Modding my ARC Ref Anniversary

[sbo6]

It's not a matter of labeling the caps incorrectly, but rather to identify the typical variance of the lot (typically in the hundreds or thousands for a manufacturing run). Put simply, for a given lot, caps are labeled with their mean value and standard deviation. It's up to the engineer to decide what value is appropriate for their specific application and to select or reject accordingly.

Many years ago, I visited John Dunlavy at his company in Colorado because I admired his crossover design (published openly) and questioned him about part of the circuit I didn't understand, He brought me into the factory and took me to the bench where the tech was assigned to measure the capacitance value precisely of a particular part of the circuit and then adjust that value according to a 1% tolerance since the published cap values were inadequate for his needs. He said that it was critical for the time alignment and superb impulse measurements his speakers were famous for. But that key sub-circuit's precision, he said, was not necessary in other parts of the circuit. Then, we went out to dinner, where he got so smashed that the next day he totally forgot what he showed me the previous day in the factory. He was a giant of an audio engineer who I admired very much because of his transparency, but man, that guy could drink like a fish.

Thanks for your reply and a good story, I got a laugh out of the end

I get your point and know about component manufacturing quality sampling etc. The cap tolerance and accuracy as labeled importance depends on the circuit design and application as you suggested. Not disagreeing just stating a bit differently.

 

[Barry]

Interesting thread. Everyone seems to have their own experience and opinions, as expected. I've been modifying equipment for 50 years and have spent way, way more on parts than what a REF 40 retailed for, $8K on one recent project alone. I can really relate most to everything that Marty says.

I have learned to appreciate what manufacturers do to voice their equipment and build to a price point. It's not easy. Modifying anything that's well designed and built is such a painstakingly recursive process that only a masochist with the patience of Job is assured of consistent success. Oh, and if you're really good at it, or really bad(!); most circuit boards will give up long before you do!

 

[marty]

Modders, this could be your lucky day. As I said, my modding days are long over but I have ton of parts that I will never use again. Here are some assorted Caddock 311 power resistors resistors. All were custom ordered for various speaker crossover projects. 1% tolerance. A few thousand bucks here. I'm happy to give them to anyone who would give them a good home, for the cost of postage. I found these the finest sounding, low noise power resistors on the planet. I started using them years before they were original equipment in Wilson speakers. Caddock is now owned by Vishay. PM me if interested.

 

[Phillyb]

I owned ARC 30 years ago, they kept coming out with newly upgraded units every 6 months its seemed, so the money just spent was no longer holding any value, then another upgraded unit on top of that my preamp when looked at by my tube lover who grew up with tubes and new designs inside out, said geez there is so much unneeded stuff in this unit that hurts the sound let me look at it and I'll get back to you, he called me on changes of subtraction of parts, no mods just simplified the circuit design, and wow, night and day better, much, later on, he built his own preamp with an outboard power supply to boot and it smoked the arc preamp, the SP3A. I never looked at the ownership of ARC products again. So many good tube amps out there and they keep products a long time, not upgraded unit after unit. It's good marketing but also hurts the consumer. I look inside of the preamps, and some I shake my head for what they ask, and what you see inside of them makes no sense. The EV0 400 preamp is better built and better quality parts than many of ARC preamp, and it sounds wonderful. $4,500 preamp. I like the ARC Reference model 6 preamp, but for $14,000 I just don't see the value in it, or sonically better than an EVO 400 overall. IMHO.

 

[Joostp]

David, thanks a lot for a new idea! I've PMed you on this.

My engineer has left and the system is up and running again. What I'm hearing brings me to an inevitable conclusion: quality of resistors (and diodes) in audio electronics is as important as capacitors. Very glad I did it! Low-end resolution and articulation is much better. Top end is silky-smooth. Tonal richness is better. Sound stage is deeper and the background is darker. I am bracing myself for a long a bumpy break-in period. Not the first time though. Must be brave;-)

P.S. The magnetic crap my engineer soldered out is already in the trash can. Amen.

I was also inspired and replaced most of the resistors in my ARC LS27 a week ago.
Could you tell me a bit more on how the break-in period for the resistors progressed?

 

[ayreman]

We

I was also inspired and replaced most of the resistors in my ARC LS27 a week ago.
Could you tell me a bit more on how the break-in period for the resistors progressed?

Well, it ain't over yet. The sound alternates between harsh top end and boomy base and silky-smooth top and very deep and articulate low end. Couple of days the "pendulum" is stuck one way, then it swings the other way. Recently the frequency of changes has intensified and when it is good - it is indescribably good. The black, the soundstage depth are utterly uncanny.

Nice to see the VARs on your PCB. But those Mundorf MCap EVOs don't belong there. They are a very modest improvement over the stock ARC caps you soldered out. I know the space there is limited. But you don't necessarily need 10 uF there. Far from it. You really want copper foil caps in there. It's day and night difference. Audyn True Copper Max or, better still, Duelund JDM Copper Foil are very affordable. Add to those 0.01 Duelund JDM Silver Foil bypasses underneath the PCB and your LS27 will outperform ARC Ref 10 in stock.

Last but not least, I would get rid of those red WIMAs. Their top end is harsh and irritating. What a relief I felt when I threw mine out!

You've made a good start. Don't stop at that if you like our hobby!;-)

 

[trekpilot]

Ayreman,
What caps do you recommend using to replace the Wimas?

Thanks,
Scott

 

[DasguteOhr]

PS after modding (top view):
1. All Nichicon electrolytic caps were raplaced with Mundordf, Audio Note (including Kaisei), Jensen and Elna Silmic II.
2. 100% of REL-CAP and 95% of Wima were replaced with Audyn True Copper Max, Jupiter Copper Foil and Duelund Tinned Copper Foil Precision.
3. All the wiring was done with AQ PSC+ solid-core conductors extracted from AQ NRG 1.5 power cables.
4. All soldering was done with AQ silver solder.
5. Factory power inlet and fuse holder were replaced with Furutech FI-33 NCF and Soviet military copper fuse holder with silver plating.

Really good choice Audyn True Copper, i think you will have a lot of fun
with that Mod.
They need some days to come alive.

 

[Joostp]

We

Well, it ain't over yet. The sound alternates between harsh top end and boomy base and silky-smooth top and very deep and articulate low end. Couple of days the "pendulum" is stuck one way, then it swings the other way. Recently the frequency of changes has intensified and when it is good - it is indescribably good. The black, the soundstage depth are utterly uncanny.

Nice to see the VARs on your PCB. But those Mundorf MCap EVOs don't belong there. They are a very modest improvement over the stock ARC caps you soldered out. I know the space there is limited. But you don't necessarily need 10 uF there. Far from it. You really want copper foil caps in there. It's day and night difference. Audyn True Copper Max or, better still, Duelund JDM Copper Foil are very affordable. Add to those 0.01 Duelund JDM Silver Foil bypasses underneath the PCB and your LS27 will outperform ARC Ref 10 in stock.

Last but not least, I would get rid of those red WIMAs. Their top end is harsh and irritating. What a relief I felt when I threw mine out!

You've made a good start. Don't stop at that if you like our hobby!;-)

The EVO's was one of the first mods i did not wanted to change any values then.
I believe that with my REF75 power amp a coupling cap 0.33 uF is sufficient and a Copper Max in that capacity would fit easily.
I am not (yet) ready to start replacing Wima's, maybe in few months. Keep us posted on how the break-in goes.

 

[ayreman]

Ayreman,
What caps do you recommend using to replace the Wimas?

Thanks,
Scott

I always recommend what I've used myself because I guarantee the good result. 0.47 uF True Copper Max replaced all the WIMAs. They won't fit on top of the PCB, of course. But underneath - there's plenty of room and you can use a good quality sticky (on both sides) tape to firmly secure them in place. Forget the film caps. Always use copper foil!

 

[ayreman]

I believe that with my REF75 power amp a coupling cap 0.33 uF is sufficient and a Copper Max in that capacity would fit easily.

Very good plan. But be sure to bypass each of the 4 True Copper Maxes with 0.01 Duelund JDM Silver Foil caps:

Duelund Capacitor 0.01uF 600Vdc JDM-Ag Series Silver Foil Wax Paper Oil

Duelund 0.01uF 600Vdc JDM Series Silver Foil & Wax/Oil Precision Capacitor If you want a hi-fi setup with spatialized audio and life-like reproduction, Duelund has you covered. The NEW JDM Silver Bypass Capacitor features oil impregnation along with a pure silver foil, making it the top choice...

www.partsconnexion.com

You won't believe what this tandem can do. Simply marvelous! And very affordable too... On the attached photo you see the older version which cost me an arm and a leg. You are lucky because the new JDM version is much, much cheaper and every bit as good;-).

 

[Joostp]

I got hold of some 0,56 uF Copper max caps for my LS27. Size was a problem so i had to install them upright.
It is a step forward compared to the 10uF Mundorf Evo's i had in there which souned a bit bright

Before i installed them i used my new 'break-in device' (courtesy of hificollective.co.uk) to treat them to some 80 hours of music.

I also noted a 1uF bypass cap (next to the red Wima's) that looked odd and it turned out to be broken so i replaced all the 1uF caps with Elna Silmic's.

Next week a friend will bring his unmodified ARC LS28 for comparison and i am very curious for the result.

 

[ayreman]

I got hold of some 0,56 uF Copper max caps for my LS27. Size was a problem so i had to install them upright.
It is a step forward compared to the 10uF Mundorf Evo's i had in there which souned a bit bright

Before i installed them i used my new 'break-in device' (courtesy of hificollective.co.uk) to treat them to some 80 hours of music.

I also noted a 1uF bypass cap (next to the red Wima's) that looked odd and it turned out to be broken so i replaced all the 1uF caps with Elna Silmic's.

Next week a friend will bring his unmodified ARC LS28 for comparison and i am very curious for the result.

Well done, Joostp! I don't envy your friend He will be very envious...

I won't sleep well till you bypass your 0,56 uF Copper Max caps with these:

JDM-AG-010: 0.01uF 600Vdc Duelund JDM Pure Silver Foil Capacitor | HIFICollective

JDM-AG-010: 0.01uF 600Vdc Duelund JDM Pure Silver Foil Capacitor

www.hificollective.co.uk

It's only $200 bucks! And you can piggyback them onto the Copper Maxes easily because they are tiny. Ah, they are so damn good they are worth $100 each!

Here's one last idea and I will leave you to your music: replace those large Nichicon electrolytic caps (470 uF, if I'm not mistaken) with Mudorf 680 uF. I did exactly the same in my PS unit (see attached pics) and I love 'em! The more capacitance - the better. Here they are:

MLGO450-680: 680uF 450Vdc Mundorf MLytic HV Radial Electrolytic Capacitor | HIFICollective

MLGO450-680: 680uF 450Vdc Mundorf MLytic HV Radial Electrolytic Capacitor

www.hificollective.co.uk

 

[Cellcbern]

PS after modding (top view):
1. All Nichicon electrolytic caps were raplaced with Mundordf, Audio Note (including Kaisei), Jensen and Elna Silmic II.
2. 100% of REL-CAP and 95% of Wima were replaced with Audyn True Copper Max, Jupiter Copper Foil and Duelund Tinned Copper Foil Precision.
3. All the wiring was done with AQ PSC+ solid-core conductors extracted from AQ NRG 1.5 power cables.
4. All soldering was done with AQ silver solder.
5. Factory power inlet and fuse holder were replaced with Furutech FI-33 NCF and Soviet military copper fuse holder with silver plating.

Amazing isn't it how even expensive, famous brand components will be filled with cheap caps, resistors, etc - a result of designing to a price point. My similar upgrading of my Pathos TT RR is described in my posts at this forum. At this point every component in my system including my speakers has been modified to include "world's best" parts and hookup wire. The huge caps in the "2020 mods" photo are Dueland Cast PIO Tinned Copper Foil. Note that the addition of Bybee Music Rails in both my Pathos and Unison amps and my Modwright-modified Marantz sacd player resulted in a significant reduction in noise. I've also had very good results with the Stage III Concepts hookup wire. Note that the 2011 mods (2nd photo) were done by Nick Doshi (who used to be an official Pathos repair tech) long before he became a leading high end manufacturer. My tech and I consulted with the Pathos factory on the 2020 mods to make sure we didn't do anything counterproductive. To my surprise they gave advice and suggestions and shared some things that they had tested but were "too expensive to put into production".

Can you give me the source for the fuse holders?

FYI: https://www.whatsbestforum.com/threads/modified-upgraded-pathos-tt-rr.32257/#post-705191

 

[Cellcbern]

PS after modding (top view):
1. All Nichicon electrolytic caps were raplaced with Mundordf, Audio Note (including Kaisei), Jensen and Elna Silmic II.
2. 100% of REL-CAP and 95% of Wima were replaced with Audyn True Copper Max, Jupiter Copper Foil and Duelund Tinned Copper Foil Precision.
3. All the wiring was done with AQ PSC+ solid-core conductors extracted from AQ NRG 1.5 power cables.
4. All soldering was done with AQ silver solder.
5. Factory power inlet and fuse holder were replaced with Furutech FI-33 NCF and Soviet military copper fuse holder with silver plating.

Can you give me the source of the fuse holders?

 

[audioguy1958]

To answer your questions... Yes, cap mods were done in stages. Many stages indeed. The first coupling caps I used (for about a year) were Mundorf Supreme SGO. Then I tried Audyns and realised film can not compete with foil. Ended up using CAST Silver Foil Duelunds as my main coupling caps, which I first bypassed with Audyns and 0.01uF precision Duelunds. Eventually, I replaced the Audyns in that position with the Jupiters. That trio will stay there for ever. Splendid! Remove CAST Duelunds and we've lost top end agility and liveliness. Remove the Jupiters - and we've lost fabulous mid range. Top copper and silver foil really complement each other well.

No more comparisons will be done in my system. Stock gear does not excite me any more. With any price tag. These days I prefer to enjoy what I have here...

Cost of mods... I never kept any financial records. You can see it all on the pics. Just grab a calculator and do your maths. I never cared what it cost because I am addicted to best

I find attempts to describe the sound futile. Words are pretty much meaningless because everyone will interpret those words based on his own scale of reference. All I can say is that resolution has gone up tenfold. The sound is natural, organic and utterly addictive. Music plays here, right in front of my nose, not there in a distance and I find it very hard to stop listening to it. Taking vacations is a problem. 3 days go by and I already want to go home to listen to some music. I sopped attending live concerts with amplification. Everything here sounds so much better...

I've had all my equipment modded with better electrical parts, Mundorf and Audio Note amongst others. The difference in sound quality is astounding. I have to wonder if spending hundreds of thousands of dollars on much of what's considered the best equipment is more about ego than sound quality.

I'm interested in your comment regarding Mundorf classic Silver/Gold/Oil versus Audyn, you really found the Audyn significantly better? The TOTL Mundorfs are remarkable as it is.

 

[audioguy1958]

We

Well, it ain't over yet. The sound alternates between harsh top end and boomy base and silky-smooth top and very deep and articulate low end. Couple of days the "pendulum" is stuck one way, then it swings the other way. Recently the frequency of changes has intensified and when it is good - it is indescribably good. The black, the soundstage depth are utterly uncanny.

Nice to see the VARs on your PCB. But those Mundorf MCap EVOs don't belong there. They are a very modest improvement over the stock ARC caps you soldered out. I know the space there is limited. But you don't necessarily need 10 uF there. Far from it. You really want copper foil caps in there. It's day and night difference. Audyn True Copper Max or, better still, Duelund JDM Copper Foil are very affordable. Add to those 0.01 Duelund JDM Silver Foil bypasses underneath the PCB and your LS27 will outperform ARC Ref 10 in stock.

Last but not least, I would get rid of those red WIMAs. Their top end is harsh and irritating. What a relief I felt when I threw mine out!

You've made a good start. Don't stop at that if you like our hobby!;-)

Don't forget that replacing capacitors requires a long burn in process during which the sound will change several times. The final sound is not at all like the beginning of burn in. I've found that electrolytics need at least 300 hours of burn in and film and oil caps at least 50 hours, more is better.

 

[Cellcbern]

Don't forget that replacing capacitors requires a long burn in process during which the sound will change several times. The final sound is not at all like the beginning of burn in. I've found that electrolytics need at least 300 hours of burn in and film and oil caps at least 50 hours, more is better.

I'm 500+ hours in and it sounds glorious - in my small listening room and within its 35w/ch limitation, as good as the Vinnie Ross L2i and any of the six figure separates I listened to at the last Capital Audiofest. Can you tell me where you got the silver plated Soviet military fuse holders?

 

[justubes]

That most beautifully done up quality mods i have seen!

Could you share more on what the stage III hook up wire brought comparatively, please?

 

[Cellcbern]

That most beautifully done up quality mods i have seen!

Could you share more on what the stage III hook up wire brought comparatively, please?

Bill Thalman at Music Technology, Inc. in Springfield, VA does incredible work. I have no way to attribute specific aspects of the improvement in sound quality to the Stage III hookup wire vs. the Dueland caps vs. the Bybee Music rails, etc. Too many things were changed, and just about every aspect of the amp is improved. All of the wiring in the signal path (all of the white wires in the photo of the stock Pathos TT that I posted) was silver in the stock amp, so I looked for a superior silver wire to replace it with. I chose the Stage III because of the unique spiral conductor which gets it very close to an air dielectric. I had also listened to several different Stage III cables and was impressed with the sound quality. Note that reviews of the stock amp described it as a little polite and subjectively not the fastest. There is an increase in speed and dynamics with the mods that goes beyond what I expected to hear based on previously modified components (e.g., Bill Thalman used the Dueland tinned copper wire in his modification of my Unison S6). I thought the Stage III Concepts wire might be at least partially responsible for this but again I have no way to prove it.