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.
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