Aleph 5 and 625VA transformer

Jye · 21st January 2005, 03:22 AM

Hi,

I am in the middle of putting together an Aleph 5 (using Mark Finnis PCB) and would like to up the bias as high as the heat sinks allow once completed (possible removing R19)

So I would like to know if a 625VA transformer would be large enough OR if I should be looking at getting an 800VA transformer?

Cheers
Jye

BURNER · 21st January 2005, 03:30 AM

625 VA should be fine

SteveA · 21st January 2005, 05:19 AM

I used a 625 VA transformer on mine and it works fine for me.
Steve

Jye · 21st January 2005, 05:38 AM

Thanks for the replies.

Did u increase the bias SteveA and if so to what?

SteveA · 21st January 2005, 05:49 AM

Jye-
No, I built it as per Pass schematic (at least main boards and output boards). For PSU I used a CLC (68000-2.2mH-68000 on each rail). I used a single rectifier as per Wayne Sankey's Aleph 2 (see Passdiy).
SteveA

DirkD · 21st January 2005, 10:15 AM

hi there Jay

I built an Aleph 5 with standard bias using a 625VA transformer and feel that it is under a bit of stress. It tends to get hotter than I am accustomed to. If I were to build another Aleph 5 I would select at least an 800VA transformer, especially if I wanted to increase bias.

Regards

Dirk

Duck-Twacy · 21st January 2005, 07:58 PM

If you can afford it go for the 800 (or twin 500). You may regret it later (and then changing is a lot more expensive)

Nelson Pass · 23rd January 2005, 01:51 AM

Quote:

Originally posted by Jye
Did u increase the bias SteveA and if so to what?

In general, you get the bias up as high as you dare. Scale the
transformer/ caps/ heat sinking accordingly.

If you can't scale the heat sinks, you'd be amazed at what a
little bit of air flow will do for you.

Jye · 23rd January 2005, 11:50 PM

Thanks for the reply guys, I will go with the 800 since I plan to up the bias as high as I dare

and if need be will use a fan.

I hope to post some finished results in 2 - 3 weeks...only a few things missing.

Jye

Berry · 28th January 2005, 08:31 AM

jye,

I use 625w transformers for an aleph 5. The amp sounds ok, but in the first 20 minutes there is a mechanical hum from the transformers, no hum to the speaker !. The bias is about 20 % higher then the original aleph.

So, take a 800W transformer.

21st January 2005, 03:22 AM	#1
Jye diyAudio Member Join Date: Aug 2003 Location: Brisbane, Australia	Aleph 5 and 625VA transformer Hi, I am in the middle of putting together an Aleph 5 (using Mark Finnis PCB) and would like to up the bias as high as the heat sinks allow once completed (possible removing R19) So I would like to know if a 625VA transformer would be large enough OR if I should be looking at getting an 800VA transformer? Cheers Jye

21st January 2005, 07:58 PM	#7
Duck-Twacy diyAudio Member Join Date: Oct 2002 Location: Holland, The Hague	If you can afford it go for the 800 (or twin 500). You may regret it later (and then changing is a lot more expensive) __________________ Is that all there is?

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21st January 2005, 03:30 AM	#2
BURNER diyAudio Member Join Date: Nov 2003 Location: Bangkok	625 VA should be fine

21st January 2005, 05:19 AM	#3
SteveA diyAudio Member Join Date: Dec 2001 Location: St Paul, MN	I used a 625 VA transformer on mine and it works fine for me. Steve

21st January 2005, 05:38 AM	#4
Jye diyAudio Member Join Date: Aug 2003 Location: Brisbane, Australia	Thanks for the replies. Did u increase the bias SteveA and if so to what?

21st January 2005, 05:49 AM	#5
SteveA diyAudio Member Join Date: Dec 2001 Location: St Paul, MN	Jye- No, I built it as per Pass schematic (at least main boards and output boards). For PSU I used a CLC (68000-2.2mH-68000 on each rail). I used a single rectifier as per Wayne Sankey's Aleph 2 (see Passdiy). SteveA

21st January 2005, 10:15 AM	#6
DirkD diyAudio Member Join Date: May 2004 Location: Paarl, South africa	hi there Jay I built an Aleph 5 with standard bias using a 625VA transformer and feel that it is under a bit of stress. It tends to get hotter than I am accustomed to. If I were to build another Aleph 5 I would select at least an 800VA transformer, especially if I wanted to increase bias. Regards Dirk

28th January 2005, 08:31 AM	#10
Berry diyAudio Member Join Date: Apr 2004 Location: Netherlands	jye, I use 625w transformers for an aleph 5. The amp sounds ok, but in the first 20 minutes there is a mechanical hum from the transformers, no hum to the speaker !. The bias is about 20 % higher then the original aleph. So, take a 800W transformer.

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