Eric McChanson Headphone Amp??
May 11, 2014 at 10:36 AM Thread Starter Post #1 of 391

DMax99

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Hi guys,

I've come across this DIY headphone amplifier on eBay Australia. Its built by an aussie guy called Eric. He also has designed and built many other Hi Fi amps and selling them on eBay.

Has anyone any experience with his amp? I'm quite tempted to try one but thought maybe I would seek some opinions first.

Thanks
 
May 11, 2014 at 12:21 PM Post #2 of 391

kramer5150

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Is this the amp you are looking at?
http://www.ebay.com.au/itm/Eric-McChansons-Headphone-Amp-6S45P-Stereo-Valve-Tube-NEW-/111350153178
 
I can't offer first hand experience but heres my .02...
>Solid Ebay history, 1000s of transactions for tubes and guitar amps... all positive.  thumbs up on that.
 
>Ask him for pics of the internals.  P2P craftsmanship can vary greatly.  Theres some very shoddy/sloppy work out there that many (even the most experienced) builders hide under nice case-work.
 
>Ask him what volume pot he's using, there are some bad ones out there that have very poor channel balance characteristics at lower volume settings.  This is more important if you are a low volume listener.
 
>Ask him what output coupling capacitors he is using, why he chose those and why he chose values he is using.  This is one of the key elements to OTL amp design that experienced builders tinker and tweek with, it can have a dramatic impact on the sonic qualities of the circuit.  Any "professional" experienced headphone amp builder will have given at least some train of thought to component selection at this critical stage in the circuit. 
 
>Ask him for a schematic.  I would never buy someones DIY tube amp without one, or at the very least a URL link to a schematic.  P2P tube amps are fun little buggers.  The ability to repair and service them is a big bonus over SMT/PCBA designs.  You lose that bonus/perk to some degree without a schematic.
 
>He doesn't say it specifically what the Primary Vin is... 220 or 110... you'll need to confirm this, and its NOT something that should just be assumed.
 
>Most importantly you should inquire what power transformer he is using, and how its employed in the transformation.  If the transformer is a dual primary, and he is using one of those primaries as the secondary...  Thats a HUGE red flag, a UL violation... but most importantly its a fire and safety hazard.  I don't mean to be an alarmist, but there have been some questionable circuits out there... parading to be high end, yet failing this most basic fundamental. (David Yee audio and Singlepower come to mind immediately).
 
>This statement caught my attention "using the leads of the components as far as possible to minimize the need of  connecting wires."  Cutting, trimming, component termination and wire routing (done cleanly) is one of the elements I look for in a quality P2P build.  Its not an easy skill to master.  Some builders have a talent for it, most don't.  Cleanly routed signals is one of the things you are paying for when you purchase a well made P2P circuit from an experienced builder.
 
>His RCA inputs run through an A/B splitter switch.  Ask him if its a triple pole dual throw (3PDT) switch, where he's switching the input grounds as well as the + signals.  If he's only switching the + signals (DPDT) and common grounding all the "-" inputs, thats a red flag as this kind of circuit design can introduce ground loop noise on the inputs, depending on the overall "noise" environment around you.
 
These are all what I would consider very basic headphone tube amp fundamentals.  If he can't reply back with these questions answered, or simply refuses too outright... keep your $$ and walk away.  Its not like he's the only gig in town.
 
No experience with those tubes specifically, but his choice for driver tube is very common and inexpensive... thumbs up for that.  The output tubes are somewhat more rare / difficult to source... but not impossible.
 
Apr 25, 2018 at 8:12 PM Post #3 of 391

Chifley

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A review of the new McChanson 6EM7 SET headphone amp:

https://www.stereo.net.au/forums/to...t-headphone-amp/?tab=comments#comment-3888180

Hi from Sydney, Australia. I wrote this up the other day in appreciation of Eric Chan's McChanson tube amps.

I've been reading Head-Fi forums for a while now but I'm a relative newcomer to serious headphone listening. I moved into a smaller place last year and with insufficient room for my two-channel setup I put my Harbeth speakers and everything else into storage and delved into head-fi.

Over an 8-month period I tried numerous headphones (and quite a few amps) in all price categories. I found I preferred Grado, and eventually sold most of my other brands.

Cheers all.
 
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Mar 31, 2019 at 12:59 AM Post #4 of 391

Mr B1

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Hi from Sydney as well. I'm just having a very similar one (to Chifley's) build by Eric - he just finished it. Very exciting..! Slightly different aligned 'deck', couple of upgraded components plus a pre-out instead of 2 inputs. OI000083.JPG
 
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Feb 21, 2021 at 4:08 AM Post #5 of 391

UntilThen

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Today I get to try one of Mcchanson amp and it's a monster. Using Tung Sol current production KT150, 6EM7 as driver and GZ34 as rectifier tube. This amp output 12w in UL and 6.5w in triode mode. It's a stereo amp with no headphone output but Eric could have one put in, that's what my friend said. The amp was loan to my friend for evaluation. He had wanted a SET amp base on KT77 for primarily headphone usage but secondarily as a speaker amp.

This amp can accept KT150, KT120, KT88, KT77, EL34 and 6L6GC by manually adjusting the bias for different tubes. This particular amp is bias for KT150. Eric made a speaker taps cable out to 1/4 inch jack for my friend.

The amp was brought over to my home for evaluation. I've a Elekit TU-8200 which uses the same complimentary array of power tubes and a pair of 12au7 as preamp tubes. I've been very impressed with Elekit amp and when the preamp / phono stage TU-8500 arrived, it raise the level of SQ even further. I run GEC KT66, Philips Miniwatt 6CA7 and Telefunken EL12 spez in it and it is such an astounding sounding amp.

So when Mcchanson KT150 amp arrived, I was very curious to know how it would fare against the Elekit combo. No headphone out means I have to use the speakers tab cable with my He1000se and LCD-3f.

Gingerly I connected the sacrificial LCD-3f first to the amp and started to listen to the first song, increasing the volume very slowly. A big smile broke out when I hear music and it's blossomed out, great bass and sounded very detailed. It's organic for sure and not mid centric like the 300b tubes. High frequencies, mid-range and bass are handled very well. I was very surprised that this speaker amp sounded very good with LCD-3f. Next I swap to the HE1000se and was equally astonished that it drove the HiFiMan like a maestro.

How did it differ from my Elekit combo? The KT150 amp is fuller, more meat to the bones and more bloom. Elekit combo is tighter, more precise and has better stereo imaging with Telefunken EL12 spez and Brimar 12au7 long plates tubes. Which do I prefer. Hard to say really. The audition was one hour short because we had to go to another friend's place. However this short session has left me pretty impressed with Mcchanson KT150 amp. I believe that using KT77 or EL34 or KT88 would have been better suited for headphones but there's a lot of potential for this amp. Perhaps if I had more time with it, I would have like it more.

Anyone looking for a competitor to the Elekit TU-8200R or the TU-8800 should definitely audition a KT77 configured headphone / speaker amp from Mcchanson. For one, it's quite cheap and sound great and the build though a bit on the traditional no frills look, does look smart in black. I wish I could have kept it for a week but let's hope my friend order the KT77 version and then I'll be able to try it for a longer time.

Final note: I was holding back on my praise of this amp. Didn't want to appear to fall head over heels on first listen of this KT150 amp. The truth is I was very impressed and I could tell you that I would want to own one and the listed price is just AUD$1900.

Some pictures and it sure look very pretty for the budget price.

IMG_1925.jpg

IMG_1930.jpg

IMG_1927.jpg

Speaker taps cable to the xlr connection of the headphone jack. It a SE amp. The xlr out is just for convenience.
IMG_1929.jpg
 
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Mar 9, 2021 at 4:25 AM Post #6 of 391

xtiva

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Today I get to try one of Mcchanson amp and it's a monster. Using Tung Sol current production KT150, 6EM7 as driver and GZ34 as rectifier tube. This amp output 12w in UL and 6.5w in triode mode. It's a stereo amp with no headphone output but Eric could have one put in, that what my friend said. The amp was loan to my friend for evaluation. He had wanted a SET amp base on KT77 for primarily headphone usage but secondarily as a speaker amp.

This amp can accept KT150, KT120, KT88, KT77, EL34 and 6L6GC by manually adjusting the bias for different tubes. This particular amp is bias for KT150. Eric made a speaker taps cable out to 1/4 inch jack for my friend.

The amp was brought over to my home for evaluation. I've a Elekit TU-8200 which uses the same complimentary array of power tubes and a pair of 12au7 as preamp tubes. I've been very impressed with Elekit amp and when the preamp / phono stage TU-8500 arrived, it raise the level of SQ even further. I run GEC KT66, Philips Miniwatt 6CA7 and Telefunken EL12 spez in it and it is such an astounding sounding amp.

So when Mcchanson KT150 amp arrived, I was very curious to know how it would fare against the Elekit combo. No headphone out means I have to use the speakers tab cable with my He1000se and LCD-3f.

Gingerly I connected the sacrificial LCD-3f first to the amp and started to listen to the first song, increasing the volume very slowly. A big smile broke out when I hear music and it's blossomed out, great bass and sounded very detailed. It's organic for sure and not mid centric like the 300b tubes. High frequencies, mid-range and bass are handled very well. I was very surprised that this speaker amp sounded very good with LCD-3f. Next I swap to the HE1000se and was equally astonished that it drove the HiFiMan like a maestro.

How did it differ from my Elekit combo? The KT150 amp is fuller, more meat to the bones and more bloom. Elekit combo is tighter, more precise and has better stereo imaging with Telefunken EL12 spez and Brimar 12au7 long plates tubes. Which do I prefer. Hard to say really. The audition was one hour short because we had to go to another friend's place. However this short session has left me pretty impressed with Mcchanson KT150 amp. I believe that using KT77 or EL34 or KT88 would have been better suited for headphones but there's a lot of potential for this amp. Perhaps if I had more time with it, I would have like it more.

Anyone looking for a competitor to the Elekit TU-8200R or the TU-8800 should definitely audition a KT77 configured headphone / speaker amp from Mcchanson. For one, it's quite cheap and sound great and the build though a bit on the traditional no frills look, does look smart in black. I wish I could have kept it for a week but let's hope my friend order the KT77 version and then I'll be able to try it for a longer time.

Final note: I was holding back on my praise of this amp. Didn't want to appear to fall head over heels on first listen of this KT150 amp. The truth is I was very impressed and I could tell you that I would want to own one and the listed price is just AUD$1900.

Some pictures and it sure look very pretty for the budget price.







Speaker taps cable to the xlr connection of the headphone jack. It a SE amp. The xlr out is just for convenience.
Oh nice write up Matt!!! didn't know you wrote it up... anyway mine is getting built at the moment.
Will bring it over once I pick it up so that you can critique for me :)

Latest update from Eric :)
DSCN8826.JPG
DSCN8830.JPG
 
Mar 9, 2021 at 5:00 AM Post #7 of 391

UntilThen

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Sure @xtiva , would love to have a listen when it’s finished. So this is bias on KT77?
 
Mar 9, 2021 at 5:03 AM Post #8 of 391

xtiva

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Sure @xtiva , would love to have a listen when it’s finished. So this is bias on KT77?

Yeah it would be KT77 biased.

actually just got another update from him today

He told me he will need to do the under top panel soldering

Got 4-pin XLR connector as well so I wouldn't need adapter :)

Pitty tube is about 2 weeks away according to Eric...

DSCN8837.JPG
 
Mar 9, 2021 at 5:06 AM Post #9 of 391

UntilThen

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Coming along nicely. Old school indeed.
 
Mar 9, 2021 at 5:17 AM Post #10 of 391

xtiva

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Yeah it indeed looks old school :)
 
Mar 9, 2021 at 8:06 PM Post #11 of 391

xtiva

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Mar 9, 2021 at 8:37 PM Post #12 of 391

UntilThen

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Looks like Eric completed the build... just waiting for the Tube... :)
Holy Christmas that look nice but it’s a very wide amp. You need a big desk now.

Shall we trade amp? I’ll give you my Elekit TU8500 and TU8200 for that KT77 amp. 😊
 
Mar 9, 2021 at 8:43 PM Post #13 of 391

UntilThen

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Bring it to my place in 2 weeks time and I’ll give you my unbiased opinion. 🤗
 
Mar 9, 2021 at 9:05 PM Post #14 of 391

xtiva

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Bring it to my place in 2 weeks time and I’ll give you my unbiased opinion. 🤗
LOL LOL Elikit might be better. Yeah def will seek your expert opinion.. but it might be burned in yet. :)
 
Mar 13, 2021 at 6:33 AM Post #15 of 391

xtiva

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Bring it to my place in 2 weeks time and I’ll give you my unbiased opinion. 🤗

getting daily update on the amp progress anyway he said all the wiring will be done by tomorrow :)

below is the today's update... can't wait...
DSCN8857.JPG
 

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