Pass Aleph P1.7 Help needed

[fschlenk]

Hi all,

i am currently building an Aleph p 1.7 clone.
PCB comes from http://web.vip.hr/pcb-design.vip/aleph-17.html

Test show that the amplification is not working properly:
With an input voltage of 450mV I get 1.05 V output max.
I tried all Input Switch Positions.
The 9610 are running very hot (85 degree C).
Does anyone who already built an Aleph P 1.7 have the voltages over Mosfeet and Bipolar Transistors and can send these value to me.

Any help is highly appreciated.

Thanks and All the best

 

[acaudio]

For first you should measure the voltage loss across the source resistors (22 respective 33 Ohm)
The voltage loss should be at aprox. 0,65V

Adam

 

[jleaman]

Remove the . from the end of your link .. : O )

http://web.vip.hr/pcb-design.vip/aleph-17.html



J'

 

[fschlenk]

For first you should measure the voltage loss across the source resistors (22 respective 33 Ohm)
The voltage loss should be at aprox. 0,65V

Adam

Hi acaudio,

the voltage across the source resistors is 0.62 and 0.66 V.
Any other ideas ?

Thanks

 

[acaudio]

Hi acaudio,

the voltage across the source resistors is 0.62 and 0.66 V.
Any other ideas ?

Thanks

Hello,
which value of gain potentiometer has you used?
2K as in original?

Regards
Adam

 

[fschlenk]

Hello,
which value of gain potentiometer has you used?
2K as in original?

Regards
Adam

Hi Adam,

I tried with the 2k pot. But the amplication is not affected by the setting. Now I use 768R fixed.

Regards

 

[aht]

Do you want my PCB

Give me your PCb design or post it here.

I'll be compare & check PCB line. You may be get a wrong design of PCB.

Now I use AlephP1.7 ,too.

It's sound nice with Evox capacitor 12uF*8/63V.I'll be compare with Panasonic FC series soon.

If you want my PCB's design & bias test point can email me for send it.

Regard
AHT

 

[kilowattski]

AHT,

He is using a proven PC board. If you read his first post you will see he is using a PC board designed by Kristijan Kljcaric of PCB-DESIGN. The boards have been used successfully by many members of this forum.

 

[kilowattski]

fschlenk,

If you are using an attenuator or potentiometer on the output please disconnect it then remeasure the gain. Remember that the output is 1/2 if your are using the single ended input. If you are using single ended input remember to short the negative input to ground. Also remember that the internal attenuator switches need jumpers in position 1,2,7,8 and 3,4,5,6 should be open for zero dB input attenuation.

 

[jh6you]

If the voltage measures about 0.60-0.7 accross R44/55/59/70 and about 30V at the drains of 9610s. Nothing is wrong.

Mayby Nesson Pass is wrong!!!

Regards

 

[kilowattski]

jh6you,

I agree, it sure looks as if it is working. Thats why I suggested looking elsewhere. I wonder if he forgot the jumpers for the 12 dB input attenuator or has a problem with his output attenuator or a miswire external to the board.

 

[fschlenk]

If the voltage measures about 0.60-0.7 accross R44/55/59/70 and about 30V at the drains of 9610s. Nothing is wrong.

Mayby Nesson Pass is wrong!!!

Regards

Thanks for your help. This is exactly what I meassure. I have approx. 30 V at the 9610 Drain and 60 V at the 9610 Source.
But I can not see an amplification. I used a sine wave 450 mv at the input (single ended) and messured max. 1040 mv at the output (single ended) with the highest amplification set at the input switches.
Why are my 9610s running so hot (85 degree C) ?
I definetly appreciate all ideas !

 

[fschlenk]

jh6you,

I agree, it sure looks as if it is working. Thats why I suggested looking elsewhere. I wonder if he forgot the jumpers for the 12 dB input attenuator or has a problem with his output attenuator or a miswire external to the board.

Hi,

do you mean the switches at the input to set the input resistance ?

Thanks

 

[kilowattski]

The switches do not set input impedance they set input attenuation. If you download the Aleph P 1.7 users manual it tells you how to set the switches.

 

[jh6you]

Why are my 9610s running so hot (85 degree C) ?

I think that it is simply due to the heat sinks smaller than you wanted.

Kilowattski would help you better for other matters. He is an actual user of A1.7.

Regards

 

[Alain Dupont]

fschlenk,

>> Why are my 9610s running so hot (85 degree C) ?

Depends on the heatsinks, I have worked the IRF610 on the CCS-X-bosoz
to about 90 to 100 degree C without any pb... max 150 deg C

Only their life will be shorter !!!

Could use a lot of them for the pizzas!

Regards.

Alain.

 

[fschlenk]

The switches do not set input impedance they set input attenuation. If you download the Aleph P 1.7 users manual it tells you how to set the switches.

Thanks kilowattski,

this is exactly what I meant. Pls. correct me when I am wrong. As think and meassuered that the input impedance is also affected by these switches. With max. amplifaction set at these switches I only get appox. 1 Volt out of 450 mV.

Thanks

 

[SDF]

Yes that right, it's change the input impedance.

So, you mustn't switch on all together. whatever, the input impedance is too low.

Download the user manual, nothing mentioned about impedance but in all case, never under 10K, no problems for source.

 

[spence]

Not to hijack this but since we're on the subject...

Can anyone tell me what impedance attenuators go on the output of the Aleph P 1.7... specifically if I want to build based on Kristijan's PCBs.

Thanks!!!

-Spence

 

[kilowattski]

SDF,

Wrong, Wrong, Wrong. SDF please look at page 2 of the service manual. Nelson outlines the setting of the switches for various attenuator settings.

The input pad settings are as follows (only 3 settings)

1.3 dB......3,4 5,6 on
9.7 dB......ALL OFF
15 dB.......1,2 7,8 on

Nelson please forgive me for coping the above sentence from your service manual.