hello, I'm making the preamp in question because I want to match it to the final stereo ready (aleph mini version of 10W single end);
looking at the circuit, I noticed the presence of a trimmer 2K, so I ask what is its setting (I guess this is for the bias current for proper operation of the differential);
two more questions:
Which property should have the electrical power transformer (the secondary output and power?)
what value of potentiometer 4 sections I use to create the volume control and where to enter (entry or output?)
thank you very much for your important help.
looking at the circuit, I noticed the presence of a trimmer 2K, so I ask what is its setting (I guess this is for the bias current for proper operation of the differential);
two more questions:
Which property should have the electrical power transformer (the secondary output and power?)
what value of potentiometer 4 sections I use to create the volume control and where to enter (entry or output?)
thank you very much for your important help.
hello.
for the transformer. you can use a 2x30V 160VA with secondarys conected in series. the 2k pot, isn't that the secondary volum pots?
160VA
Are you sure of this information?
surfing the net, I found the site KK-PCB, where I saw the power supply for aleph P1.7;
60Volt 50VA transformer is indicated for both channel,,,this indication is correct?
trimmer 2K is on the branch connecting the differential, I need to know how to make its regulation, that is, which parameter should I refer?
if I understand it, reading the manual of the great Nelson Pass, the volume control must be placed on the input of the preamplifier, using a binary system to relay, I wonder if you can use a simple potentiometer four sections, and if so what value?
thanks
Then I can use a transformer with a secondary 60V 50VA x,,,
I have an ALPS potentiometer 10K x 4 sections, I can use it by inserting it between the input and the preamp and the same fine-tune the gain using the trimmers from 2K that I have already put on board the pcb's?
thanks so much for your interest
Gianni
This thread is a bit confusing. The attenuator of the original Aleph P1.7 is on the output of the preamp, and is 1Kohms.
If you are going to attenuate the input you can use anything you wish, but 10K would be a very good choice.
Your trimmer sets the gain of the differential, the lower the setting, the more gain. I believe I read that around 200ohms is what most people like the best.
50VA is plenty.
Best, Bill
I love that avatar, Mr Natural, R. Crum. Brings back memories of my wild youth.
If you are going to attenuate the input you can use anything you wish, but 10K would be a very good choice.
Your trimmer sets the gain of the differential, the lower the setting, the more gain. I believe I read that around 200ohms is what most people like the best.
50VA is plenty.
Best, Bill
I love that avatar, Mr Natural, R. Crum. Brings back memories of my wild youth.
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I repeat this 3-D, because I finished wiring my Aleph P1.7 and I need to ask yourself some questions:
I state that the preamplifier is driving a pair of mini aleph and its input is connected to a source with balanced output
I used an attenuation Ladder 10K, inserted on the input of the preamplifier and I set it at 150 ohms, trimmer 2K;
the sound is fantastic and considering that capacitors polypropylene still fresh, imagine what they feel when they have completed the running-in phase;
But I have a small problem, that the speakers (Nagaoka BLH with FE208ES and TA-900), emit a noise (white noise) that is independent of the variation of volume attenuator,,, this noise can be heard approaching the speakers because in listening distance (about 3 meters), not you feel;
At first, I thought, this, was generated by the fact that I have made a single wire input wiring with unshielded silver and bringing all the masses to the star, but I discarded this hypothesis because there is no change in noise when dipswitch act on incoming mail, because it remains constant;
so I thought that perhaps the value of 150 ohms (trimmer) is too low, or indeed, as many of you have advised me, I have to move the volume control on the output of the preamplifier,,,
Whereas not yet adjusted the resistance of the trimmer to a higher value,,, in your opinion where is my problem?
if you say I put the volume output where can I buya potentiometer to four sections with a value of 1 to 2 K?
Best wishes to all and thanks for your answers
http://img845.imageshack.us/i/10032011325.jpg/
http://img861.imageshack.us/i/10032011325.jpg/
[IMG=http://img861.imageshack.us/img861/9766/10032011325.th.jpg][/IMG]
Gianni
I state that the preamplifier is driving a pair of mini aleph and its input is connected to a source with balanced output
I used an attenuation Ladder 10K, inserted on the input of the preamplifier and I set it at 150 ohms, trimmer 2K;
the sound is fantastic and considering that capacitors polypropylene still fresh, imagine what they feel when they have completed the running-in phase;
But I have a small problem, that the speakers (Nagaoka BLH with FE208ES and TA-900), emit a noise (white noise) that is independent of the variation of volume attenuator,,, this noise can be heard approaching the speakers because in listening distance (about 3 meters), not you feel;
At first, I thought, this, was generated by the fact that I have made a single wire input wiring with unshielded silver and bringing all the masses to the star, but I discarded this hypothesis because there is no change in noise when dipswitch act on incoming mail, because it remains constant;
so I thought that perhaps the value of 150 ohms (trimmer) is too low, or indeed, as many of you have advised me, I have to move the volume control on the output of the preamplifier,,,
Whereas not yet adjusted the resistance of the trimmer to a higher value,,, in your opinion where is my problem?
if you say I put the volume output where can I buya potentiometer to four sections with a value of 1 to 2 K?
Best wishes to all and thanks for your answers
http://img845.imageshack.us/i/10032011325.jpg/
http://img861.imageshack.us/i/10032011325.jpg/
[IMG=http://img861.imageshack.us/img861/9766/10032011325.th.jpg][/IMG]
Gianni
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One possibility, not the cheapest.....
Dantimax (elektronik) - Selectors_-_attenuators
Dantimax (elektronik) - Control_boards
Dantimax (elektronik) - Power_supply_kits
I recommend the Dale set of resistors....
Works fine in my Aleph P 1.7, Even remote control is possible.
You need all three parts to get a working unit..... Site is not very informing.
And you need a remote, Philips
...
Dantimax (elektronik) - Selectors_-_attenuators
Dantimax (elektronik) - Control_boards
Dantimax (elektronik) - Power_supply_kits
I recommend the Dale set of resistors....
Works fine in my Aleph P 1.7, Even remote control is possible.
You need all three parts to get a working unit..... Site is not very informing.
And you need a remote, Philips
...
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Language differences may be a problem here but I'll do my best.
Because you are not attenuating the output and you also have high efficiency spkrs, any noise that is present in the circuit will be amplified in the power amp and emitted from the spkrs. I'm sure you already know this.
Excess white noise is usually associated with random electron motion in components such as carbon resistors and filter caps, but it can come from other things too.
I must question your input wiring scheme and your grounding scheme. The chassis should not be your star ground point. The circuit ground should be isolated from the chassis. I suspect your excess white noise is coming from this.
If your attenuator is a true ladder type then you dont really have balanced inputs as that would require an 8 section switch. I suppose you have a 4 pole series attenuator.
An output attenuator is more easily done with a relay unit such as a Dantimax attenuator. They are not too expensive.
Generg, you beat me to it.
Because you are not attenuating the output and you also have high efficiency spkrs, any noise that is present in the circuit will be amplified in the power amp and emitted from the spkrs. I'm sure you already know this.
Excess white noise is usually associated with random electron motion in components such as carbon resistors and filter caps, but it can come from other things too.
I must question your input wiring scheme and your grounding scheme. The chassis should not be your star ground point. The circuit ground should be isolated from the chassis. I suspect your excess white noise is coming from this.
If your attenuator is a true ladder type then you dont really have balanced inputs as that would require an 8 section switch. I suppose you have a 4 pole series attenuator.
An output attenuator is more easily done with a relay unit such as a Dantimax attenuator. They are not too expensive.
Generg, you beat me to it.
I do not know this attenuator, so please tell me exactly what are the codes of the kits that I have to buy (if you can show me the link on the site) and how do I connect them together, thank you very much.
Gianni
You have to order from this side
Dantimax (elektronik) - Control_boards
The VolControl1 If you want no display 17€.
And from this side
Dantimax (elektronik) - Selectors_-_attenuators
RelVol3. 47€
And the 1k resistor set , there seems to be no Dale set any more, it is a good metal film set. 3€
And a power supply psu1
Dantimax (elektronik) - Power_supply_kits
26€
And if you want a remote
Dantimax (elektronik) - Accessories
And do not forget to ask Mikkel if your order is correct and complete... Before you pay.....
I did not understand what parts were needed and ordered three times! Save money and ask him....
Components are really good!
I viewed the link you provided me and I seemed to understand that just buy the kit RelVol3 kit with two 1K resistors kit (balance adjustment) and its respective PSU 5V to get the volume control;
you should not need the kit VolControl1 you've shown me,, am I right?
Gianni
p.s.: and if I using a four-section model ALPS potentiometer with a value of 5K,,, would be fine?
you need also the Kit Volcontrol1, it has the rotary encoder and the eye for the remote, RelVol3 makes only the attenuation.....
you see the site is not self explanatory...
better ask Bill...for the second point concerning the Alps pots....
i suppose it will work also...... but you must have a higher input impedance of the following outputstage...
and the 1k network does more damping to the circuit, but I do not know how important this aspect could be.....for the sound......
you see the site is not self explanatory...
better ask Bill...for the second point concerning the Alps pots....
i suppose it will work also...... but you must have a higher input impedance of the following outputstage...
and the 1k network does more damping to the circuit, but I do not know how important this aspect could be.....for the sound......
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