Thanks Bfpca
I was prepared to replace all mosfets and transistors...
it looks like there was some short be twin transistors solder pads..I just sqrub it, with sharp..something...
To you who design PCBs for diyers ;
Please when you design PCB take care that those pads have some more space in be twin !!!
I have play with gain, as I don't have idea how much gain is enough,
and as I will have only AYA DAC in front of P1.7 with 2V at output, I set 3.7V be twin ''0'' and ''+'' and be twin ''0'' and ''-'' of BAL output.
(don't understand is my gain 1.85 or 3.7)
This 3.7V is setup at fully open RelVol3 (1Kohm)
Don't know if that's too much or not, at those settings trimmer have value of around 270ohm...
I was prepared to replace all mosfets and transistors...
it looks like there was some short be twin transistors solder pads..I just sqrub it, with sharp..something...
To you who design PCBs for diyers ;Please when you design PCB take care that those pads have some more space in be twin !!!
I have play with gain, as I don't have idea how much gain is enough,
and as I will have only AYA DAC in front of P1.7 with 2V at output, I set 3.7V be twin ''0'' and ''+'' and be twin ''0'' and ''-'' of BAL output.
(don't understand is my gain 1.85 or 3.7)
This 3.7V is setup at fully open RelVol3 (1Kohm)
Don't know if that's too much or not, at those settings trimmer have value of around 270ohm...
Last edited:
Thanks Bfpca
I was prepared to replace all mosfets and transistors...
it looks like there was some short be twin transistors solder pads..I just sqrub it, with sharp..something...
Please when you design PCB take care that those pads have some more space in be twin !!!
I have play with gain, as I don't have idea how much gain is enough,
and as I will have only AYA DAC in front of P1.7 with 2V at output, I set 3.7V be twin ''0'' and ''+'' and be twin ''0'' and ''-'' of BAL output.
(don't understand is my gain 1.85 or 3.7)
This 3.7V is setup at fully open RelVol3 (1Kohm)
Don't know if that's too much or not, at those settings trimmer have value of around 270ohm...
Good to hear you got it sorted out quickly!
Your gain would be 3.7/2 for a single ended output and 7.4/2 for a balanced output. That may work fine for you depending on how much voltage drive you need for your power amp. You should be able to increase that output to at least 8volts on + and - if needed, before running into any problems with clipping. I think my boards would do about 10volts before clipping.
Try it with the 3.7volt output and see how it works, then adjust from that point if needed.
I am working on the attenuators and input selector for my P. I have not had much time to work on it lately
Regards
Brian
Transformer to choose?
Hello
I have been fortunate to take over PCB:s (Kojas) for this eminent Preamp and want to start building as soon as possible....(some other projects to finish first).
Was looking into the Aleph P1.7 Service Manual and found that the choise of transformer according to drawings is Avel Lindberg D4007 wich is only a 30 VA 2x30V transformer. Most people here are using 120-160 VA transformers so what am I reading wrong!?
I was thinking of adding one transformer per channel so if I go for 40-80 VA then I am well supplied, am I not??
By the way, found this one on Conrad, would this to the job? Anyone who know anything about the transformer in HiFi equipment??
http://www.conrad.com/ce/en/product/518646/Sedlbauer-858744-50-VA-toroidal-transformer-230V-to-2-x-30-V?ref=list
Hello
I have been fortunate to take over PCB:s (Kojas) for this eminent Preamp and want to start building as soon as possible....(some other projects to finish first).
Was looking into the Aleph P1.7 Service Manual and found that the choise of transformer according to drawings is Avel Lindberg D4007 wich is only a 30 VA 2x30V transformer. Most people here are using 120-160 VA transformers so what am I reading wrong!?
I was thinking of adding one transformer per channel so if I go for 40-80 VA then I am well supplied, am I not??
By the way, found this one on Conrad, would this to the job? Anyone who know anything about the transformer in HiFi equipment??
http://www.conrad.com/ce/en/product/518646/Sedlbauer-858744-50-VA-toroidal-transformer-230V-to-2-x-30-V?ref=list
Last edited:
Check out: Power transformers - Internet shop Toroidy.pl
Great transformers at resonable prices.
//Johan
Great transformers at resonable prices.
//Johan
Its alive
Tested my Aleph P boards yesterday.
Nice no hum no Problems.
A Little bit quiet but they are configured for lowest gain at the Moment.
Started building in January http://www.diyaudio.com/forums/pass-labs/217061-aleph-60-building-thread-16.html#post4592384
next step relaxed building the psu
Tested my Aleph P boards yesterday.
Nice no hum no Problems.
A Little bit quiet but they are configured for lowest gain at the Moment.
Started building in January http://www.diyaudio.com/forums/pass-labs/217061-aleph-60-building-thread-16.html#post4592384
next step relaxed building the psu
Attachments
Volume and selector
Hi all, what to use for volume control and selector??
Have been looking at different options and thought that Dantimax was looking good but I don't know if it is still open for buisness. Last log on for the owner was more than a year ago here at DIY Audio. Don't get any answer via mail to Dantimax either.
So if Dantimax is down what then to choose??
Found Volume control at Ebay from Jims Audio directly for Aleph P1.7 that seem ok and then there is the question what selector control?
Is there maybe any better? I recieved info that I could use the Salas volume/selector so maybe there is a way to go.
I know that a lot of you builders have opinions about this so please, share your opinions with me.
Hi all, what to use for volume control and selector??
Have been looking at different options and thought that Dantimax was looking good but I don't know if it is still open for buisness. Last log on for the owner was more than a year ago here at DIY Audio. Don't get any answer via mail to Dantimax either.
So if Dantimax is down what then to choose??
Found Volume control at Ebay from Jims Audio directly for Aleph P1.7 that seem ok and then there is the question what selector control?
Is there maybe any better? I recieved info that I could use the Salas volume/selector so maybe there is a way to go.
I know that a lot of you builders have opinions about this so please, share your opinions with me.
I cannot recommend Dantimax and suggest you look elsewehere.
I bought a complete set some years ago (PSU, Control2, RelVol3, Input2, etc.) for my AP1.7. After assembly I got it working, but the sound is distorted during volume change. I have tried contacting Mikkel (Dantimax) numerous times about this but have not received a reply. The problem is bad enough that I decided to remove the Dantimax parts from my amp and am looking for a replacement.
I know other people have had good results with the Dantimax boards, so YMMV.
I do not know what is causing the distortion I have with the Dantimax boards, but think it may be due to the layout of the RelVol3 board. On the original Pass Labs boards, the relays are positioned so that the powersupply lines (feeding the relay) are kept away from the signal being switched (check the board layout in the service manual). The position of the relays on the RelVol3 board suggests that the powersupply lines are not kept away from the signal being switched. Perhaps that in my case the on/off switching current to the relays is picked up by the signal lines.
The Salas volume/selector (I-Select) is single ended. I have not yet seen one and do not know how easy it will be to use 2 for balanced.
In the original AP1.7 the attenuator (1K) is placed at the output (i.e. after the AP1.7 amplifier). The AP Manual:
The input of the gain stage is directly coupled to the input selected, without an intervening volume or balance control as seen in other preamplifiers. This provides the highest performance from the Mosfet gain devices.
The description at Jim's Audio suggests the attenuator can only be placed before the amplifier:
Input Impedance : Between 1M to 10K, the frequently used volume levels between 20K to 50K
Output Impedance : 4K to 1M, the frequently used volume levels between 4K to 30K
Output Impedance : 4K to 1M, the frequently used volume levels between 4K to 30K
Impedance of Jim's attenuator is too high for use at output, unless unit is different from the one I saw.
Apparantly you can choose both the input and the output impedance, at least in the Ebay annonce that is out for the moment, or am I wrong??
Resistor Volume Control 128 Steps Stereo P1 7 Balanced w Highly Reliable Relay | eBay
Seem little strange that they answer yes if it is no, then they are making themselfs major A...holes to future customers cause such thing will be noted in many places.