New Aleph Mini PCB GB

[Coulomb]

I am going to be buying some 400VA 15-0-15VAC R-Core transformers for my Mini A and Aelph 30. They will be $65 US plus shipping to me (to be shared equally) and then shipped to individuals. Shipping would be about $10 each to ship from Hong Kong to Toronto, Canada and $10 Each to ship from Toronto to anywhere in North America via ground.

Here is a Photo of the product. The dimensions are as follows:

An externally hosted image should be here but it was not working when we last tested it.

165mm X 135mm X 75mm
3.8KG

Approximately $85 US each all told for a high quality R-Core transfomer, not bad all in all. I need to order 15 to make the minimum qty for the custom configuration. I have orders for 8 already. Please email me ASAP if you are serious about participating.

Regards

Anthony

 

[jleaman]

I am going to be buying some 400VA 15-0-15VAC R-Core transformers for my Mini A and Aelph 30. They will be $65 US plus shipping to me (to be shared equally) and then shipped to individuals. Shipping would be about $10 each to ship from Hong Kong to Toronto, Canada and $10 Each to ship from Toronto to anywhere in North America via ground.

Here is a Photo of the product. The dimensions are as follows:

An externally hosted image should be here but it was not working when we last tested it.

165mm X 135mm X 75mm
3.8KG

Approximately $85 US eache all told for a high quality R-Core transfomer, not bad all in all. I need to order 15 to make the minimum qty for the custom configuration. I have orders for 8 already. Please email me ASAP if you are serious about participating.

Regards

Anthony

weird the photo didnt work for me.. and what is eache ?

 

[jleaman]

It';s working now..but actually here is a better pic.. Pic stolen from krell group buy..

 

[Coulomb]

It';s working now..but actually here is a better pic.. Pic stolen from krell group buy..

This transformer is of poorer quality as it has no screen and a cheaper metal stamping.

Regards

Anthony

 

[chrisb]

bias setting for 4 or 16ohms

Thanks to Jason & Dave, I'll be embarking on assembly of mini-A shortly.

My main question is that since it's almost certain the amp will driving only bipoles (either CSS WR/FR125 or Fostex FE127E)

Is there a consensus whether the 10watt version of this unit sounds better in either 4 or 16ohms. If not, my preference in the past with tube gear has generally been with series (16ohm) wiring.

In either case, can anyone advise, or point a link to instructions on the recommended bias resistor values for 4 or 16ohms.

thanks all y'all

 

[jleaman]

Chris that's 15 Watts with 20- + V rail's.

 

[chrisb]

thanks, J

Chris that's 15 Watts with 20- + V rail's.

for the correction

my original question stands to the builders group - any preference for sonic merits in 4 vs 16 ohm loads? and if so, how does a math challenged old fart determine any necessary revision to bias setting resistors?

I've tried a quick search on the subject, and results were either none, or every thread ever referencing the mini-A.

 

[jleaman]

Re: thanks, J

for the correction

my original question stands to the builders group - any preference for sonic merits in 4 vs 16 ohm loads? and if so, how does a math challenged old fart determine any necessary revision to bias setting resistors?

I've tried a quick search on the subject, and results were either none, or every thread ever referencing the mini-A.

I found this...

Keep in mind that you can jack up the bias by increasing R11. The stock value for the Mini-A is 47k. That gives you about an amp of bias. Just for fun, I tossed in a 220k resistor, and ramped up the bias to something like 1.6A.


Here ....http://www.diyaudio.com/forums/showthread.php?s=&threadid=2001&perpage=50&pagenumber=1

Post # 16

Sorry this is R13 NOT R11

Resistor 13 is the one you want to change.

 

[mpmarino]

some experience to share..

In my quest to get this thing going I found it nice that others have shared thier Aleph experience as it helped tremendously! Here are a couple of my experiences...
_________________________________________________________
Just as a reference as to what you may see or expect regarding bias bias on the mini-a. Mine works nicely and measures as follows:

I am using .5R source resistors and rails are +-~17v. My output resistors are 4x1R in parallel.

-With r13 at 47k I get .55v across the resistor (1.1a).

-With r13 lifted I get .68v across the resistor (1.36).
__________________________________________________________

I had 1 noisy channel.. tons of distortion. It was a bad protection zener. This has happened to me before on an A30! I pulled all my protection zeners because I seem to have NO luck with them.

__________________________________________________________

I had seemingly irreconcilable hum. I am using dual supplies but This may help on single supply too. The hum was there with or without inputs..inputs shorted...not shorted..whatever.Nothing seemed to work. The solution ended up to be doing a 'serial' board ground. In other words..I took a wire from the star ground into board 1, then wired the ground of board 2 directly to the board 1 ground (at board 1). Board 2's ground does NOT go to star. Hum gone

LOL. I was left with a faint buzz and spent HOURS troubleshooting to no avail. The other night I decided to let the amp 'burn in' all night in the garage by just leaving it powered. As I left the garage I turned off the florescent lights.. guess what..buzz gone. DOH!

Marc

 

[steenoe]

Please find attached Aleph 5 part designations for brian's pcb,s if somebody else wishes to check for errors please feel free to report your findings.

Just found this XLS file in post #615 Did you guys consider R8 in the original Aleph 5 schematic? The input resistor for singleended is only 1K. (R8) It is connected after the 10K resistor for Balanced input! Any thoughts on that?

Steen

 

[winslow]

The boards are beautiful, got mine today.

 

[BrianGT]

I still have a few aleph amp boards left, and I just received a new batch of power supply boards, purchased in part for Mark's KSA GB.

I have about 5 amplifier pcb sets, and about 50 power supply pcbs. I put them on my chipamp.com order page, on the bottom:
http://www.chipamp.com/orders.shtml

If anyone wants their finished Aleph amps from the Mini-A boards put into my gallery, drop me an e-mail with pictures (link on site), and I will upload them here:
http://www.briangt.com/gallery/miniAleph

As for my projects with the boards... I have boards and chassis for building 3 amps, a mini-A, a30 and a60, but I haven't had time to finish any of them. I will try to find time soon.

--
Brian

 

[BrianGT]

Pictures of fcel's amp:
http://www.briangt.com/gallery/aleph-fcel/

An externally hosted image should be here but it was not working when we last tested it.

Great looking amp!

--
Brian

 

[jmmartins]

Hi Brian

I went to your order page and it seems you are out of stock of PCB,s. Are there going to be available new ones or that,s all.
If you are thinking on new ones, i,m interested in 4 Pcb sets.
Thx

 

[BrianGT]

Hi Brian

I went to your order page and it seems you are out of stock of PCB,s. Are there going to be available new ones or that,s all.
If you are thinking on new ones, i,m interested in 4 Pcb sets.
Thx

I ran out of amplifier boards. I only have power supply boards now.

I can create a Wiki, and if there is enough interest (at least 50 boards), I can do a reorder.

--
Brian

 

[winslow]

I was interested in another couple.

 

[Illusus]

Hi Brian, I'm interested in some Aleph Mini boards. I'll be on board(ugh) for a few if you start another run.

 

[BrianGT]

I revived the Wiki:
http://www.diyaudio.com/wiki/index.php?page=miniALEPH+PCB+Group+Buy

Please indicate your interest in the PCBs. Once we get interest in 50 boards, I will submit a new order for the pcbs.

--
Brian

 

[Stabist]

As for my projects with the boards... I have boards and chassis for building 3 amps, a mini-A, a30 and a60, but I haven't had time to finish any of them. I will try to find time soon.

--
Brian

Something similar in my case ...

Almost everything gathered and waiting to build A5, A3, A30 and MiniA - but no time
(ok, what to do with so many Alephs is allready another story)

 

[Lucas_G]

Beautiful Boards!

I just ordered 2 sets of Amppcbs and 2 supplyboards on the Wiki.

Thanks!