Alpha Nirvana 39W SE Class A Amplifier GB

[xrk971]

Thanks, I updated the Etsy listing to reflect a 19v (rounded up from 18.5v) minimum. The 24v was from the prototype that used a pair of zener diodes to drop the voltage. The production switched to a voltage regulator that can withstand as much as 150vdc.

 

[gary s]

Updated my order details.

1) meanie : 1 stereo pair (Singapore) - order placed in store.
2) jacques antoine : 1 stereo pair (France) - order placed in store
3) gary s : 1 stereo pair (Australia) - order placed in store
4) mordikai : 2 stereo pair (USA) - order placed in store
5) vunce : 1 stereo pair (USA)
6) spiggs : 1 stereo pair (USA) - order placed in store
7) Francois G: 1 stereo pair (USA) - ordered in store, plus SLB PSU

 

[ro9397]

Alpha Nirvana would drive AudioKinesis Gina constant directivity satellite + Space Generator in parallel, only to 60 Hz where Gina crosses to an active distributed bass array. Gina + Space Generator: true 91.5 dB @ 7 ohm nominal, 5.7 ohm minimum, benign phase angle.

Room is 3300cf w/dispersion and very light absorptive treatment, sweet spot about 12' from Gina. 32W = 106 dB per speaker channel @ 1M. How might readers quantify or qualify SPL difference vs. 205W Maya, which never clipped nor hinted at such.

I presume 8 ohm build is ideal, but please advise. I have other speakers but Gina is the most difficult load (easiest speaker load comes next year, another satellite, true 99 dB @ 12 ohm).

Stereo = about 190W mains current, right? If I cut mains power while sleeping, what is estimated timeline to reach 90% and 100% of performance potential?

I have built dozens of amps, but only with pre-stuffed boards on precut chassis. Does anyone advise me against this build?

How do most builders get chassis cut?

What vendor do you suggest to fill BOM order? Do we have to find every single part ourselves?

Sorry for so many Qs, and kind thanks for all the effort.

 

[xrk971]

5ohm to 7ohm is not a problem. If all you need is 32w, the difference with a 200w amp is simply the headroom before clipping. 91.5dB speakers are quite sensitive but 12 ft away is 4 meters or SPL will be down 6dB. Assuming you like to hear music at max 89dB (center of dancefloor levels) and allow 6dB headroom that's 105dB. Add 6dB for being 12ft away, that's 111dB. or +20dB above 91dB. If 1w = 91dB, 2w = 94dB, 4w = 97dB, 8w = 100dB. So 101dB is about 10w. +6dB for headroom makes it exactly 40w requirement.

With a 7ohm speaker, you will get about 44w. So I think you are fine as long as you don't require your SPL levels to be higher than a typical nightclub dancefloor (need to use a loud raised voice to talk to a person next to you).

You can buy a preamade chassis with all holes drilled and tapped from the DIYA store. Either a 4U x 300mm Dissipante or a 5U x 300mm (to 400mm) can work. I am running mine at 55C heatsink temp in cooler winter weather. Probably a 4U x 400mm would be perfect. Get the UMS heatsink option as this amp was designed to be UMS compatible. I did not have to drill and tap a single hole.

We will get you the Mouser BOM shopping cart. You don't need to find the parts yoruself - one click ordering.

Hope that helps!

Vunce tells me he just got his Alpha Nirvana playing in stereo, so he will have the latest and most accurate Mouser shopping cart - please stand by.

 

[ro9397]

Wow, thanks for all the details, very helpful, and all encouraging me to buy.

Is the chassis cut for specific RCA, binding posts, and IEC jack? Does the chassis vendor also sell those parts?

What's an estimated time line for a slow builder to stuff those two boards? And no, I won't quote anyone!

 

[xrk971]

If you get the Deluxe 4U x 300mm aluminum chassis - all holes for RCA, binding posts, IEC, and XLR are precut. It’s pricey but the labor and aggravation you save is huge.

Deluxe 4U Aluminum – diyAudio Store

I think the website will have all the details on where to get the compatible hardware for the back panel.

The amp boards have about 70 components each. Assuming it takes you 2 min to stuff, solder, and trim each part that’s 140min ea. About 2.5hrs each working fairly methodically.

The SLB is about 2hrs to assemble.

The flying lead transistors harnesses are 15min ea so add 1hr for 4. SLB has two so another 30min. I see 8-9hrs to build the whole amp.

Assembling to the chassis is another 2-3 hrs.

 

[spiggs]

For a 20w build is the Antek AS3218 combined with the SLB the way to go?

 

[xrk971]

I would go 400VA. 18v normally gets 22v w/o SLB so that is marginal after 3v drop. I would go 20v.

 

[Vunce]

We should probably keep this thread dedicated for Group Buy information and keep all the build and tech stuff over on the original Alpha Nirvana thread:

Alpha Nirvana 39w 8ohm Class A Amp

@spiggs,
I’ll post a reply over there for you

 

[xrk971]

Although debugging a GB PCB - does that belong in this thread or the technical development thread? Either way is fine with me but we should be consistent.

 

[vvs07]

1) meanie : 1 stereo pair (Singapore) - order placed in store.
2) jacques antoine : 1 stereo pair (France) - order placed in store
3) gary s : 1 stereo pair (Australia) - order placed in store
4) mordikai : 2 stereo pair (USA) - order placed in store
5) vunce : 1 stereo pair (USA)
6) spiggs : 1 stereo pair (USA) - order placed in store
7) Francois G: 1 stereo pair (USA) - ordered in store, plus SLB PSU

8) vvs07: 1 stereo pair (USA) - ordered in store

 

[xrk971]

PCBs have been ordered, should be here in 7-10 days. Nice thick 2mm with 2oz copper, gold plated and blue mask.

 

[poseidonsvoice]

Is the group buy closed?

Best,
Anand.

 

[xrk971]

No, I got extras to cover late comers. I should add that this includes qnty 2 of the snubber PCBs for the remote MOSFET mounting. Believe it or not, these cost almost as much as the main PCB.

 

[meanie]

1) meanie : 1 stereo pair (Singapore)+ 1 pair SLB - order placed in store.
2) jacques antoine : 1 stereo pair (France) - order placed in store
3) gary s : 1 stereo pair (Australia) - order placed in store
4) mordikai : 2 stereo pair (USA) - order placed in store
5) vunce : 1 stereo pair (USA)
6) spiggs : 1 stereo pair (USA) - order placed in store
7) Francois G: 1 stereo pair (USA) - ordered in store, plus SLB PSU
8) vvs07: 1 stereo pair (USA) - ordered in store

 

[pistollero]

No, I got extras to cover late comers. I should add that this includes qnty 2 of the snubber PCBs for the remote MOSFET mounting. Believe it or not, these cost almost as much as the main PCB.

Hello i would like to enter the groupbuy for a stereo amp. Can you add me?

Thks

 

[meanie]

1) meanie : 1 stereo pair (Singapore)+ 1 pair SSR - order placed in store.
2) jacques antoine : 1 stereo pair (France) - order placed in store
3) gary s : 1 stereo pair (Australia) - order placed in store
4) mordikai : 2 stereo pair (USA) - order placed in store
5) vunce : 1 stereo pair (USA)
6) spiggs : 1 stereo pair (USA) - order placed in store
7) Francois G: 1 stereo pair (USA) - ordered in store, plus SLB PSU
8) vvs07: 1 stereo pair (USA) - ordered in store

 

[pistollero]

No, I got extras to cover late comers. I should add that this includes qnty 2 of the snubber PCBs for the remote MOSFET mounting. Believe it or not, these cost almost as much as the main PCB.

Hello made the order on the store.

best regards

 

[xrk971]

Thank you, Pistollero!

1) meanie : 1 stereo pair (Singapore)+ 1 pair SSR - order placed in store.
2) jacques antoine : 1 stereo pair (France) - order placed in store
3) gary s : 1 stereo pair (Australia) - order placed in store
4) mordikai : 2 stereo pair (USA) - order placed in store
5) vunce : 1 stereo pair (USA)
6) spiggs : 1 stereo pair (USA) - order placed in store
7) Francois G: 1 stereo pair (USA) - ordered in store, plus SLB PSU
8) vvs07: 1 stereo pair (USA) - ordered in store
9) pistollero: 1 stereo pair (Portugal) - ordered in store

 

[SunShade]

I don't see the SLB PSU PCB on the Etsy store, is it available, how to order?