Musical Fidelity M1 HPA headphone amp upgrade kit

[PinkFloyd]

Coming soon........ the Musical Fidelity M1 HPA Headphone AMP Upgrade Kit.

I expect to launch it in February so watch this space.

Mike.

[bullpup]

Ah something new great! looking at the internal pictures on line there seems to be plenty of space in there.

[PinkFloyd]

Feb 15, 2017 14:17:08 GMT bullpup said:

Ah something new great! looking at the internal pictures on line there seems to be plenty of space in there.

There will be a preview in the work in progress thread tomorrow night Dave. I don't address the internal switched mode power supply, I leave it alone and accept it for what it is. Anyways..... a few internal shots of the upgrades tomorrow night and they "are" upgrades The stock amp sounded pretty strangled and you'll see why.

Best regards,

Mike.

[PinkFloyd]

Feb 15, 2017 14:17:08 GMT bullpup said:

Ah something new great! looking at the internal pictures on line there seems to be plenty of space in there.

All "one" of the internal pictures? Yep......... there's a LOT of space in there, the thing weighs in at 4.1 kilos and takes a day (exaggerating) to get into to then find..... a LOT of space

[vinylcharlie]

As the future proud owner of Mike's first M-1 HPA mod, I can't wait to get it back in my hands after the trip across the pond. From the look of the pictures of the board rework, it's got to sound awesome! I will report on sound improvement in about 10 days..

[vinylcharlie]

First night of listening report: I was extremely pleased right off the bat, ice cold, the amp produced a beautiful, lush, detailed sound that was thoroughly enjoyable. Just listening to FM on my Magnum Dynalab tuner, the amp drove my Grado GS1000 with ease and made the headphones sound much more musical sounding. Of course CDs and vinyl sounded even more immediate and captivating. Before the mod, I felt the sound of the M1 was somewhat veiled and a little strident. Now after Mike's rework of the board, it transformed the sound into more transparent, more musical and flowing, but at the same time more detailed. Instrument and voice sound stage placement sounds now more distinct and realistic. I have yet to try the USB DAC section, I will hopefully try that this weekend (Mike upgraded components in the DAC section as well).
Thanks Mike!

[PinkFloyd]

Hi Charlie,

I'm almost there with the computer, have reinstalled my photo software so will get the pics uploaded soon. Your M1 has had about 24 hours on it so allow it another 100 or so before expecting the very best from it..... from the "ice cold" get go it will sound a lot better but will continue to blossom as the caps form. I have tweaked the DAC section slightly to give you better volume pot range and I think you will like it I won't say any more until you've tried it.

Those 1 ohm wirewound resistors in the signal path were pretty much strangling the sound (think inductance) which is why I fitted the 1 ohm MILLS MRA5 non magnetic / non inductive ones..... they certainly did open things up a lot Charlie.

A lot more on this as soon as I get the computer up and running again...... I thought I had a "scrolling" virus so formatted the HD..... turned out it was the mouse that had developed a fault!!!!!

Still cannot believe they got that package from Edinburgh to the USA in a day??!!

[vinylcharlie]

Hi Mike, Now that I've been listening to this baby all weekend, the sound has gotten real sweet! The headphones sound even fuller with a real lush tone. i also managed to hood up my Galaxy phone via the "USB AUDIO PRO" app and streamed 16/44 FLAC files into the M1s dac section with great success. The USB input sounds very relaxing, very analog for a digital input. The bass sounds better than rca, it goes very deep and solid in usb mode. I'm sitting here just listening to a HD Radio station that sounds fantastic with the M1/ GS1000s. I don't know if you have hd radio in the UK, I know Canada does not broadcast it.
Loving this amp!

Charlie

[PinkFloyd]

Feb 26, 2017 23:00:32 GMT vinylcharlie said:

Hi Mike, Now that I've been listening to this baby all weekend, the sound has gotten real sweet! The headphones sound even fuller with a real lush tone. i also managed to hood up my Galaxy phone via the "USB AUDIO PRO" app and streamed 16/44 FLAC files into the M1s dac section with great success. The USB input sounds very relaxing, very analog for a digital input. The bass sounds better than rca, it goes very deep and solid in usb mode. I'm sitting here just listening to a HD Radio station that sounds fantastic with the M1/ GS1000s. I don't know if you have hd radio in the UK, I know Canada does not broadcast it.
Loving this amp!

Charlie

Hi Charlie,

THE DAC:

I'm glad you now like the DAC section, that was achieved by replacing the stock electrolytic small value caps with WIMA film caps and Nichicon MUSE non polar electrolytic caps. I cannot believe that MF used those god awful 1uF Jamicon electrolytics.... it clearly sounds so much better with the film caps / non polar caps!

Before (stock):



After:





Here is what I replaced:

C108 / C208 replace with 10uF / 16V Nichicon MUSE non polar capacitor

C26 replace with 47uF / 35V Panasonic NHG electrolytic

C16 / C17 / C22 / C23 / C24 replace with 1uF / 63V WIMA film cap

That will (as you have found) make the DAC section more analogue and natural sounding.


THE AMP SECTION:

Wirewound resistors in series with the output? What?! Think inductance here. MF fitted el cheapo 1 ohm wirewound resistors in series with the headphone socket (output) and, to my ears, these were absolutely strangling the sonics. I reached for my trusty stash of Mills MRA5 non inductive / non magnetic resistors and matched up two to a perfect 1 ohm:



Removed the two wirewound resistors:



And then fitted the two matched Mills MRA5 1 ohm non magnetic / non inductive resistors:



BIG improvement.... a definite veil lifted for sure, a lot more macro detail / minutiae coming through (as I expected would be the case).

Next up were the output coupling capacitors..... MF fit 2 x 470uF per channel (in parallel) making a total of 940uF per channel. I wonder why they fit TWO per channel (in parallel) when 1 x 1000uF is all that is required and one instead of two capacitors in the signal path always sounds best...... less equates to more when it comes to capacitors in the signal path. MF probably have a shed load of 470uF in stock so they prefer to use them (2 x in parallel to make 940uF) rather than bin them and purchase 1000uF non polar caps. Anyhoo....... another most noticeable improvement in SQ removing the penny a pop Jamicons and replacing with 2 x 1000uF / 6.3V Nichicon MUSE non polars.

Before:



1000uF Nichicon MUSE non polars in situ:





The rest of the tweaks, I want to hold close to my chest for the time being but here is a before and after photo:

Before:



After:



Here are a few under the bonnet snaps of the modded amp:















If you want to DIY here are the details for the amp section:

Remove C110 / C111 / C210 and C211. Fit 1000uF 6.3V Nichicon MUSE non polar to C111 / C211

Remove R114 / R214. Fit Mills MRA5 1 ohm (5 watts)

C112 / C212 Fit 1uF / 63V WIMA film cap

C106 / C206 fit 10uF Nichicon MUSE non polar 16V OR jumper over the pads if there is zero DC on the source output.

C104 / C105 / C204 / C205 Remove and replace with 100uF / 35V ELNA Silmic ll (Japanese silk fiber) capacitors.

All the best,

Mike.

[vinylcharlie]

Mike, Thanks for all the detailed pictures, very nice, neat work. You would think that MF would be able to more or less improve the same parts that you did and offer a "special edition" version of the amp that would probably easily sell for a much higher price and be super profitable for them.
I can attest to the fact that you have brought this amp up to whole new level, it is seriously now a piece of "High Fidelity" equipment!
That last picture of the amp with your Northern Scottish landscape in the background looks very handsome indeed!

[vinylcharlie]

Hi Mike,

A couple of weeks ago I picked up a Magnum Dynalab MD-205 "signal sleuth" that helps amplify and isolate specific fm frequencies. It does really help me tune in difficult stations but.....I have weird kind of Radio (RFI) interference that happens when I turn the power on to the M1HPA. It almost totally cancels out the signal strength of a station. There is an analog signal strength meters on my MD102T tuner and when the M1HPA is turned at the same time as the MD-205 signal sleuth, the signal strength meter drops right down and the station is lost. Is the switching power supply on the M1 generating some type of RFI. What do you suggest to bypass this interference? thanks!
Regards,
Charlie

[freddypipsqueek]

Charlie.

Some DACs give off alot of RFI - my Black Box 2 has a poor reputation in that respect. The Meridian 104 I use is OK but the Arcam tuner is 4 feet away from the DAC and for both the siugnal booster is in the roof 20 ffets away. It is unlikely to be the switching power supply but something from the DAC which your signal amplifier picks up on. Move the Magnum away - it should (I suspect but do not know for sure) be close to the aerial itself - if need be try alot of coax (if you have it spare) and move it into another room or out of the room particularly if a modern house with lined plasterboard (which will act as a faraday cage - which can be good or bad) - and see how you go. It may be a case of a couple of feet apart . . .

A.

[vinylcharlie]

Hi Mike, Here's an update on my fm reception issue and how I solved it. I have an aerial antenna on the roof of my house, so I went up to the chimney where the antenna is attached and fiddled a bit with the connections. I disconnected and reconnected the 75 ohm cable to the splitter and when I got down, reception on my hard to get station became rock solid. So I am taking out the MD signal booster which really did not like the M1HPA. Then listen to this, I was fooling around late last night and hooked up the M1 directly to my desktop computer's usb jack...WOW!, the sound was incredible. I already had a small usb headphone amp hooked up to the computer, a Audinst HUB Mx2 and the Musical Fidelity amp trounced it in every way! I was using my Grado 325 headphones and the musical presence with M1 was so powerful, smooth and engaging, that's where the baby is staying. This sounds so good I think since you reworked the USB section so well. So thanks again for the great work, I think I will enjoy the amp so much more now in it's new computer based setting.
Hope all is well,

Regards,
Charlie

[PinkFloyd]

Jun 7, 2017 16:26:10 GMT vinylcharlie said:

Hi Mike, Here's an update on my fm reception issue and how I solved it. I have an aerial antenna on the roof of my house, so I went up to the chimney where the antenna is attached and fiddled a bit with the connections. I disconnected and reconnected the 75 ohm cable to the splitter and when I got down, reception on my hard to get station became rock solid. So I am taking out the MD signal booster which really did not like the M1HPA. Then listen to this, I was fooling around late last night and hooked up the M1 directly to my desktop computer's usb jack...WOW!, the sound was incredible. I already had a small usb headphone amp hooked up to the computer, a Audinst HUB Mx2 and the Musical Fidelity amp trounced it in every way! I was using my Grado 325 headphones and the musical presence with M1 was so powerful, smooth and engaging, that's where the baby is staying. This sounds so good I think since you reworked the USB section so well. So thanks again for the great work, I think I will enjoy the amp so much more now in it's new computer based setting.
Hope all is well,

Regards,
Charlie

Hi Charlie,

Good to hear from you again, sorry I'm late to the party replying but have not had a lot of spare time of late. Adrian's (Freddypipsqueek) advice was good advice but it seems you have managed to sort it out. When I was working on your M1 I had radio 2 on in the background (FM / Old school radio) but the moment I fired your M1 up to listen to it all I got from Radio 2 was a hiss...... definite RFI coming from the M1 and it was obviously being generated from the switched mode power supply inside the M1.

Anyhoo....... I turned my FM tuner off, bolted your M1 board back into the enclosure, turned the tuner back on and it was a LOT better BUT I could still detect RFI from the M1 SMPS power supply reaching my FM tuner..... nowhere near as bad but bad because it was interfering with my tuner!

I clamped a snap on ferrite core onto the mains lead of the FM tuner and all was normal again...... it was similar to one of these: uk.farnell.com/tdk/zcat1730-0730a-bk/ferrite-core-split-4-7mm-50-ohm/dp/2364655?mckv=_dc|pcrid|78108292749|&gross_price=true&CATCI=pla-141995803989&CAAGID=14989786509&CMP=KNC-GUK-GEN-SHOPPING-TDK&CAGPSPN=pla&gclid=CNue9JfJrNQCFViRGwodQboC1w&DM_PersistentCookieCreated=true&CAWELAID=120173390001372749

A simple fix and always the first I try...... works 95% of the time.

SMPS and old school FM tuners don't really get on well together (neither do Mobile phones and old school FM tuners)...... I won't go round the mulberry bush explaining the why and how of why this is sometimes the case but WILL, quite simply, say that a snap on ferrite core is your best friend in situations like this.

I have got loads of them kicking about and more than happy to send you one FOC.

Best place to position it is on the mains lead, nearest to the mains input socket to the FM tuner...... does the job.

Glad you like the DAC section of the M1 Charlie..... I have now worked on quite a few of them and so happy I got that one right The feedback has been tremendous and just what you and I heard........ "analogue like".

Remind me of your details Charlie and I'll ship a mama honker Ferrite clamp over to you

All the best from rainy Scotland,

Mike.

[PinkFloyd]

22nd April 2018 - Ian Milligan's M1 HPA

Pretty much the same as Charlie's amp apart from using Ohmite Audio Gold resistors (instead of Mills MRA5) on the output.

The Ohmite Audio Gold resistors have grown on me...... time after time I find myself preferring they were in a circuit rather than out....... they don't seem to get a lot of press but, believe me, they are good........ use your ears



I went with the same parts I used for Charlie's amp in the DAC section... replaced the 1uF electrolytics with 1uF WINA film caps, replaced the 10uF el cheapo non polar electrolytics with Nichicon MUSE non polar and replaced the nasty Jamicon SK with a silk fiber (Japanese) ELNA Silmicll. Simple as that, the DAC now sounds more analogue........



These amps are a pain with regard to getting the board out..... it's screw city / so many screws and hidden entries BUT (when you do enter the inner sanctum) it looks like this:



All good but not an easy access amp..... the through hole pads and use of unleaded solder make it a bugger to work on.

It's for that reason I have never got round to supplying a kit for the M1 HPA.......... I can get into them and mod them but they are not "easy" to work on...... the solder MF have used in them is like concrete (lead free gone wrong!) .... my Weller @ 450C was finding it hard to melt that crap..... I had to flood in (to EVERY solder joint) some 60/40 before desoldering, that was the only way the unleaded solder would pool (become liquid).

Anyhoo....... here it is.... sounding gorgeous!

[bixby]

Gents, new member here and owner of the MF M1HPA headphone amp. While I like it as an amp, it sounds a bit glarey in the upper mids, lower treble and is a bit muffled as my son calls it in the midrange. I like the sense of space and nice warmth on the low end. Highs are smooth and perhaps a bit laid back on my setup with Senn 600s.

And that is why I am here. I have had lots of flavor of the month amps through my house over the past decade. I am intrigued with the mods offered by PinkFloyd. I will probably have my amp builder buddy do them with me as a third or fourth hand. I would appreciate any thoughts or experience on a few questions below.

1. Do you feel the mods will alleviate some or most of the glare I perceive? I read that the minute details and clarity open up with the mods so hoping the glare goes away.

2. This maybe a dumb one but the resistor and cap mods on the headphone output look to be a dual path? Is that for left and right channel or is it two separate paths to the two separate headphone jacks? My thought here was if is was two separate paths, could one use a different resistor for one side vs the other and hear slight differences depending on HP jack?

thanks in advance for any help or thoughts.

cheers