Project follow up: ALEPH30

Hi all,

I'm starting this thread because I'm starting my aleph30 project. I chose it against zV4 because of the balanced input. Instead of making all my questions separately and feeding you up with my name everywhere, I'm going to describe all the process and my enquiries for suggestions within this thread. This way, anyone can follow in the future a complete project stepbystep.

I've searched for aleph30 info in other threads, but forgive me If I ask something already asked. Don't pretend to be the last resume, so you can adress the implied thread.

Well, let's start with your permission.

My system: Pro-ject RPM4 and Pioner525 as sources. DENON1801 as divorced amp, and Advance Acoustic MA11 (4Ohm and 90dB) as speakers. Very modest, but ready for upgrade system. Foreseen BOSOZ as pre.
My music: Classical with dedicated seat and sweet spot.

I have four heatsinks, sized 250x180x2.5mm, 30 fins black colour. Thought this is good enough, so I will build monoblock.

The housing is more or less taken from an old equipment, sized 125x180x240mm and is plenty of holes in the top and the bottom.

These are my questions, friends:

- As you see, there is not too much room, would be better to build the power supply separately? I've seen in the pass galery some amps built kind of crowdy, is there any problem with it?
- I will use two supplies, don't know if any sonical advantage, but this way I reduce the inrush current, because I will turn on them not at the same time. 2 toroids 300VA each and the caps specified in the original article.
- The aleph30 has 3+3 / channel mosfets that have to be heatsinked, so I'll put 3 in one side and the other 3 in the other side (I assumed they are loaded with the same current, I think 3 are for the current source and 3 for the gain). That means that more than one PCB is needed, that means that 3 mosfets will be connected to the PCB by wires, is this a problem?
- I'm checking the Aleph4 Finnis PCB (Thanks Mark, I like very much your amps), and have a question: Does R20 have to be connected to only one mosfet? Aren't the 3 blocks to be connected dead parallel? If so, R20 should "touch" the 3 of them, shouldn't they??

Thanks for your support, your help and your inspiration is greatly appreciated for this newbie.
 
Monoblock

Hi,

Thank you for your response. I knew this threads, and are very helpful. However, my project shows some differences: It's going to be monoblock due to the heat requirements vs size of existing sinks, so the pcb is not completely useful, but as a guide.

I need your help, because my question about R20 continues without any reply,, sniff,,
 

UrSv

Member
2002-01-31 5:48 pm
Sweden
The connection for R20 is clearly marked in FIGURE 1 in the conceptual diagram. It should only be connected to one of the transistors. The same goes for R15. These are the "sense" resistors and they measure only one of the source resistors respectively. When the transistors are matched the drop will be equal across each of R34-36 or R37-39 respectively.

/UrSv
 
Diodes, too big?

Thanks for your reply,

you are right, I forgot to check the preliminary drawing, I just went to the meat.
I've just got some scrap electronic equipment, and I can use some power diodes in perfect condition. They are of the threaded head type, and can be easily attached to any heat sink. I have to check a bridge with them. At first there shouldn't be any problem, right? I suppose this will withstand very well the inrush current and the charging current of the diodes.
I'm thinking about using some coil in the power supply, and as I have the cooper wire cheap-available (I work for a motors company) , I can build my own coils. I think that with 1mm2 wire will do, won't it? Does anyone has detected any improvement with a coil in an Aleph? I read that Pass highlighted the power factor improvement, but sonic improvement??
I do not intend to build my amp just from the trash bin, but I prefer to use some "bigger" things than buying standard...
My heatsinks have some scracht on the surface, but I asked for a price for anodizing and it will be cheap to recover the pristine condition again.
Does anyone knows the TROBO caps? Yesterday I visited my regular electronics supplier and there were some small caps that rated also 10.000microF 25V were 9 times cheaper. Any equivalent to Trobo?? Sikorel from Phillps are available from RS, but they are expensive. Any suggestion...??
 
My opinion, as usual, is that you start by building the amp as simple as possible. Make it work. Feel it out (don't tuch the caps though) and build yourself an oppinion on how you like it "un modded". THEN you start fiddeling around with "enhancements".

If you consider that the amp itself was pretty expensive when bought commercially, only having the "simple" scheme as stated in the manuals, it should possibly suit you without any enhancements.

After a couple of days when you have it up and running, you can start adding whistles and pipes to it. That is the joy in DIY.

Don't ruin your project by adding stuff that will only make it harder to finalize. Then you'll end up with another unfinished project in a box in your garage.

THOUGH! If you are really experienced and really knows exactly what the coils and enhancements will do to your amp. Go ahead! A challenge is always good.

Good luck!
 
Yep, you are right.

Hi swede,

You really got a point on this. I will try to make my car, and after that some "tunning". If i put too many things in my bag, I won't be able to bring it!

What I'm going to do is to make provisions for extra room.

But what about the trobos? Can I use some cheap caps for food or should I start with them?

Thanks
 
Hi,

About the Trobos: If you have them laying around, you could use them just to get started. Though you should be cautious, since they are too low on voltage ratings. The Aleph 30 is using +/- 18 V trafo (or 20 V) giving about +/- 25 volts on the caps. You should always add at least 10% for headroom on the caps. Othervise, there is a slight possibility that you get your amp-box full of really smelly cap-intestants.

If you are on a tight budget, try and make a list of everything you need for a project. Buy the parts over the time. Try and make as few compromises as possible, but if you get something for free (like caps, transformer, box or whatever), then use it!

You can start with some cheap caps and if you feel that you can make the amp SOOOOO much better, exchange them later. One of the things in DIY is to get things WORKING. Not only talking about projects that never come true!

Keep up the spirit!
//magnus
 
Simpler turn on-off delay

Hi,

Yeah, the more I think about it the more you seem to be right: I'm just going to make it work and later study the improvements.

Any suggestion about the power switch? I can't find any 25A bipolar in my shop. Will I need to buy some DIN Siemens like the ones in my house-terminal box from the electrical switch?

I'm thinking also to make it simple as I can, even the delay turn on/off will be a simple switch to do it manually. Will be better to fit a relay, or a standard switch? At the end of the day, I don't care about not having a remote control, I don't need it. That is because the way I listen to music: Ummmm, Mahler? no, I'd prefere some older music...Corelli? ummm, yes! this Concerti Grossi nº2 is perfect! Let's get the record, let's dim the lights, let's sit, let's turn off the ********** mobile and let's dream.

I don't care about the small lights and LCDs and so on, btw i use vynil, that is not the easy way...
 
hahahahahahahahaha

You tough boy....

This is a very good solution indeed, but as someone said: things should be simpler, but... AT LEAST YOU PUT A SWITCH!!!!!!!

I'll think about it anyway...

Does anyone have an opinion about the switch for the speaker cable instead of a delay relay?

I'm also thinking about an A/B output for speaker comparition: Just an manual switch of course... Call me rude, but effective.

I don't know if order the AL plates mechanised or do it by myself, is this easy enough?

:scratch2:
 
;=)

Well, I usually try to get switches as often as possible, but for my current Aleph30 (which is not yet in it's chassis) I have not yet assembled the switch.

I'm not sure if you need the switch/relay for your speakers, unless you want to build a DC protection circuit. There is an almost inaudible "hump" when I turn my Aleph on, which is not harmful for the speakers. Maybe you should not fiddle around too much with the low level inputs when power is on, but other than that the Aleph 30 is very forgiving.

//magnus
 
Switches

Switches makes a difference! I have dispensed with switches and used a small circuit breaker of about 3 amps or so which doubles as a switch and fuse as well. Soldering incoming power cables directly to the transformer also makes a difference but the final effect to you will very much depend on the resolution of your system.

If you're game, try shielding your power cord with a copper mesh braid and you'll not regret the effort!!

ckt
 

JDeV

Member
2002-10-19 7:51 pm
Home
Re: Panos PCB's

This question is actually for Panos himself, but somebody else might have the answer or want the same answer.
On the Panos Aleph30 PCB, C7 are indicated to be mounted over Q5 (Q6) from base to emitter while on the Pass circuit it is from base to collector, although there is a hole for the latter on the PCB. Which way are the correct way and can the other 1 be of any good value?
I also noticed a marking between 2 pads "C" - near R33, are this for the cap (C6) as used in Aleph5, and what would be the advantage for it on Aleph30?

Thanx for all advice and information.
 

JDeV

Member
2002-10-19 7:51 pm
Home
Re: Re: Panos PCB's

JDeV said:
This question is actually for Panos himself, but somebody else might have the answer or want the same answer.
On the Panos Aleph30 PCB, C7 are indicated to be mounted over Q5 (Q6) from base to emitter while on the Pass circuit it is from base to collector, although there is a hole for the latter on the PCB. Which way are the correct way and can the other 1 be of any good value?
I also noticed a marking between 2 pads "C" - near R33, are this for the cap (C6) as used in Aleph5, and what would be the advantage for it on Aleph30?

Thanx for all advice and information.

Found my answers here: http://www.diyaudio.com/forums/showthread.php?threadid=2206

Should have searched better, this happens when 1 wants answers 02:30am :eek:

Wont happen again.