Ultimate Aragon 18K Rebuild

Dr K said:
Hi, I love the sound of Viva gear! I almost bought one of their amps 8 years ago, but I needed more power. Beautiful gorgeous sound, though.

The modded 18K I have sounds nothing like a stock or lightly modded 18K. It's in another class. The underlying 18k is very well designed and elegant, other than the input coupling caps. I prefer simple elegant circuits (e.g., most Tube amps/preamps, Pass Aleph and First Watt) over the complex (Mark Levinson, Krell). I've auditioned very well known $10k+ preamps, and my 18K competes with them and in certain respects surpasses them (transparency and high frequency performance). I moved to passive preamps about 7 years ago because I found property set up passives (proper impedance matching and short cable lengths) to my ears are better than most active preamps out there regardless of cost. However, my recent foray into modding Mondial designed preamps have changed my views about affordable active preamps.

The great thing about this project was the relative pittance in cost in upgrading the 18K compared to moving up to a higher class $10K preamp with similar performance. Even $10k+ preamps do not use type of parts used in my 18K because they would to considered too expensive or exotic. However, my ultimate dream active preamp would be the Dartzeel NHB-18NS or Ayer KXR Twenty. These are truly cost no object preamps in my book, but come at a cost ($27k+). If I hit the lotto...
Click to expand...

I certainly would hope your 18K is performing well outside of the class of a "lightly" modded unit to your ears. Everyone has their own approach to achieving the sound they want. what's "Better or BEST" is truly subjective. The concept of DIY or modding offers some advantages over "AUDIOPHILE" gear in parts selection , circuit design, layout or even just pure satisfaction of having involvement in what went into the making of the unit. I'm certainly of the mindset that Just because something is expensive doesn't mean it will outperform a custom built, or Modified unit. but at the same time, one could also go into a Mod project and find that the result doesn't offer more of a sonic improvement over something that is stock ( that was my point- more cautionary in the belief that MODDED automatically means sonically better. subjectivity will again have a hand in the determination) and that determination is on the end user and his or her assessment. Not every mod will result in a holy grail, I've been to the mountain top experience. Just like not every $10K+ expensive or exotic component will offer that experience ( same could be said for parts of a similar distinction). I've heard plenty of "craptastic" high end systems and had the thought, that a simple "off the rack" sytem sounded better to me. for someone else it may have been the best thing they've ever heard in their life.

I've owned plenty of cost effective components by lesser known manufacturers, DIY builders, and even a few home grown units from some legendary old school guys that for "my taste", outperformed some fairly hyped well known units. I still use those components today. In your case, you put your thoughts into this project, specified where you wanted to make changes and what components you wanted to use based on what satisfied your desires with regards to expected outcome. Reading through your follow up , it sounds like you are very happy with the results and with the exception of the balance issue, it all worked out well for you. Congrats. It may be a path that others will attempt to go down as well and I hope that they are as equally satisfied with the outcome. I'm sure for some ( possibly even many) will be VERY satisfied in the performance of their rebuilt Aragon unit. Some may have a different experience.

Great build, and again Congrats to you. It was nice seeing the process that you took in achieving the sound and experience you wanted for yourself. I'm looking forward to the additional pics and long term insights. Certainly not your run of the mill Aragon 18K by any stretch :)
 
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Bostown said:
I certainly would hope your 18K is performing well outside of the class of a "lightly" modded unit to your ears. Everyone has their own approach to achieving the sound they want. what's "Better or BEST" is truly subjective. The concept of DIY or modding offers some advantages over "AUDIOPHILE" gear in parts selection , circuit design, layout or even just pure satisfaction of having involvement in what went into the making of the unit. I'm certainly of the mindset that Just because something is expensive doesn't mean it will outperform a custom built, or Modified unit. but at the same time, one could also go into a Mod project and find that the result doesn't offer more of a sonic improvement over something that is stock ( that was my point- more cautionary in the belief that MODDED automatically means sonically better. subjectivity will again have a hand in the determination) and that determination is on the end user and his or her assessment. Not every mod will result in a holy grail, I've been to the mountain top experience. Just like not every $10K+ expensive or exotic component will offer that experience ( same could be said for parts of a similar distinction). I've heard plenty of "craptastic" high end systems and had the thought, that a simple "off the rack" sytem sounded better to me. for someone else it may have been the best thing they've ever heard in their life.

I've owned plenty of cost effective components by lesser known manufacturers, DIY builders, and even a few home grown units from some legendary old school guys that for "my taste", outperformed some fairly hyped well known units. I still use those components today. In your case, you put your thoughts into this project, specified where you wanted to make changes and what components you wanted to use based on what satisfied your desires with regards to expected outcome. Reading through your follow up , it sounds like you are very happy with the results and with the exception of the balance issue, it all worked out well for you. Congrats. It may be a path that others will attempt to go down as well and I hope that they are as equally satisfied with the outcome. I'm sure for some ( possibly even many) will be VERY satisfied in the performance of their rebuilt Aragon unit. Some may have a different experience.

Great build, and again Congrats to you. It was nice seeing the process that you took in achieving the sound and experience you wanted for yourself. I'm looking forward to the additional pics and long term insights. Certainly not your run of the mill Aragon 18K by any stretch :)
Click to expand...


Thanks for feedback. I agree that no one should consider any subjective review as absolute and will have the same experience. I have my own personal tastes in sound and music that may not suit others.
 
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Hmm...am I going crazy? I can't seem to insert photos. When I click on the "image" icon, it asks for image URL. It doesn't allow me to search my computer for the photos. Help?
 
Dr K said:
Hmm...am I going crazy? I can't seem to insert photos. When I click on the "image" icon, it asks for image URL. It doesn't allow me to search my computer for the photos. Help?
Click to expand...

Never mind. I'm getting old. Here are the photos. My rebuilt 18K is on the bottom rack with its power supply on the left. The tubed unit on the floor is Don Sachs preamp. The Tortuga Audio passive LDR preamp with its batter power supply is on the upper rack on the left next to the Lampizator Golden Gate DAC. My music server is Mac Mini based server from dB Audio Labs (extensively reworked with new hardware and rewritten OS code for audio playback) and also has a battery power supply.

You can see overview of my audio room with the Bob Carver's tube mono block amps and Raidho D2.1 speakers. There are acoustic absorber panels in front of the speakers on the floor to absorb floor bounce which helps to improve midrange and upper bass clarity. The speakers sit on Townsend Audio speaker Podiums (hard to see in the photos), which is the best isolation platform I've found for speakers.
 

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Serious stuff, Dr. K.

Congrats, brother. The wife bought me some acoustic panels for Xmas, so it is time to get serious, like you.
 
Bostown said:
I certainly would hope your 18K is performing well outside of the class of a "lightly" modded unit to your ears. Everyone has their own approach to achieving the sound they want. what's "Better or BEST" is truly subjective. The concept of DIY or modding offers some advantages over "AUDIOPHILE" gear in parts selection , circuit design, layout or even just pure satisfaction of having involvement in what went into the making of the unit. I'm certainly of the mindset that Just because something is expensive doesn't mean it will outperform a custom built, or Modified unit. but at the same time, one could also go into a Mod project and find that the result doesn't offer more of a sonic improvement over something that is stock ( that was my point- more cautionary in the belief that MODDED automatically means sonically better. subjectivity will again have a hand in the determination) and that determination is on the end user and his or her assessment. Not every mod will result in a holy grail, I've been to the mountain top experience. Just like not every $10K+ expensive or exotic component will offer that experience ( same could be said for parts of a similar distinction). I've heard plenty of "craptastic" high end systems and had the thought, that a simple "off the rack" sytem sounded better to me. for someone else it may have been the best thing they've ever heard in their life.

I've owned plenty of cost effective components by lesser known manufacturers, DIY builders, and even a few home grown units from some legendary old school guys that for "my taste", outperformed some fairly hyped well known units. I still use those components today. In your case, you put your thoughts into this project, specified where you wanted to make changes and what components you wanted to use based on what satisfied your desires with regards to expected outcome. Reading through your follow up , it sounds like you are very happy with the results and with the exception of the balance issue, it all worked out well for you. Congrats. It may be a path that others will attempt to go down as well and I hope that they are as equally satisfied with the outcome. I'm sure for some ( possibly even many) will be VERY satisfied in the performance of their rebuilt Aragon unit. Some may have a different experience.

Great build, and again Congrats to you. It was nice seeing the process that you took in achieving the sound and experience you wanted for yourself. I'm looking forward to the additional pics and long term insights. Certainly not your run of the mill Aragon 18K by any stretch :)
Click to expand...

In the same vein as this I have to comment that I see a lot of questions here on AK like "What will I hear if I upgrade to component X or if I upgrade component X with these parts?" Many folks don't realize the problem with this question. There are so many variables between one persons listening space and anothers i.e., room dimensions & volume, acoustic treatments, acoustically absorptive or reflective furniture items. Not to mention the state of ones hearing as my 52 yr old ears may have a marked roll-off where someone who's 25 years younger likely does not, so something I find acceptably extended in frequency response they may find to be too hot on the top end. Then there's the speakers, which are usually the biggest "knob" in ones system, changing the speakers is generally the biggest change to sound most people will make. So my telling you what I hear on say my Acoustat's is generally going to be markedly different than your experience on a pair of Altec's, Infinity RS, Apogee's, etc... Its nearly impossible to predict what another person will hear with a specific component or upgrade due to all of the variables.

It also drives me nuts to look at an equipment manufacturer's website or literature and see statements about improvement's you'll hear over their previous components. Some manufacturers are wise enough to make more general comments like, "Owners typically report improvements to .....". Personally I'd question anyone that tells you what YOU ARE going to hear. To me that's more snake oil than fact. I do like those manufacturers that stick to the technical merits of changes to their gear.
 
mondialfan said:
In the same vein as this I have to comment that I see a lot of questions here on AK like "What will I hear if I upgrade to component X or if I upgrade component X with these parts?" Many folks don't realize the problem with this question. There are so many variables between one persons listening space and anothers i.e., room dimensions & volume, acoustic treatments, acoustically absorptive or reflective furniture items. Not to mention the state of ones hearing as my 52 yr old ears may have a marked roll-off where someone who's 25 years younger likely does not, so something I find acceptably extended in frequency response they may find to be too hot on the top end. Then there's the speakers, which are usually the biggest "knob" in ones system, changing the speakers is generally the biggest change to sound most people will make. So my telling you what I hear on say my Acoustat's is generally going to be markedly different than your experience on a pair of Altec's, Infinity RS, Apogee's, etc... Its nearly impossible to predict what another person will hear with a specific component or upgrade due to all of the variables.

It also drives me nuts to look at an equipment manufacturer's website or literature and see statements about improvement's you'll hear over their previous components. Some manufacturers are wise enough to make more general comments like, "Owners typically report improvements to .....". Personally I'd question anyone that tells you what YOU ARE going to hear. To me that's more snake oil than fact. I do like those manufacturers that stick to the technical merits of changes to their gear.
Click to expand...

Hi Kevin, thanks for chiming in. I agree wholeheartedly. A subjective review is just that subjective, no matter who the reviewer is. I made that mistake when I first got into highend back in the early 80's, and 80% of the time came away disappointed when the component didn't live up to the hype. My review of my modded 18K is valid in my system, and perhaps yours, as we have described similar findings, but in someone else's system with bright electronics or speakers, my 18K may be too much.

Btw, the soundstage keeps on improving. In some recordings, the soundstage is huge. Most of all, I enjoy my music more than ever before. This is the best investment I've ever made in a component. Thanks Kevin for being patient and doing everything asked for this preamp! I just wish you were a professional modder so everyone can enjoy your expertise.
 
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So I just wanted to update you on my 18k. Recently I got a hold of the $14k Audio Research Ref 6 preamp thinking it has to beat my 18k. Well, it didn't. Quite the opposite. The modded 18k is more transparent, has more harmonic detail, more extended both high and low, has imaging/staging just as good, has better micro dynamics and is dead quiet compared to the Ref 6. I'm thrilled and surprised.
 
Wow! I'm impressed. So, I guess that means the 18K is worth more than $14K? I guess it's named 18K for a reason? Maybe it should be the Aragon $18K? :biggrin:

Also, has the full system been completed? The Carver amps and the ALS speakers getting along nicely? I hope so, and maybe you'll post some new pictures, of the latest and greatest? :rflmao::)

Oh yea, now that I think about it; I believe this preamp build thread is what inspired me to use Mundorf capacitors in a recent speaker crossover rebuild. You were so enthusiastic about the Supreme caps, so I used EVO Oils, Supremes, and Supreme Silver/Oils in my Acoustic Research AR90 rebuild. So thank you for that, as they sound great again.
Take care, and enjoy the system! :beerchug:
 
Hi good to hear from you again. I have the ALS setup, but still waiting for the amp. Bob tells me it should be completed in a month. He's been obsessing over this amp so much I'm going to call it the Carver Silver 7 Obsession. ;). I will definitely post pics when my system is complete. I'm getting the best sound I've ever had with the ALS. They are not easy to setup correctly.

I'm glad the Mundorf caps worked out for you. They are great choice for cross overs. If you want the ultimate, Duelunds are the best I've found, but they cost an arm and a leg.
 
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Dr K said:
So I just wanted to update you on my 18k. Recently I got a hold of the $14k Audio Research Ref 6 preamp thinking it has to beat my 18k. Well, it didn't. Quite the opposite. The modded 18k is more transparent, has more harmonic detail, more extended both high and low, has imaging/staging just as good, has better micro dynamics and is dead quiet compared to the Ref 6. I'm thrilled and surprised.
Click to expand...

Sweet! Reminds me that I need to get my own 18k II modded. Glad to hear such a glowing review.
 
Dr K said:
More progress from Mondialfan on my 18K project.

Here is a photo of the stock circuit board removed from chassis. The stock yellow input caps have been removed (upper left corner of photo). The stock R15 and R16 output resistors have been removed.
View attachment 777875

Here are photos of the circuit board with new Nichicon Gold KG series caps replacing the 2 large stock caps on the left side of the circuit board and Nichicon KW series caps replacing the smaller stock caps in the regulated DC circuit. The stock volume and balance pots and selector switches have been removed. The R1, R3, and R4 signal path resistors for each channel have been replaced with Naked Zfoil resistors (flat square resistors). The R15 and R16 output resistors for each channel have been replaced with Mills MRA resistors.
View attachment 777876 View attachment 777877 View attachment 777878

Finally, the circuit board placed on the bottom plate of the new chassis with the two huge Mundorf Supremne film caps on the left side of the chassis plate.
View attachment 777879

Looks pretty awesome, don't you think?
Click to expand...

-
Hello,

Can you list the specific values used for the upgraded resistors R1, R3, R4, R15, R16? & power supply caps? This would be helpful and appreciated
Kind regards
-Alex
 
mondialfan said:
Well I finally wrapped this project up. I'm really happy with how the whole thing turned out, of course Dr K was willing to go the extra yard to make sure everything in this project came out professional. The face plate and knobs Dr K had polished and then chrome and gold plated make this component look like a multi-kilobuck preamp. I've had some time to relax and listen to Dr K's new pre now and its a definite improvement over the 18k/28k pre's I have upgraded. What immediately jumps out at me is the amount of low level detail and the extended top end that appears with this pre in the signal chain as opposed to my own modded 28k. I do not hear a huge amount of added bass response, however the Acoustat Spectra 22's aren't a deep bass speaker so it might be there, but just undetectable with my configuration. I do notice an improvement in the soundstage depth which I'm sure is attributable to the better low level detail as well. When comparing his pre to mine I find myself eager to switch back to it from the 28k every time I go to compare the two. For me that is a big factor, if I am eager to switch back to one component from another one there's an improved level of musicality for me.

After performing this work I have to wonder what's the big factor affecting the sound? Most of the circuit and parts changes in this pre I've implemented in past upgrades. Dr K did go with some high end Vishay Naked foil resistors and silver wire as well as eliminating a large amount of the signal traces on the board which is definitely something I haven't done in the past. Surely all of those quality parts add up, but I have to think that the attenuators is where the biggest change was made. This experience definitely has me thinking about aftermarket attenuator options for my next personal preamp project. ;)
Click to expand...

Hey Kevin, can you explain why you replaced resistor R4 with a Z-foil when it according to the schematic it goes to ground? Am I mistaken? Also Dr K didn't mention it but it looks like you also replaced R17 with a Z-foil this looks like the feedback resistor? Am I right? Its hard to see from the pics. Finally, with all the upgrades why on earth leave in the the old metal films (R26 & R25) on the output RCAs why not a couple Mills?

Thanks for the info.
-Audiodrifter
 
You want to minimize noise in the low level stages before the gain stages amplify it. R4 to ground does produce noise. Although unrelated electronically, check out this link about resistor noise in a small preamp circuit, the first couple of paragraphs right after the opamp circuit describe the situation.

Although R25 AND R26 are in the signal path they're located after the gain stages on the output, IMO changing them from a dale RN60D low noise metal film to a z-foil doesn't gain you a lot if anything. Dr. K and I spoke about this during the planning stages and he wanted to replace resistors that may affect sound quality the most with naked Z-foils but realizing they're very expensive we tried to keep this in check.

Now if you've got an unlimited budget and can replace everything with z-foils then go for it, as long as they're all 10ohm - 100k ohm which is the range offered in z-foils.
 
Audiodrifter, After thinking about it a bit and looking over my notes and then going back to my personal pictures of Dr K's 18k I realized that we DID replace R25 & R26 with naked Z-foils, R15 & 16 were replaced with Mills. Suffice to say that you cannot see all of the work performed on this pre in the pictures. Some resistors are soldered directly in circuit at more optimal locations. In addition, some components left in the board are completely out of the circuit and no longer used, but I didn't want to pull them from the board because IMO the completely bare board would be ugly.

With that being said I stand by my last statement of replacing the resistors prior to the gain stages first as I feel that they will color the sound the most.
 
StimpyWan said:
Wow! I'm impressed. So, I guess that means the 18K is worth more than $14K? I guess it's named 18K for a reason? Maybe it should be the Aragon $18K? :biggrin:

Also, has the full system been completed? The Carver amps and the ALS speakers getting along nicely? I hope so, and maybe you'll post some new pictures, of the latest and greatest? :rflmao::)

Oh yea, now that I think about it; I believe this preamp build thread is what inspired me to use Mundorf capacitors in a recent speaker crossover rebuild. You were so enthusiastic about the Supreme caps, so I used EVO Oils, Supremes, and Supreme Silver/Oils in my Acoustic Research AR90 rebuild. So thank you for that, as they sound great again.
Take care, and enjoy the system! :beerchug:
Click to expand...

Hi Stimpy, see above for the Carver reference system.
 
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