I’m a fan of the Eros. It has a sonic signature that I’ve not been able to get with other stages. It sounds great, is reliable and has readily accessible tubes. Best of all it’s supported by the BH team and community. If you are in the market for a phono stage, I highly recommend the Eros.
My Eros project is completed and burning in as I type. This is my third in a way having a tape version and previously owning a Tube Phono before it found its way to Mexico in the hands of another BH member. I’ve wanted to try a couple of mods and was always limited by the top plate size so for this amp I cut a 12†x 12†top plate to work with. This allowed me to use a custom walnut base that has been an ornament since the BeePre found a new home.
The top plate was cut using a jig saw for the square holes and a small table top drill press for the round ones. The vent holes are a line of small round holes as I wasn’t able to get the jig saw in for a straight cut. That drill press is one of the best investments I’ve made in this hobby, never again will I hand drill unless absolutely necessary.
With a little more room to work, the standard RCA’s were replaced with the Neutrix recessed style plugs. I like the look of them and had them on hand. They give the amp a cleaner look IMO.
Circuit wise the servo circuit was removed. This does make a difference in the sound that I’ve experienced. It was easier to build it without the servo vs. remove it later. I moved the 47k 2w resistor up to the C4S board to clear some room around socket C (thanks PB) and replaced the 100uF lytic cathode cap with a 100uF Panasonic 500v film cap. I’ll post more on how this worked once I get some hours on the amp. PJ posted once that it has a potential to pick up noise and that’s what I’ll be listening for. It will be easy put the lytic back if there is a problem. The RIAA caps are Muticap RTX polystyrene film and foil. More to follow as this is my first time using them. A few resistors in the signal path were also upgraded as was suggested by PB in previous posts. The 0.1uF cap in the shunt reg circuit was upgraded to a Solen film and foil for no other reason than to try this new cap. The output cap was upgraded to a Solen Teflon film and foil 0.47uF again to try them out as compared to the V-Caps as they are considerably cheaper.
The EF86 was originally replaced with the 6BR7. I used this originally in my first Eros and enjoyed it before swapping it to EF86. In my sonic memory I didn’t notice a difference between them and the Tele EF86’s. I have quite a few on hand and am able to find quiet pairs for use. Grainger posted a thread with all of the varients that you can use for the EF86. The 6BR7 works for me, they are cheap and I’ve got them at home. My problem came into testing it without the servo circuit. After searching the archives, I found my posts from five years ago where I had the same problem. In short, my 20 examples of the tube are not able to meet the minimum voltages required with the servo removed. If you are intending the keep the servo circuit in your Eros, I highly recommend this tube. After swapping the pin outs back to the EF86 there were three pairs in my stash that met voltage requirements.
The height of the standoff’s around the RIAA were increased by ½â€. This allows more room to work and makes it easier to test. You will notice a couple of standoffs to the right of the PS transformer. These are for a choke to replace the 270 Ohm PS resistor. This is a questionable mod but once it is burned in and I spend a few months with it to get a sonic signature, I’ll make the mod and see if there is any audible improvement. If not, It’s an easy swap back. I’ve got a Hammond 159M standing by. It’s a 15H choke and pretty large.
There is two layers of Dynamat Extreme on the exposed areas of the top plate. This adds some mass and helps to deaden the top plate ring when you tap on it. Not sure if this helps but it gives me peace of mind. The stock tube shields were replaced with IERC coolers in the hope that I’ll get a few more hours out of the tubes and they look better with this build. The 12BH7 is the stock tube that BH sent with the kit and the 6922 is a Amperex Holland 6DJ8 that tests stronger in the circuit than any of my 7308’s or 6922’s. The Amperex tubes are my favorite flavor. Just a hint of sweetness and wonderful tone.
The EF86’s are Tele grey plates. One is an EF806S and the other an EF86. Don’t get too wrapped up on the 806S. I’ve had a few of them and they can get noisy too. Some on the forums say that a lot of the grey plates out there are the 806S rejects. I can see no difference in build structure and you can’t tell how quiet it is until you put it in the circuit. The other two pair of tubes that met spec were a pair of Tele silver shields and a pair of GEC CV4086’s. I hear no difference between silver and grey shield tele’s nor between grey plate Tele’s and the Tele 806S. The GEC’s do sound different and equally great with the Amperex tube.
Overall this was a challenging build and I’m thankful to have had a half dozen kits under my belt before starting it. I do share another builders’ criticism with the manual, it is in need of an update. All in all though it was fun and I’m happy to have an Eros back in my vinyl system. More to follow as it burns in and I get some hours of listening on it.
