheiser HD650 in overall sound quality. But when being active, IEM's are pretty much your only choice.

Before someone ask, both SE215 and SE535 where bought from an authorized reseller as I didn't wanted to buy on Ebay or Amazon and risking getting fake product. (90% guaranteed to get a fake on Ebay and maybe 60/40 on Amazon. Such odds don't worth the potential saving)

Martin Poulin

Update January 2021,

As per above picture, beside my Sennheiser HD650 full size headphone, I also own 2 pairs of IEM's.

I started with the Shure SE215 and liked them a lot, I think they are 8 or 9 years old. I used them for walking, cycling, running and they are very well worn in.

Having some spare change around, I bought a pair of NOS SE535. They used to be Shure's flagship until the introduction of the SE846. I've figured out they were worth a try given how much I liked my SE215.

I've opened the faulty SE215 with a knife and found out the wire soldered on the connector was broken. Look on YouTube for video on how to open them. BAM, what an easy fix. 10 minutes and I had saved my SE215.

Once you use an equalizer application to tune both IEM's, the SE535 still have more details and resolutions, you can bring back the bass somehow to an accurate level and they perform ok and never make you smile...

With a different Equalizer setting, the SE215 sound more full, more enjoyable, they give you slam, I still like them much better than the SE535.

If you look by my door, there are 2 hooks for IEM's headphones, too bad I almost always use the same one. What a waste of money the 535 were.

Also, EQ or not, both IEM's are leagues behind the Sennheiser HD650 in overall sound quality. But when being active, IEM's are pretty much your only choice.

Before someone ask, both SE215 and SE535 where bought from an authorized reseller as I didn't wanted to buy on Ebay or Amazon and risking getting fake product. (90% guaranteed to get a fake on Ebay and maybe 60/40 on Amazon. Such odds don't worth the potential saving)

YMMV

Update January 2021,

​

As per above picture, beside my Sennheiser HD650 full size headphone, I also own 2 pairs of IEM's.

​

I started with the Shure SE215 and liked them a lot, I think they are 8 or 9 years old. I used them for walking, cycling, running and they are very well worn in.

Having some spare change around, I bought a pair of NOS SE535. They used to be Shure's flagship until the introduction of the SE846. I've figured out they were worth a try given how much I liked my SE215.

​

​

I've opened the faulty SE215 with a knife and found out the wire soldered on the connector was broken. Look on YouTube for video on how to open them. BAM, what an easy fix. 10 minutes and I had saved my SE215.

Once you use an equalizer application to tune both IEM's, the SE535 still have more details and resolutions, you can bring back the bass somehow to an accurate level and they perform ok and never make you smile...

With a different Equalizer setting, the SE215 sound more full, more enjoyable, they give you slam, I still like them much better than the SE535.

​

If you look by my door, there are 2 hooks for IEM's headphones, too bad I almost always use the same one. What a waste of money the 535 were.

​

Also, EQ or not, both IEM's are leagues behind the Sennheiser HD650 in overall sound quality. But when being active, IEM's are pretty much your only choice.

​

Before someone ask, both SE215 and SE535 where bought from an authorized reseller as I didn't wanted to buy on Ebay or Amazon and risking getting fake product. (90% guaranteed to get a fake on Ebay and maybe 60/40 on Amazon. Such odds don't worth the potential saving)

​

YMMV

​