Mint Tin Phono
Bob,
Here is the link to my Webpage. Private email me with contact info and I will send you the prototype - the amp pictured on the original post.
Cheers - ALBQ
http://mywebpages.comcast.net/gillespie147/AlbuquerqueAudio-MainPage.html
Bob,
Here is the link to my Webpage. Private email me with contact info and I will send you the prototype - the amp pictured on the original post.
Cheers - ALBQ
http://mywebpages.comcast.net/gillespie147/AlbuquerqueAudio-MainPage.html
I jumpered the R5 rather insertng the resistor. Okie dokie. Rewired on a new board and I've got sound, just no amplification. Same volume with or without the battery. Voltages measure 4.15 +/- on the pin 4 and 8 of the socket. Well, at least it hasn't gotten hot or melted!! Maybe I had a bad cap (although new) or the new IC is crap.
Hi ya ALBQ,
I jumpered at both R5 locations, left and right, under the R4 location. If I connect my source inputs to the "bent M-shaped" jumpers on the left and right, I get full volume from the source, but no amplification whether the the battery is connected or not. However, if I connect the source inputs (left and right) to the locations noted by Tangent, I get silence. I'm seriously missing something and I just don't see it yet.
I changed to other new caps (still 0.1 uF since bigger won't fit easily), refitted jumpers on a new board, cleaned flux using 91% alcohol, and rechecked my resistors. All measure out as expected.
Thinking that I might have goofed on the input jacks, I checked input and output connections on my alligator clips for left, right, and ground. Again, all is good.
Somewhere out there is an amplified signal just waiting to be heard, I must find it. Frustrated, yes. Discouraged, no. Thanks ALBQ. These little devices can't be that hard to assemble, can they?
Smokehouse Bob
I jumpered at both R5 locations, left and right, under the R4 location. If I connect my source inputs to the "bent M-shaped" jumpers on the left and right, I get full volume from the source, but no amplification whether the the battery is connected or not. However, if I connect the source inputs (left and right) to the locations noted by Tangent, I get silence. I'm seriously missing something and I just don't see it yet.
I changed to other new caps (still 0.1 uF since bigger won't fit easily), refitted jumpers on a new board, cleaned flux using 91% alcohol, and rechecked my resistors. All measure out as expected.
Thinking that I might have goofed on the input jacks, I checked input and output connections on my alligator clips for left, right, and ground. Again, all is good.
Somewhere out there is an amplified signal just waiting to be heard, I must find it. Frustrated, yes. Discouraged, no. Thanks ALBQ. These little devices can't be that hard to assemble, can they?
Smokehouse Bob
Plot thickens
Bob,
For what its worth, I have made several versions of the CMoy headphone amp on perf pcb and always struggle. Although I can get the things to work, space is tight and I find it difficult to make sure all of the connections are correct. This circuit has even more parts in the feedback loop (riaa filter) so, more difficult still. That is why I made a pcb. Mush easier to get right and still keep the overall footprint down. Do you know how to use or have access to a scope? Makes troubleshooting analog signals musch easier. Sorry cannot be of more help -ALBQ
Bob,
For what its worth, I have made several versions of the CMoy headphone amp on perf pcb and always struggle. Although I can get the things to work, space is tight and I find it difficult to make sure all of the connections are correct. This circuit has even more parts in the feedback loop (riaa filter) so, more difficult still. That is why I made a pcb. Mush easier to get right and still keep the overall footprint down. Do you know how to use or have access to a scope? Makes troubleshooting analog signals musch easier. Sorry cannot be of more help -ALBQ
Those comments are spot on! I recently passed on a scope locally for $25 (won't do that again!). I'll revisit the schematic and components again, paying special attention to values listed by Tangent, and then slowly assemble the parts. My solders look to be complete and clean with no runover or general slop. I went light the first couple of times and can now see where that would be wrong. I'm learning a lot more and looking for the successful end product. Thanks! 
I started fresh tonight, all new components and board. I got a much better IC socket, new caps, the whole shooting match! I am pleased to say I have amplification in the right channel. Left channel is still silent. I have resoldered, rechecked layout and it still only gives me any sound (unamplified) by connecting the input to the "M jumper". We're getting close, I believe.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.