3e Audio A7 (with 48v/10 amp power supply) vs 2 Fosi Audio ZA3 amps running in mono?

[Wick76]

I recently inherited my dad's old Bose 901 Series II speakers. I am putting together a little experimental system to get them up an running. I don't want to break the bank, so I am planning on using a WiiM Ultra as the brains and EQ replacement for the original analog EQ that came with the Bose 901s, and an RSL Speedwoofer 10s MKII subwoofer. My question is, which amplifier option would you use...an 3e Audio A7 amplifier with a 48v/10 amp power supply, or 2 Fosi Audio ZA3 amps running in mono to power the 901s? It looks like the power output would be similar with both setups, but the Fosi ZA3s are on sale now, so 2 of them would be cheaper than the single 3e A7 with the upgraded power supply. Let me know your thoughts.

 

[Ruediger]

WiiM Amp Ultra
WiiM Vibelink
3e audio A5
3e audio A7

From what I've read (interesting speakers) they present an 8 ohm load, no challenge for an amp and it is upon you to decide how much power you want/need. Their problems seem to be their wave guides (not UV resistant), internal wiring and poor terminals.

 

[kemmler3D]

I'd go for the 3E for sure. Better SINAD probably doesn't matter that much in this case, but it has PFFB so it's not load-dependent like the Fosi. It's only a matter of +/- 1.5dB at 20KHz so also probably not that problematic in practice, but for peace of mind, if it is not much more money, I'd go with the 3e.

 

[Ruediger]

If mono is desirable, the 3e audio A7 mono comes with a good GaN 48v5a psu. All that is needed.

 

[Talisman]

I recently inherited my dad's old Bose 901 Series II speakers. I am putting together a little experimental system to get them up an running. I don't want to break the bank, so I am planning on using a WiiM Ultra as the brains and EQ replacement for the original analog EQ that came with the Bose 901s, and an RSL Speedwoofer 10s MKII subwoofer. My question is, which amplifier option would you use...an 3e Audio A7 amplifier with a 48v/10 amp power supply, or 2 Fosi Audio ZA3 amps running in mono to power the 901s? It looks like the power output would be similar with both setups, but the Fosi ZA3s are on sale now, so 2 of them would be cheaper than the single 3e A7 with the upgraded power supply. Let me know your thoughts.

Are you sure you can replace their equalizer? Do you know exactly what and how to equalize? To work well, that speaker absolutely needs the default equalizer.

 

[linuxfan]

Deer Creek Audio sells a miniDSP which is pre-configured with what they claim are the correct EQ settings for the Bose 901's -
https://deercreekaudio.com/products/eq901
If you prefer to manually set up DSP settings a Reddit user called inguz provided his Bose 901 miniDSP project files here -
http://cabezal.com/pix/901-minidsp-ucd/

 

[linuxfan]

It would be interesting to know if digital room correction software could correct the crazy frequency response of the Bose 901!

 

[Wick76]

I am mainly experimenting with the WiiM Ultra to see if I can accomplish the equalization without having to use the original EQ. I have searched around other forums and been given some starting points to try out. Allegedly, there have been others that have accomplished this, but no one has posted their actual EQ parameters. Hopefully I can get close and let the room correct finish the final tweaking.

I actually already own a Deer Creek Audio miniDSP. I plan on using it when I get my dad's old Pioneer SX-950 back from the repair shop. This setup is only temporary. I plan to purchase a different set of bookshelf speakers for this system and have my vintage setup in a separate listening space. I am mainly concerned with what amp/amps to use. Any suggestions would be appreciated.

 

[Wick76]

I'd go for the 3E for sure. Better SINAD probably doesn't matter that much in this case, but it has PFFB so it's not load-dependent like the Fosi. It's only a matter of +/- 1.5dB at 20KHz so also probably not that problematic in practice, but for peace of mind, if it is not much more money, I'd go with the 3e.

I have heard great things about the 3e Audio amps. I will probably just pull the trigger and purchase one. I just hate that there are not a lot of purchasing options for their products. AliExpress has always seemed a bit shady to me, and the Amazon seller is called "Generic Store". At least the Amazon listing is Prime with free returns.

 

[livinon2wheels]

I recently inherited my dad's old Bose 901 Series II speakers. I am putting together a little experimental system to get them up an running. I don't want to break the bank, so I am planning on using a WiiM Ultra as the brains and EQ replacement for the original analog EQ that came with the Bose 901s, and an RSL Speedwoofer 10s MKII subwoofer. My question is, which amplifier option would you use...an 3e Audio A7 amplifier with a 48v/10 amp power supply, or 2 Fosi Audio ZA3 amps running in mono to power the 901s? It looks like the power output would be similar with both setups, but the Fosi ZA3s are on sale now, so 2 of them would be cheaper than the single 3e A7 with the upgraded power supply. Let me know your thoughts.

I personally think the 2 Fosi amps would be a nicely tricked out system. In the right environment, Bose 901s can sound pretty good. There was a dealer here locally that had a pair set up so they reflected off a brick wall behind them. The effect was a nice wide image and a sense of spaciousness that is hard to get with normal front facing speakers. I always wanted a pair of them just because of the nostalgia, but I dont have a good place to play them properly. And at this point in my likely never will. Adding a sub to a pair of those is a brilliant idea. Their low bass response was not the best and their equalizer put very large demands on the amplifier driving them. I'm guessing, something approaching 10 db of gain for the lower frequencies which means an amplifier that was good enough mid band at 100 watts would need to put out a 1kw at low frequencies not to have bandwidth issues at high listening levels.

 

[xanalog]

Please do yourself a favor and play it safe.
If your dad (Rest in Peace) was not recently and actively using the Bose901s and 901's accompanying "Active Equalizer" unit.

Are you sure you can replace their equalizer? Do you know exactly what and how to equalize? To work well, that speaker absolutely needs the default equalizer.

In addition, the 901s being 50+ years old need some serious attention and possible some replacement parts. Suspect every foam surround (x18) as candidate for possible replacement (foam degrades and disintegrates much earlier than 50yo).
It would also be a good idea to either check all capacitors, active/passive internal components, wiring, solder-joints for both the 901s and EQ or get them expertly 'rejuvinated'.

Let us know how you are going to finally finish this good project.
It may end up costing you a lot more than just two ZA-3s (on a sale price) but hope you make your dad proud.
FWIW; I am an owner of a Soyyin (3E) A7 stereo.

 

[Wick76]

Please do yourself a favor and play it safe.
If your dad (Rest in Peace) was not recently and actively using the Bose901s and 901's accompanying "Active Equalizer" unit.

In addition, the 901s being 50+ years old need some serious attention and possible some replacement parts. Suspect every foam surround (x18) as candidate for possible replacement (foam degrades and disintegrates much earlier than 50yo).
It would also be a good idea to either check all capacitors, active/passive internal components, wiring, solder-joints for both the 901s and EQ or get them expertly 'rejuvinated'.

Let us know how you are going to finally finish this good project.
It may end up costing you a lot more than just two ZA-3s (on a sale price) but hope you make your dad proud.
FWIW; I am an owner of a Soyyin (3E) A7 stereo.

The Bose 901 Series I and II speakers have a cloth surround, so I should hopefully be good there. I will address any other issues as they come up. This is a bit of a sentimental project for me as well. My dad is in the early stages of dementia, so I am trying to get his old system back up and running so he can hear it in all its glory again. This system was a big part of my youth, and a big reason for my lifelong love of music, so I am willing to go the extra mile to get it back up and running.

 

[livinon2wheels]

The Bose 901 Series I and II speakers have a cloth surround, so I should hopefully be good there. I will address any other issues as they come up. This is a bit of a sentimental project for me as well. My dad is in the early stages of dementia, so I am trying to get his old system back up and running so he can hear it in all its glory again. This system was a big part of my youth, and a big reason for my lifelong love of music, so I am willing to go the extra mile to get it back up and running.

Those cloth surrounds may need more of the tacky viscous goop that is used to seal up the fabric's pores. Not sure where to get it or what its called, but I would try one of the speaker repair places like Simply Speakers. I have no experience dealing with them but have seen others recommend them for vintage speaker repair kits and such. Good luck with your project!