From Bastanis Prometheus to Atlas

[selfaddict]

I finally went to the self storage place last Sunday and picked up my router. The plan was to upgrade my trusty Bastanis Prometheus to Atlas by adding a second pair of wideband drivers into them.

As always it was the preparation work which took the most of the time. But it was worth it, I did not want to make mistakes, which would stare at you all the time when, I would turn the kit on. I had bought the wideband drivers couple of weeks before this and did really not know what to expect from the upgrade.

I had felt that Prometheus were a bit over bright with Gemini tweeters and I was hoping that second pair of widebands would mellow thing out slightly. The problem is that I have done quite a lot of changes in my system, including new preamplifier and new phono stage, so it is difficult/impossible to remember how the system sounded like and make comparison.

But newer mind, I could not wait anymore, so started by sandwiching the baffles between two sheets of 18mm MDF. I had to do this because the Gemini tweeter horn was glued into the baffle and I had to get flat surface for the router. After this it was really easy to make the openings with the router and make rebate with 45 degree angled bit. I post few pictures if anyone else is planning similar operation in the future. Well worth the upgrade and easy enough to do :)

[selfaddict]

Before and after...

[Alex_UK]

Top work! You'd never know, to look at... but what about the sound?

[selfaddict]

Top work! You'd never know, to look at... but what about the sound?

Hi Alex.

The sound :scratch:

It was very interesting when I turned the kit on and heard the first notes. The sound was dark and deep, the harshness was gone for good, I felt so relieved. After listening a bit more and comparing the sound with and without the new preamplifier, I realized that the sound was too 'valvey'. So then I tried the Tesla ECC802S valves again inside the Eastern Electric. Before the second pair of widebands were installed, the sound was way too bright with Teslas, but now it was just right. I have the stock ECC83 still in situ, but I will hopefully get a pair of Mullard CV4004 soon enough to try. I want to try the Mullard CV4004 with Nicks phono stage ad well.

It all is slowly coming together finally, it is just a small task of trying to find best valve combinations between the three valve amplifiers. I need to get the sound a bit less valvey and more precice and stretch the soundstage wider and deeper. I need to try the Tesla E83CC which I have on the phono stage, when I start to think about it now :scratch:

[Alex_UK]

Good luck finding the ideal combination - looks like you're on the right path. :)

[John]

Nic e work those drivers will only get better as they bed in

[selfaddict]

Just a question of wiring the Gemini tweeters. Have I done it right when I connected the Gemini's + terminal to the + terminal on the wideband driver and same with the - ? The wideband drivers have been wired as the diagram shows in the Bastanis web page, that is from - speaker tab to first wideband - terminal, to first wideband + terminal, to second wideband - terminal, to second wideband + terminal, to + speaker tab.

http://www.bastanis.com/pdf/Mandala_cutting_plan.pdf (page 7)

Or do I need to get the Gemini tweeter wired from the speaker tabs? Sounds working OK tome, but best to be sure than sorry :)

Thanks

[John]

So is the Bass driver open back looks like it in the picture if so have you noticed what is the bass response. For me this is where the Augee really win out over the Bastanis bass speakers true Dipole creates very clean musical bass, but be interesting if they actually work as true dipole bass

[Clive]

Just a question of wiring the Gemini tweeters. Have I done it right when I connected the Gemini's + terminal to the + terminal on the wideband driver and same with the - ? The wideband drivers have been wired as the diagram shows in the Bastanis web page, that is from - speaker tab to first wideband - terminal, to first wideband + terminal, to second wideband - terminal, to second wideband + terminal, to + speaker tab.

http://www.bastanis.com/pdf/Mandala_cutting_plan.pdf (page 7)

Or do I need to get the Gemini tweeter wired from the speaker tabs? Sounds working OK tome, but best to be sure than sorry :)

Thanks
As long as the tweeter + has a direct route (ie not via a voice coil!) to the + binding post it doesn't matter how you get there. Same for - to the - binding post.

The Proms in comparison to Altas sound rather clinical. Really glad they are working well!

John, the bass in the pic will be a sealed cab with a 15" driver, this has more punch than the 18" you heard but less texture, this is the Bastanis bass tradeoff. I must add as well that you've not heard fully run in Chrystal drivers.....mine are still improving from early Dec, the difference is rather great, indeed massive.

[John]

Clive at some point it be good to hear the difference between the two

[Clive]

Clive at some point it be good to hear the difference between the two
Assuming John you mean the Chrystals, for the first 200 hours for so they sound very "nice", certainly in isolation no one would complain about their sound. With more like 300 hours now I have loads more detail, extension, bass richness, presence and some better bass dynamics (has to be due to the upper bass). I'm not commenting on Bastanis bass drivers vs Augie, more on what the other drivers are doing higher up the spectrum.

There's a huge smile on my face! And I'm guessing there's more to come yet.

How's the deck btw?

[John]

Long story Clive

[selfaddict]

As long as the tweeter + has a direct route (ie not via a voice coil!) to the + binding post it doesn't matter how you get there. Same for - to the - binding post.

The Proms in comparison to Altas sound rather clinical. Really glad they are working well!

Hello Clive and thanks for your advice, much appreciated :respect:

This is what I thought was the problem. So I need to unsolder the Gemini tweeter wires and move the + and - to the first wideband driver, where there is a direct access to the speaker binding posts. Currently the signal is going through the first wideband driver and then to the Gemini Tweeter. I assume this is mixing the signal somehow :scratch:.

I am sorry but I am hopeless when it comes to the electrics, give me a piece of timber and I will be happy, but there is something with the electrics that just doesn't work with my simple mind :doh:

I totally agree, the Gemini tweeter is overpowering with only one Bastanis wideband driver, but with two drivers in situ, something magical is appearing :).

[selfaddict]

So is the Bass driver open back looks like it in the picture if so have you noticed what is the bass response. For me this is where the Augee really win out over the Bastanis bass speakers true Dipole creates very clean musical bass, but be interesting if they actually work as true dipole bass


Hi John.

As Clive wrote, the low bass is coming from the sealed woofer cabinets. They are punchy in deed :eyebrows:. I tried once driving them without the baffles with a pair of XTZ sub amps and very high volume levels: the impact made me physically sick. Saying that the interior door opposite the woofers was banging and the windows were shaking from the pressure waves as well :mental:.

I have to say that I would be more than happy to use the baffles on their own without the sealed woofers for occasional listening.

[Clive]

This is what I thought was the problem. So I need to unsolder the Gemini tweeter wires and move the + and - to the first wideband driver, where there is a direct access to the speaker binding posts. Currently the signal is going through the first wideband driver and then to the Gemini Tweeter. I assume this is mixing the signal somehow :scratch:.



You can simply take the capacitor wire and Gemini -ve wire straight to the binding posts if you prefer.

[selfaddict]

You can simply take the capacitor wire and Gemini -ve wire straight to the binding posts if you prefer.


Hi Clive.

This is the way how it is shown it the Bastanis web page as well. Only problem is that I do not have enough the same speaker wire that Robert has used with the widebands. Would you have any in stock? It is just that I would like to use the same wire as the wideband drivers have been wired with.

[Clive]

Hi Clive.

This is the way how it is shown it the Bastanis web page as well. Only problem is that I do not have enough the same speaker wire that Robert has used with the widebands. Would you have any in stock? It is just that I would like to use the same wire as the wideband drivers have been wired with.
The wire is nice, I only have a few short pieces, nothing long enough for your ask. I drew the diagram for Rob that way for simplicity.

There's nothing wrong with taking the wires to the widebands. I have the capacitor going to the +ve on the top wideband and the -ve tweeter connection going to the -ve terminal on the lower wideband. These connections then go directly to the binding posts.