| acaudio |
Hi,
my first aleph plays music :D
Greetings
Adam |
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| Duck-Twacy |
Very nice.
What PCBs are you using?
Still pondering wether I will make me an Aleph pre or buy me a secondhand X2.5 one day |
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| acaudio |
The PCB´s are my own design, made for the wima mkp4 10µF capacitors. Size 160x100mm single-sided.
Power supply are 100x75mm (2x 60V) with 80VA transformer.
thx
Adam |
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| JasonL |
| nice work .. Keep it up : O ) |
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| MikeW |
| Nice boards. What do you have planned for the housing? |
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| acaudio |
19" housing with a sanded aluminium surface and steinless steel buttons will be nice, but this is a long way...
thx
Adam |
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| Jean |
| Very nice, how does it sound ? Do you have other preamps you can compare this to side by side ? |
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| acaudio |
I listened so far with direct connection CD to my power amp (selfmade like Thel), see my homepage http://www.acaudio.de (under construction). I will compare this with another preamps when the relay volume control works. With headphones sounds smooth and sweetly but these have only 75 ohms impedance.
thx
Adam |
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| acaudio |
Hi,
the relay volume control like aleph p1.0 (with adc0804) works. :)
Problem:
between step 32 (relay 1-5 on, relay 6 off) and 33 (relay 6 on, 1-5 off) gives it pop noise. Only with signal.
anybody an idea? :confused:
thx
adam |
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| HBarske |
You have already found the reason for the problem:
This happens when all te relays are switching at once - this generates a very short "level step".
One proven method to get rid of that requires the presence of a "mute relay" on the output and some additional circuitry (microcontroller to be preferred): just switch the mute relay on just before the volume control makes "the evil step". If you play a little with the delay times, you might get this solution working without audible effects. |
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| acaudio |
Hello Holger,
thanks for your replay. How is your new LP?
I would like to do this without microcontroller.
I have already by parallel connection of a 1k resistor at the exit of the circuit a clear improvement reached. The gain is a little lower, but it works good.
I like this Aleph sound, i have today removed the input capacitor from the power amp , it sounds very good with much more detail and dry bass...
Now i need a housing.
greetings
Adam |
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| Stabist |
Great looking AP!
Btw - the "bottom" (3rd one) pdf is not working (at least in my case :bawling: )
How exactely did you do your PCB?? Are they milled?
Btw - your amplifier - how hot does it get - and do you find the copper plates with transistors mounted on it as a good solution or not?? |
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| choky |
| quote: | Originally posted by acaudio
Hi,
the relay volume control like aleph p1.0 (with adc0804) works. :)
Problem:
between step 32 (relay 1-5 on, relay 6 off) and 33 (relay 6 on, 1-5 off) gives it pop noise. Only with signal.
anybody an idea? :confused:
thx
adam |
try with elco in paralel with some relay coil;
that will give ya small delay
mebbe it will work
:smash: |
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| acaudio |
| quote: | Originally posted by Stabist
Great looking AP!
Btw - the "bottom" (3rd one) pdf is not working (at least in my case :bawling: )
How exactely did you do your PCB?? Are they milled?
Btw - your amplifier - how hot does it get - and do you find the copper plates with transistors mounted on it as a good solution or not?? |
uups ;)
http://www.acaudio.de/aleph_p17_bottom.pdf
/Adam |
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| acaudio |
| quote: | Originally posted by Stabist
...How exactely did you do your PCB?? Are they milled?
Btw - your amplifier - how hot does it get - and do you find the copper plates with transistors mounted on it as a good solution or not?? [/B] |
The pcbs are Bungard FR4 singlesided.
The photoplots are printed on transparece paper with laser printer. Exposed with UV light and developed with NaOH. Pcbs is normally atched at 50°C witch sodium-per-sulfate .Then drilled and afterwards still times full-laminar exposed and developed with NaOH.
For last soldermask painted (Contact).
The Fets runs hot, aprox. 70°C without heatsinking, 65° with. With copperplate these are optimal thermal coupled. A simple thermal coupling in pair isn´t available then this layout is nearly point-symmetric, so are all coupled, both channels an one copper plate. and this looks pretty. I like copper then this is nearly double thermal conductive as aluminium.
sorry for my bad english :xeye:
/adam |
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| acaudio |
| quote: | Originally posted by HBarske
...If you play a little with the delay times, you might get this solution working without audible effects. [/B] |
This works GOOD!
Danke Holger!
| quote: | Originally posted by choky
...try with elco in paralel with some relay coil;
that will give ya small delay
mebbe it will work
:smash: |
The relay coil has 320OHM/2=160Ohm -> For delay aprox.0,1s you need a capacitor ~625µF and have almost short by off->on switsching.
I added a 1µ capacitor at basis, and this works pretty.
The resistor parallel to output is now removed.
thx
Adam |
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| Clarkcr |
Where is the universal ground? Doesn't the circuit need a ground?
Nice looking setup.
C |
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| acaudio |
| quote: | Originally posted by Clarkcr
Where is the universal ground? Doesn't the circuit need a ground?
Nice looking setup.
C |
Hi,
maybe i don´t understand your question.
Ground:
both channels have separate ground.
powersupply too.
The controlboard too.
The volume control relay shared a 12VDC supply and are switched to Control-gnd via transistors, see pic. Left and right channel are not an common ground. As i buy an second transformer, are both channels fully separate.
All pcbs are made with Ground plane at bottom. Maybe is it not a best? But singlesided layout with a straight star ground wirng is not so easy... This should be realise by next project (AX) :smash:
greetings
Adam |
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| Clarkcr |
Okay, I just didn't see where there was a ground anywhere. I always thought there needed to be a star washer type ground.
C |
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| HBarske |
| quote: | Originally posted by Clarkcr
Okay, I just didn't see where there was a ground anywhere. I always thought there needed to be a star washer type ground.
C |
Have a look at the bottom pcb layer. There you'll find the ground plane. It doesn't show in the other PDFs. |
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| rsbay |
Hallo Adam,
nice work !!! I also plan to build an Aleph P. Which type of MOSFET's
you have used in your design ? The original types are not available
at my favorite dealer (Reichelt).
Regards
Ralph |
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| acaudio |
| quote: | Originally posted by rsbay
...Which type of MOSFET's
you have used in your design ? The original types are not available
at my favorite dealer (Reichelt)....
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Thanks Ralph!
Reichelt is too my favorite. ;)
I used IRF510 (SEC) and IRF9610 (Fairchild) both from Reichelt.I bought 50+50 piece , selected these from equally lot and matched in pair to 1mV. See my matching-circuit. At Reichelt you can´t buy a original sealed tube from producer, only mix.
But you can buy more and send what you don´t need back.
thx
Adam |
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| rsbay |
Hallo Adam,
I take a look at the datasheets of the 610 and 9610 at
International Rectifier and I think about giving the 630 and 9630 a
chance. They have nearly the same data's, but the Rds_on of the
630/9630 are a little bit lower. These MOSFET's are available
at Reichelt.
Greetings from Titz
Ralph |
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| uli |
I wouldnt use the 630/9630. In a preamp the Rdson is of no
importance and as these Mosfets are primarily designed as
switches they dont perform too well in an analog circuit.
You may read some of the background literature by NP as well
as the construction articles about A75 by NP and Norm Thagard.
Uli
:nod: :nod: :nod: |
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| acaudio |
| quote: | Originally posted by rsbay
...They have nearly the same data's, but the Rds_on of the
630/9630 are a little bit lower. ...
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Hi Ralph,
Have a look at the in-/out capacitance:
IRF610 140/53pF
IRF510 180/81pF
IRF630 800/240pF :bigeyes:
/Adam |
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| rsbay |
Thanks Adam & Uli,
I only take a look at the current and the channel resistance, but forgot
the capacitance. I will look a second time and also read the articels.
Regards
Ralph |
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| rsbay |
Hello,
I followed your tips and bought IRF610 / IRF9610 (50 pieces each)
at Conrad Elektronik. A little bit more expensive than my prefered
supplier Reichelt, but I get the "original" from International Rectifier.
In the next step I have to select the right MOSFET's for my Aleph P.
Which MOSFET should be equal ? I think the two upper current source
transistors, the two lower current source transistors and the two
amplifier transistors in the middle should have the same values, so that
both sides of the preamp are identical.
Regards
Ralph |
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| jh6you |
If I see mosfet data sheet, the input capacitances are indicated at the conditions of Vgs=0, Vds=25V and f=1MHz. Is this meaning the input capaitances are different also at different frequencies lower than 1MHz? I am wondering because the top audio frequency is considered at about 20kHz.
Hmm... IRF240 has the input capacitance of 1275pF at the above conditions. :bigeyes: |
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| acaudio |
| quote: | Originally posted by jh6you
If I see mosfet data sheet, the input capacitances are indicated at the conditions of Vgs=0, Vds=25V and f=1MHz. Is this meaning the input capaitances are different also at different frequencies lower than 1MHz? I am wondering because the top audio frequency is considered at about 20kHz.
Hmm... IRF240 has the input capacitance of 1275pF at the above conditions. :bigeyes: |
Hi,
at higher capacitance you need more current to change voltage level at the gate (music signal). Therefore you need a driver before high power FETS.
/adam |
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| acaudio |
| quote: | Originally posted by rsbay
...I think the two upper current source
transistors, the two lower current source transistors and the two
amplifier transistors in the middle should have the same values, so that
both sides of the preamp are identical.
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this is too my opinion.
/adam |
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| Nelson Pass |
| quote: | Originally posted by jh6you
If I see mosfet data sheet, the input capacitances are indicated at the conditions of Vgs=0, Vds=25V and f=1MHz. Is this meaning the input capaitances are different also at different frequencies lower than 1MHz? I am wondering because the top audio frequency is considered at about 20kHz.
Hmm... IRF240 has the input capacitance of 1275pF at the above conditions. :bigeyes: |
Actually, the first Aleph P's used IRF230's which have somewhat
less capacitance than that, and they worked fine. They did
sound a bit different than the IRF610's used later, but I've
never heard anyone express a particular preference one way
or the other.
Remember that the big capacitance figures being quoted are
Gate to Source, whose voltage changes very little. The real
capacitor to watch out for here is Drain to Gate.
:cool: |
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| jh6you |
| quote: | Originally posted by Nelson Pass
The real capacitor to watch out for here is Drain to Gate. |
From your comment, I understand that the concern is capacitance between input and output (as a kind of bypass capacitor). If the amp is Source follower, then to watch out is Source to Gate?
By the way, I played BOZ and BOSOZ with different IRF numbers and, yeah, hardly detected my preference. :)
------
Want to see that John Travolta and Uma Thurman dance Twist of Goldfrapp............ |
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| ToB |
Look good,
From your PDF files, Did you remove R73? |
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| acaudio |
Hi,
R73 is free wired between PSU and PRE.
Regards
Adam |
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| acaudio |
Well at least 95% done ;)
Adam |
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| steenoe |
ACAUDIO, that is magnificent work. It truly looks good.:cool:
Steen. |
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| acaudio |
Thanks Steen!
Adam |
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| Samuel Jayaraj |
From where can I get Aleph P1.7 schematics? I tried to connect to passlabs.com but simply could not. Can someone please, provide a link or post the schematic?
Thanks for the help in advance. |
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| kilowattski |
| Here you go.... |
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| threefff |
Hi acaudio,
that P1.7 really looks great!! Very professional to me. I wish my diy circuits would look as good as yours from the inside.
Have you ever thought of a remote control?
What is on the double decker boards beneath the main boards?
Would you mind sharing their layouts (or did you already?)
Cheers
Thomas |
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| acaudio |
| quote: | Originally posted by threefff
Hi acaudio,
that P1.7 really looks great!! Very professional to me. I wish my diy circuits would look as good as yours from the inside.
Have you ever thought of a remote control?
What is on the double decker boards beneath the main boards?
Would you mind sharing their layouts (or did you already?)
Cheers
Thomas |
Hi Thomas,
a remote control for volume? Should be doable, look at www.schuro.de
The double deckes boards are at bottom source switch (relay) and on top volume board.
For layouts look here: http://www.diyaudio.com/forums/show...0815#post550815
Cheers
Adam |
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| threefff |
Hi acaudio,
I really appreciated the layouts you already posted. I didn't find the relay boards.
Cheers
Thomas |
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| acaudio |
| quote: | Originally posted by threefff
Hi acaudio,
I really appreciated the layouts you already posted. I didn't find the relay boards.
Cheers
Thomas |
www.acaudio.de/rel_control.pdf
/Adam |
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| threefff |
Hi acaudio,
thank you very much.
Right now I also do understand, why you where pointing to Schuro regarding remote control. The program of the 87C750 is unknown, isn't it?
Somehow the power off values of volume und input selector have to be saved (internal EPROM of the controller?) and represented to the latches at power on, right?
Also: the transmitted code of the remote control is unknown, at least to me.
Any ideas? (Yes, use the ADC Volume control....)
Cheers
Thomas |
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| acaudio |
Hi,
I don´t use µC, my volume control works with ADC and Alps motorpot, without remote control.
Cheers
Adam |
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| aht |
http://www.acaudio.de/rel_control.pdf
From page 8-10 of your link does not match with your photo such as Relays 1-6 in volume board but in schematic & pcb there are 7 Relays (1-7)
Why don't use pins 17-18 in IC1 (ADC0804) for increase to 256 steps and use CD4013 for breaking POP-NOISE ?
I have some question with IC4 (4028N) How to connect point 12V/S/A/B/C/D and How it control function "ON" to R2, R22 for switch relay coil K1, K2
Thank for your shared idea :)
REGARD
AHT |
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| threefff |
Hi altogether,
I cought a fever and spend some days in bed. So I had the time figure out the attenuation for each step of the resistor network of the P1.7. See image attached.
From the image it can be seen, why Nelson uses a look up table in the 87C150: only approx. 70 Steps are needed if you want 0,5dB between them (the lowest are fare more aparat, here you find 3 to 4 dB spacing between them).
If you want a curve without jumps (stetig), you need to have your resistors in powers of 2 of the smallest value you are using. The absolute value doesn't care, as long as you are not looking at the input / output impedances of pre and poweramp (what I did here).
With this limitation 8 bit can only code for a attenuation of 48 dB (as 16 bit do for 96 dB on our CDs).
Have fun
Thomas |
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| threefff |
| and this is the Excel file, for those, who like to play... |
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| acaudio |
| quote: | Originally posted by aht
http://www.acaudio.de/rel_control.pdf
From page 8-10 of your link does not match with your photo such as Relays 1-6 in volume board but in schematic & pcb there are 7 Relays (1-7)
Why don't use pins 17-18 in IC1 (ADC0804) for increase to 256 steps and use CD4013 for breaking POP-NOISE ?
I have some question with IC4 (4028N) How to connect point 12V/S/A/B/C/D and How it control function "ON" to R2, R22 for switch relay coil K1, K2
Thank for your shared idea :)
REGARD
AHT |
Hello,
the relay board´s are newer, with 7 Relays (for next projects). I use at present only 6 of them.
Using of full range (256 bit) has only ~19mV between the steps, this can be unstable. You can try it .
I use a binary switch for source select, 12V at common, ABCD binary, "S" is contact between the steps, the ON function turn the preamp on if any source is selected. No source selected => Preamp off.
R2/C2 and R22/C13 do a little delay.
Greetings
Adam |
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| aht |
Thanks Mr.Adam
Could you send me some photo of binary switch & how to connect "s" at the same time with a/b/c and d
I have some idea (picture) for modify 4028 for increase function
:)
regard
AHT |
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| acaudio |
Hello,
the switch is a ordinary binary switch. Type EBE 46-353.
Pins: 1(S), 2=2^0, 4=2^1, 8=2^2, 16=2^3. (habituation-needily...) :) :confused:
This switch has 16 Steps. In my pre I use only 5 (off + 4 sources) mechanical fixed inside. Pin 1 gives a signal only between steps, this can be usually used for enable/disable selection, I use them, but this can be disconnected, no difference in function. It prevents that the preamp goes off between steps by (very) slow turn.
The same switches are used as gain pots.
This is all, no magic.
;)
Adam |
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| acaudio |
| I forgot the picture |
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| aht |
âËÂ...áÅéǼÁ¨ÐËÒ¨Ò¡ä˹ÅèСêÒº...ÍÔÍÔÍÔ...½ÃÑè§ÍèÒ¹äÁèÍÍ¡
This mean where can I buy this switch ? :bawling: :bawling: :bawling:
I think I maybe have to modify function "ON" and selector A/B/C/D to manual switch :whazzat:
Thank for your quickly reply ;)
Do you like Threshold fet-10HL ?
I cloning PCB & Schematic now it use J-fet differential input and complementary transistor output
Could you agree with me to make a project same p1.7/ksa50/alephx/blz/...? |
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| acaudio |
| quote: | Originally posted by aht
...This mean where can I buy this switch ? :bawling: :bawling: :bawling: ... |
Have a look at:
http://www.ebe-gmbh.de
| quote: | Originally posted by aht
...Do you like Threshold fet-10HL ?
I cloning PCB & Schematic now it use J-fet differential input and complementary transistor output
Could you agree with me to make a project same p1.7/ksa50/alephx/blz/...? |
Keep it up ! :)
Best wishes
Adam |
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| UltimateX86 |
Did somebody test an ALEPH P1.7 with Jfet? (2SK389 & J109)
thx |
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| Dr Harley |
J fets do not work good! You have to parallel more J fets because of 20mA is too much for one. Even You are increasing the capacitances and de amplification is lower so it does't satisfy.
If You want to improve the Aleph-P then try a nagative powersupply and DC coupling for the input. It is possible to use Cascode cirquit between de drain and current sources to reduce miller effect and increase bandwidth. You have to keep a 20 Volts between source and drain at the IRF610, then it have its best performance (very important) |
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| promitheus |
Very nice looking preamp !
Congradulations !
Check you have mail. |
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| bbakota2000 |
Hi,
If somebody has the artwork of these PCBs it would be very nice if he could send it to me at bbakota2000@yahoo.com. Thanks a lot. |
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