Eros 2 upgrades

[blue360cuda]

Hey everyone!  I've been enjoying the heck out of my Eros2 for 6 months or so.  The bug has bitten to tinker around and I was wondering about upgrades and what others have tried.

I'm planning on the 1.5uF 630v caps going to R/L output jacks.  Does it make any sense to change out any of the shunt regulator poly or electrolytic caps,  c4s board caps or the little 0.01uF 630v poly caps?

Other than capacitors and tubes are there any other upgrades worth looking into? Tube sockets?

The most "down the rabbit hole" post I could find was this: https://forum.bottlehead.com/index.php?topic=9491.msg88822#msg88822

I tip my hat to that gentleman! A little deeper than I intend to go, at this moment at least. Looking for the cliche best "bang for the buck" upgrades at the moment then see where it goes.

From a cosmetic standpoint, seeing about having my buddy with a machine shop cut a new chassis plate out of 0.100 copper and let it get some nice patina. And a new wood base too, why not!

 

[hmbscott]

I'm upgrading my phono cartridge from a 2M Bronze to a Hana MH, and decided to do some upgrades to the Eros 2 so that it would be "ready" for the better cartridge. ;-) Prior to the upgrades below I had only upgraded the coupling cap from the Eros's stock Solen to an Audyn Cap Plus 1.5uf. I hadn't noticed much difference from that change.

And so, I recently upgraded the coupling caps to 1uf Audyn True Copper foil and film (happens to be on clearance at Parts Express BTW), the 0.1uF film caps on the shunt regulator board from Dayton to Solen 0.10uF Silver Sound MKP, the 75K resistor to Vishay z-foil, the stock 6922 tube to a NOS Mullard 7308, and the stock EF82s to used-tested as new-Telefunken EF 86 red tips. This set of upgrades went very well and made a huge improvement. That success encouraged me to plan a few more upgrades.

So, I have ordered parts to upgrade the remaining audio path resistors to Vishay z-foils. This includes 90R9, 47.5K, 10.7K, and 47K resistors. The 47.5K I will be replacing with a 47K. The 47K 2W will be replaced with a 20K, 15K and 12K wired in series to get the needed power rating. I couldn't get a 10.7K in a single resistor, so it's being replaced with a 33K wired parallel with a 15K and 820R wired in series to yield a value of 10.69K. The z-foils are from Parts Connexion who indicates are +/-1% precision, but every z-foil I have measured is better than +/-0.1%.

Also on order are replacements for the RIAA caps. I chose the Dayton Audio DFFC 0.01uF, which while very cheap, is film and foil and should sound better than metallized film. They need to be closely matched in the RIAA circuit and the low price allowed me to order 32 of them so I can sort to get 8 closely matched.

 

[blue360cuda]

Thanks for the info Scott, sounds like you have a killer vinyl set up!  I've yet to go down the MC or MI cartridge path yet - honestly I've been hooked on the Nagaoka MM carts since I first put an entry level MP110 on my old Rega P1.  Now have a MP200 on my hot-rodded TD160 and it's just sweet. Unbelievable bang for the buck for an under $500 cartridge and bonus not having to mess with SUT.

Ok, so you obviously know way more about this electronical audio business than I do but I'm here to learn so hope you don't mind a few more questions:
-Thanks for the tip on Audyn caps,  have a pair of the 1.0uF and 0.1uF in my card now. 

Do you have any experience with the Vcaps and how they compare to these Audyn ones?  I was debating about buy once cry once if the V's are indeed as good as people say (including Paul from here).

I read in an old post (https://forum.bottlehead.com/index.php?topic=2017.0) that the original circuitry design was for 0.47mF caps instead of 1.0uF or the supplied 1.5uF in the kit. Based on the date of this post I'm assuming this is talking about the original Eros not the 2.  Does the same apply to the Eros2?  Meaning - in my Eros2 can I go with 0.47uF caps for the output instead of 1.0uF?

Another cap question - I'm reading about bypass caps in amp circuits and wondering if it makes sense to add a bypass cap anywhere in the Eros2? Also going to order some upgrade parts for my SEX2.0 so the same question applies to that guy. Would the 0.1uF Audyn caps be a good choice or is that overkill for a bypass? 

For resistors - which type is "best" for audio?  I see the Z foils you mention are metal films.  Can you hear a real world difference between these and carbon , wire wound ?

Appreciate the help!!

 

[hmbscott]

No Vcap experience. I'm something a a cap noob actually. So I have been reluctant to spend $$$ on them, which is why I have been sticking with mid range Audyn. Normally I would have been reluctant to spring for an Audyn True Copper because $$$. I have been reading cap reviews assiduously, but as I am sure you have found, it's a lot, and it's clearly a pretty subjective thing. I am convinced my most recent mods made a very big improvement, but honestly I cannot say if it's the resistor, the caps or the tubes. I suppose I should put the stock tubes back in for a comparison before I do my next set of modes to see if I can tell if those True Coppers actually can be heard or if it's probably the tubes. Although I did read somewhere in this forum that the True Copper will need 300hr of music to break in, which is a lot of albums before that test would be valid.

I think you are right that the original Eros is the one that would be OK with a .47uf cap. I couldn't find absolute confirmation that 1.0 is OK for the E2, but it seems to sound great and hints were that it should be fine. I went with the 1.0 because 1.5 was out of stock and a 2.2 was twice the price and huge. I think it would be fine to oversize it, just not especially beneficial.

Between you and me I suspect bypass caps are BS, not that it's stopped me from putting them in my Moreplay. ;-) I don't know what I don't know so I'm keeping an open mind. As far as where, I suppose in theory any large value electrolytic would be a candidate. I put some on my moreplay's power supply caps. The other place is across big expensive metallized film caps like a coupling cap, where you'd select as high a quality small value (0.01uF ?) film and foil as you can find to bypass a cheaper main cap. Just be sure the value of you bipass cap is small enough that it doesn't mess with the function of the main cap. As far as a 0.1uF Audyn goes, I'm assuming you are looking at the coupling cap, the value is fine. Presumably you would be using the top of their line, like a true copper. That would make sense. No clue if it would actually make an audible improvement.

Can I hear the difference between resistors? Not that I have been able to tell, but I haven't ever tried a clean test where the resistors are the only difference. The z-foils I have been selecting based on their specifications and the fact that Vishay markets them for high end audio. They kind of look cool too, and I am a sucker for cool looking. Spec wise I am not aware of anything better, but please keep in mind that my knowledge is extremely limited compared to folks like Paul, Paul, and Doc, and I imagine many of the other longtime forum members. I'm an engineer by training so it's not hard for me to sound like I know what I'm talking about when in fact I am blissfully unaware that I'm clueless ;-).

To anyone reading this, Please if I have said anything stupid that could mislead someone else, set me straight.

 

[Paul Joppa]

For the Eros, an output cap of 0.47uF is excellent if it's driving a 100K preamp input, probably OK for 50K ohms, and somewhat limited in the bass at 25K. It's linear,  so 1uF will drive 50K excellently, and 2uF will drive 25K.

That said, I'm driving 10K with a 1.5uF cap in my system and it's quite satisfactory to me. YMMV.

I think bypass caps became a thing several decades ago, when electrolytic caps often became inductive above about 10kHz. These days, most electrolytics are good to at least 100kHz, so the bypass affects the signal much less. (There may still be some effect on radio frequency interference.) But be aware that paralleled capacitors can interact with the parasitic inductance of the larger cap and wiring. Since parasitic inductances and resistances are sensitive to layout and lead dress, and are not always mentioned on data sheets, they seem of questionable worth to me.

Modern polypropylene caps remain capacitive to quite high frequencies, so bypassing them is pretty pointless (IMHO).

 

[hmbscott]

Paul,

I appreciate the detail on the Eros II coupling cap values. It looks like I am good with 1uf feeding my Moreplay, which has 68.7K input impedance w/ bal pot centered.

 

[hmbscott]

I'm upgrading my phono cartridge from a 2M Bronze to a Hana MH, and decided to do some upgrades to the Eros 2 so that it would be "ready" for the better cartridge. ;-) Prior to the upgrades below I had only upgraded the coupling cap from the Eros's stock Solen to an Audyn Cap Plus 1.5uf. I hadn't noticed much difference from that change.

And so, I recently upgraded the coupling caps to 1uf Audyn True Copper foil and film (happens to be on clearance at Parts Express BTW), the 0.1uF film caps on the shunt regulator board from Dayton to Solen 0.10uF Silver Sound MKP, the 75K resistor to Vishay z-foil, the stock 6922 tube to a NOS Mullard 7308, and the stock EF82s to used-tested as new-Telefunken EF 86 red tips. This set of upgrades went very well and made a huge improvement. That success encouraged me to plan a few more upgrades.

So, I have ordered parts to upgrade the remaining audio path resistors to Vishay z-foils. This includes 90R9, 47.5K, 10.7K, and 47K resistors. The 47.5K I will be replacing with a 47K. The 47K 2W will be replaced with a 20K, 15K and 12K wired in series to get the needed power rating. I couldn't get a 10.7K in a single resistor, so it's being replaced with a 33K wired parallel with a 15K and 820R wired in series to yield a value of 10.69K. The z-foils are from Parts Connexion who indicates are +/-1% precision, but every z-foil I have measured is better than +/-0.1%.

Also on order are replacements for the RIAA caps. I chose the Dayton Audio DFFC 0.01uF, which while very cheap, is film and foil and should sound better than metallized film. They need to be closely matched in the RIAA circuit and the low price allowed me to order 32 of them so I can sort to get 8 closely matched.

I've completed the upgrades listed above - felt like open-heart surgery on the RIAA circuit ;-). The tubes have had a chance to break in and the earlier cap upgrades as well. I have maybe 20 hours on the Eros with the full upgrade package. It sounded really fantastic with the Ortofon 2M Bronze, which I think pairs very well with the Eros. Shortly after I completed the Eros upgrade I installed the Hana MH cart ... and was immediately underwhelmed. I'm thinking I might have blown $$$ for nothing. But I am forever forgetting to let new components break in, especially stuff like tubes and cartridges that really need it. The Hana now also has close to 20 hours on it, which is probably still early for any real conclusions.

The Hana MH is a high-output MC cart, 2mV into 47kOhm. 2mV is on the low end of what's recommended for the Eros, and I was worried about a high noise floor because it would obviously need more preamp gain compared to the 2M Bronze (5mV). What is very surprising is that with the Hana installed noise is significantly lower than my previous noise tests, which had been done with the 2M Bronze in place and before I had done the RIAA circuit upgrades to the Eros. The way I am testing is I have the needle lifted off the record, but the TT spinning, The Eros as the selected input on the Moreplay, and I just crank the volume on the Moreplay until I start hearing noise from the speakers. Not sure why, but at this point after all upgrades and with the Hana installed, noise is way down, more than 20dB lower than it had been.

The good news is that the Hana is sounding better and better. One review suggested it may need 100 hours to realize its full potential.

I'm relieved to report that I have managed to avoid screwing up the Eros with my RIAA circuit "upgrades". Actually it's sounding awesome.

Next - waiting for the Moreplay Upgrade Kit to be back in stock, and ordered some Telefunken ECC81's (12AT7) for my Stereomour.