• These commercial threads are for private transactions. diyAudio.com provides these forums for the convenience of our members, but makes no warranty nor assumes any responsibility. We do not vet any members, use of this facility is at your own risk. Customers can post any issues in those threads as long as it is done in a civil manner. All diyAudio rules about conduct apply and will be enforced.

(one more) ALEPH P 1.7 clone

Status
Not open for further replies.
Jump to Latest
#541
The BG's have been on a steady diet of white noise for a couple of days so should be a bit broken in. I had a quick listen when I first finished installing and even then the improvement over the MKT1813 was quite noticeable. A couple of days down the track and things have improved even more.

It's a bit hard to tell exactly what improvement I can attribute to the N, as I've made some mod's to my DAC in the past few days, but my system is sounding much better balanced and far more detailed than it was last week. 😀 I'd definitely recommend the BG's.

The Dantimax boards are all together and had a quick bench test tonight. Everything seems to be working ok, apart from a couple of quirks which may be due to using a PLED display, but I won't have it hooked to the Aleph P until tomorrow.

I'm curious to see what impact the RelVol3 has on the sound.

cheers
Paul
 
#543
Hi,

I finished my boards and fired them up without any input or output. Voltage on the amp board is 60VDC, so that seems to be oke.

At this moment i don't have a balanced source or balanced poweramp. How can i test the complete Aleph P1.7 without these balanced devices?

I mean how to connect a normal source as a CD-player or funtion generater with sinus output and power amp or voltmeter or headphone to see the P 1.7 working (or not)?

Another question: with the powerlines connected on the P 1.7 (and having about 60VDC on it), is there any current without a source and outputdevice connected?

I hope someone can help.
 
#544
Wim,

When I was having problems with my P1.7 I discovered that there was an old post which gave the bias voltages across the input and output caps. From memory the advice was that if you had about 12-13V across the input caps and roughly double that across the output caps your pre was looking pretty healthy. When things were running correctly on my P1.7 the voltages roughly matched these values.

You can hook up RCA plugs or jacks to the inputs. bridge the - to gnd and connect signal to +, on the outputs hook + and gnd to stereo pot and then rca's jacks but do not bridge - to gnd. This will give you single ended in/outs.

Alternatively if you are using the dantimax boards select one of the phono inputs, and make up a pair of XLR to RCA interconnect cables to connect to a S/E amp.


cheers
Paul
 
#546
Hi Wim,

Yes, there is a bias current when nothing is connected. My version draws about 70mA per channel.
A good way to test the DC parameters is to measure on the amplifier side of the output caps. This should be around 28V.
Also look at the difference in voltages on both sides. These should be as close as possible and reflect the accuracy of the current sharing.
 
#547
Hi Paul,

I could not wait and tryed........

The following things hapend:

Without in- en output connected i measure about 14,5V over de inputcaps and about 29V over the outputcap. Looks good.

In and output connected as you told (cd-player on the input, very little speaker on the output) and the IRF610 on the PSU-board gets very hot in a short time, i measure between 0,2V and 0,4V on the input and about 0,1V on the output (so the speaker only gives a very little sound).

Current from PSU-board is about 70 mA.

Looks no good!

Any idee? Can it be the position of the 2K potmeter on the board? Its position is 1K at the moment.
 
#549
For a start check that you have the dip switches set correctly. Only three settings will work. I posted a image with the switch positions here:

http://www.diyaudio.com/forums/showthread.php?postid=1097060#post1097060

Are you hooking the speakers directly to the output of the P1.7? You might be able to drive headphones directly, but I doubt hooking up speakers would give much volume?

The position of the trim pot does effect gain.

My mosfets run hot too. I can manage touching with a finger for a second or two at most. This _is_ a "Class A" pre-amp after all 🙂

Paul

In case I wasn't clear in the diagram, the on/off settings refer to the switch directly above each column. The "pass labs no's" relates the switch numbers given in the Service Manual to Veteran's layout and can be ignored for purposes of configuring the board 🙂

and the pic at the bottom of this page shows precisely what I was trying to describe regarding wiring...

http://www.unisonus.com/projects/aleph_p.htm
 
#550
Thanks for all the help!

I give the dipswitches another position and trimmed the position of the 2K pot. It helps, the sound was louder.

I have to try with an poweramp on the outputs, not a loudspeaker.

What is getting warm in my situation is the IRF610 on the PSU-board, not the ones on the amp-board. But as told, i use a (mayby to) smaal heatsink on it.

Thanks again, i am going to try wit a power amp on the outputs and will report results later.
 
#551
Yes, the PSU IRF610's do get hot too

I have a small heat sink on mine and can keep a finger on the heatsink for only 3-4 seconds are a short period of running.

If I was you I'd be getting the boards hooked up to the Dantimax gear and let it sing 🙂
 
#553
I connected all parts (amp, PSU, Dantimax stuff) and fired it up.

The position of all the DIP-switches is "off", and the trimpots are set on minimum resistance near 0 Ohm). Maybye i must do some experiments, turning the trimpots a little up.

My first impresion is that it sounds great, but i did non connected it yet on my livingroom stuff. Only on low quality test stuff.

Many thank to everybody who helped me on this forum.

I also have to say the Dantimax stuff works very nice and Mikkel is allways on air to give good and helpfull advise.
 
#554
Hi guys!

Soon finished with my attempt at the preamp with dantimax boards. Do any of you know where I can get hold of DIP swithes? I don't think I need them, but it would be nice to have the option just for the fun of it!

You should post some images of your projects!

Best regards,
Folke
 
#557
dear professionals,
just begun with my aleph project 😉
can anybody tell me how much watts the "small" resistors on the psu have? also 1/4 W?
are 1/2 Watt are enough for the zeners? I bought them, couse the dealer got off the higher rated ones. i read it somwhere, but they are that small…

just my first question.
thanx
 
#558
I think 1/4W is what Veteran used for everything except the 33 and 22 ohm resistors. The board is set up for 1/2W zeners... I wound up using 1W in mine (Ebay) but had to drill the holes out (thank god for drill presses) and they are a tight fit.

Stupid question time: I assume that with 2 PSU boards, if you only want to use a single transformer that the boards can be wired off the same secondary(ies) in parallel? I had noted that most seemed to think dual 28V secondaries wired in series was the way to go, >50VA?

I was thinking of using this transformer:

Avel-Lindberg Inc

Input: 2 X 120Vac 50-60 Hz
3 3/4" Dia X 1 1/2" Tall

Output: 2 X 28.4V @ 2.67Amps over 150Va

$22.00ea

from http://www.apexjr.com/miscellaneous.html#Toroids. Would this be acceptable? On the wiring instructions they seem to indicate that this is center taped, but the specs would make it seem to be dual secondary (which I would prefer as it is more flexible).

I also think I will be using the Dantimax stuff for mine. Any recommendations for what I need? The one thing that I would also like is an aluminum remote... looks like the diyclub link has those... I am wondering whether that would work with the Dantimax stuff?

Chris
 
#559
grounding question..

Hi All

This might seem like a silly question since my preamp is working. 🙄

However i seem to have some sort of ground problem..
This problem only occurs when i,m using the preamp with one of my poweramps (a tripath based one)

So, i,m thinking that maybe my grounding is,nt good enough.

How did you guys do the grounding?, Could someone maybe draw a simplified schematic of there grounding ?

Regards

/Z
 
Status
Not open for further replies.
Top Bottom