I have already given Gerber files to Sachin.
This is layout which I designed couple of months back.
And this is where I used it after selected source and before Pass B1
Pass B1
- Thread starter sachu888
- Start date
This is layout which I designed couple of months back.
And this is where I used it after selected source and before Pass B1
Hmm, you guys are using an active preamp and providing gain to the signal and then using the LSA to again limit the gain to control volume.
Noob question here. Is it not better to take the signal from the source straight to the B1 and then take it to the active preamp?
Either way will do, but B1's output impedance is exact 50 ohm, ideal for audio RCA cable, same thing is not true for active SSP. So B1 will drive any power amp happily while both can sever good input buffer near source. Only LSA lowers impedance if visible to source.
bhaskarcan
Well-Known Member
Great job my friend....very soon I'm lugging the F5 to your place (health tonic is on you)
I'm eagerly waiting for the day. And don't worry about the health tonic, you will be 'served'
:lol:Bhaskar
bhaskarcan
Well-Known Member
Hey Bhaskar, congrats on the build. The Wooden faceplate looks great.
............
How did you affix the Aluminum pieces? Could you post a close up pic?
Hello Captain,
Here are the close up pics.
Thanks & Best regards,
Bhaskar
Ok what is its OP impedance?
I had recently connected my Marantz CDP to my class D power amp through the LSA. Music came through but when I increased the volume control beyond 90%, the amp went into protection mode. Did I do anything wrong?
Somewhere it was documented ~70 ohms.
No it's perfectly okay as you fed your power amp till it went into satuaration and subsequent protection. Maranz CDP has output level higher than other sources. Either reduce gain of amp kit if provided or leave it like that. [Adding 12K in LSA input is not so good solution as it will reduce gain to half for all sources.]
Actually, I intend to make a B1 and mate it to Class D power amp. I also wanted to make the power amp with two options:-
1. To be used directly as a power amp.
2. To vary it's gain by routing the input through an LDR through a second set of RCA plugs.
I haven't thought about this impedance matching thingy. Do you think that the idea is workable?
1. To be used directly as a power amp.
2. To vary it's gain by routing the input through an LDR through a second set of RCA plugs.
I haven't thought about this impedance matching thingy. Do you think that the idea is workable?
Not sure whom you are referring to but coming right after my post, I presume it is my post.
LSA, (Light Speed Attenuator) or LDR (Light Dependent Resistor) is a wonderful way of getting a potentiometer out of the signal path.
I'm unable to understand how it is "supposed to be used with two preamps"
Pot used as volume control has general values above 47K, which is impedance source sees. Here two LDRs in series and shunt operated as volume control shows ~13K which should be ~25K.
Two preamps means two buffers? IMO it look like you are referring both buffers as preamps. That is good idea.
Om,
Can you post the final schematic of SSP that you built? I saw some posts on audiokarma where you stated that you got rid of output coupling caps.
I am planning to build this by point to point wiring. Do you think this will work fine? Cause the circuit seems to be pretty simple and will be powered by the Pass B1 power supply.
Thanks
Can you post the final schematic of SSP that you built? I saw some posts on audiokarma where you stated that you got rid of output coupling caps.
I am planning to build this by point to point wiring. Do you think this will work fine? Cause the circuit seems to be pretty simple and will be powered by the Pass B1 power supply.
Thanks
sachu888
Well-Known Member
Yes its a very easy circuit.FM Murli has built it point to point.He prefers it over his Marrantz http://www.hifivision.com/phono-turntables/20115-batery-powered-diy-cnc-phono-stage-37.html
I have few PCbs for this in case if anyone wants I can also offer full kit.
Regards,
Sachin
I have few PCbs for this in case if anyone wants I can also offer full kit.
Regards,
Sachin
Hey Sachin, I want one. Since my B1 cabinet's faceplate screws are about to be despatched by Magma, I'll be building it soon. Send me the kit ASAP. Tell me the amount to be transferred.
You can easily build it on temporary board as shown in above PCB. If you add 1M, 1/4W resistor from input to ground then output DC offset is 0.3mV for AD823 OPAMP which I tested. That makes 2.2uF caps redundant and can be omitted.
BTW, you need to supply dual PS (+,0,-) to this where Pass B1 has single PS rail (+,0).
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keith_correa
Well-Known Member
Count me in for a full kit of the SSP too.
sachu888
Well-Known Member
Sure,I will start a new thread for this.I need to order few PCBs for this.
Regards,
Sachin
gans
New Member
Sir, since I'm a complete noob, can I also tag along?
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