Coreyk78 said:I put the russian cap under the board
I've been playing with some 1000pf teflons also as seen in the picture 😀
Coreyk78:
Thanks for the great picture. Now it looks like I'm going to need some longer (or taller) standoffs.
🙂
ClaveFremen said:
I need to clarify because I think that my post could be somewhat confusing in some parts...
I'm not saying that the 'right' sound is the one in the bathroom or the one were voices and instruments are 'thinner' nor that other positions don't influence sound 😉
C21 has no effect on the work done by C6,C11 and their bypasses but if a particular cap in C21 or others position retains the good of the C19,C20 mod and makes voices and instruments more spot-on that cap must be used. 😀
For instance Silmics in C6, C11 do exactly that: voices and instruments are more focused, dinamyc increase, bass is tighter and the "Basically its like I turned the volume down on the sounds that happen in the very middle of the soundstage." that Uriah reported disappear; greater transparency and better soundstage obtained from C19,C20 removal are preserved too. 😎
Each cap and it's bypass (or no bypass at all) must be evaluated together, IMHO
Another example is the value of 22nF for C21, until you replace BQ in C21 you don't notice that silly coloration reported by Tom since soundstage deepness is flat compared to MKS2/MKP2/FKP2... 😀
That silly coloration is particularly present with Silmic in C9 but also FMs are affected and benefits from the 22nF bypass...
This amp seems each day more an elaborated recipe
Well, I am moving to Texas to an apartment for a while til we find a house. Maybe this is the kind of stuff that will keep me busy.
Dario yes you are right I miss the body that was there but what bothers me most is the smaller soundstage. I am a sucker for imaging 🙂 But it certainly sounds better than with those caps.
Uriah
Dario yes you are right I miss the body that was there but what bothers me most is the smaller soundstage. I am a sucker for imaging 🙂 But it certainly sounds better than with those caps.
Uriah
Dario,
What value cap are you using for C7? I see that, like all the other bypass caps, it was originally specified (and silkscreened) to be 100nF, but, like almost all the other bypass caps, it became 220nF at some point. I know that's what is on the latest TP BOM, so it's not the fault of the kitmen. With all this discussion regarding appropriate value of C21 (and it seems that smaller is better, at least there), I wonder if the 220nF value is too high for C7 and possibly others. Can anyone determine at what point the original value 100nF turned into 220nF and why?
Peace,
Tom E
What value cap are you using for C7? I see that, like all the other bypass caps, it was originally specified (and silkscreened) to be 100nF, but, like almost all the other bypass caps, it became 220nF at some point. I know that's what is on the latest TP BOM, so it's not the fault of the kitmen. With all this discussion regarding appropriate value of C21 (and it seems that smaller is better, at least there), I wonder if the 220nF value is too high for C7 and possibly others. Can anyone determine at what point the original value 100nF turned into 220nF and why?
Peace,
Tom E
udailey said:
Uriah the body problem can fixed swapping FMs with Silmics in C6 and C11.
Regarding the soundstage problem in my setup I'm having different results and the unique difference is C7 since I've done my tests with FMs, mine is a Wima MKS2 but i think that MKP2 would be the same if not better.
madisonears said:
My C7 is a 220nF Wima MKS2 and it's soldered since the initial build.
I'm not having problems at all with that cap but next time I turn on my solder iron I could socket also C7.
Really good news and really, really bad news.
Yesterday I received 220uF Blackgate standard caps for C9 and WIMA 0.022uF caps for C21. Installed both in one monoblock, then removed C17 and C18. I had already removed C19 and C20 and I liked what it did to the sound.
Hooked it up and, after about an hour, the sound was absolutely gorgeous. So sweet and solid and detailed, three dimensional, no weird coloration whatsoever. Absolutely the best I've heard yet from these amps, even with the other monoblock unchanged.
Today I made the identical mod to the other monoblock without any difficulty. Plugged it in, turned it on, heard the relay click. Hooked up the input and speakers, turned it on again, heard the relay click but no music. Turned it off, checked the wiring outside and inside the amp (cover still off). Turned it on again, thought I heard the relay click but I'm not certain. Looking closely at the circuit, then I see a beautifully intense, little orange spark and a tiny wisp of smoke near C10 and the LM318. Turned it off immediately.
There doesn't appear to be any damage to any components. I haven't tried anything yet because I don't know what to do. Any ideas? I am not a technician, so please make some suggestions where to start troubleshooting.
I was so close, and now I am thoroughly bummed.
Peace,
Tom E
Yesterday I received 220uF Blackgate standard caps for C9 and WIMA 0.022uF caps for C21. Installed both in one monoblock, then removed C17 and C18. I had already removed C19 and C20 and I liked what it did to the sound.
Hooked it up and, after about an hour, the sound was absolutely gorgeous. So sweet and solid and detailed, three dimensional, no weird coloration whatsoever. Absolutely the best I've heard yet from these amps, even with the other monoblock unchanged.
Today I made the identical mod to the other monoblock without any difficulty. Plugged it in, turned it on, heard the relay click. Hooked up the input and speakers, turned it on again, heard the relay click but no music. Turned it off, checked the wiring outside and inside the amp (cover still off). Turned it on again, thought I heard the relay click but I'm not certain. Looking closely at the circuit, then I see a beautifully intense, little orange spark and a tiny wisp of smoke near C10 and the LM318. Turned it off immediately.
There doesn't appear to be any damage to any components. I haven't tried anything yet because I don't know what to do. Any ideas? I am not a technician, so please make some suggestions where to start troubleshooting.
I was so close, and now I am thoroughly bummed.
Peace,
Tom E
madisonears said:
I'm sorry to hear that from you!
First make a visual check of the area interested by the soldering activity seeking bridges of solder between traces or things like that.
If all seems ok then check with a multimeter if PS voltage around LM318 is ok (probably it's burnt, originally it was reccomended to mount it on sockets since it is very sensitive to ESD).
I hope that you find promptly the fault.
Good luck!
Thanks, Dario.
Made another visual inspection and I found what might have been a small solder bridge from hot to ground near where I installed C21 from the bottom of the board. I think solder bridged the small gap that separates the pad on top of the board from the ground plane. I used a small grinder to remove that. With the board hanging loose of the enclosure, I plugged it in and got the relay to click. I hooked up a test speaker and got music. Put the board back into the enclosure and saw another spark in a different place. No music.
There is no part of the circuit contacting the enclosure other than the chip to the heatsink, which is insulated. It is mounted and connected in the same manner as the other amp, which works fine. I'm stuck.
Peace,
Tom E
Made another visual inspection and I found what might have been a small solder bridge from hot to ground near where I installed C21 from the bottom of the board. I think solder bridged the small gap that separates the pad on top of the board from the ground plane. I used a small grinder to remove that. With the board hanging loose of the enclosure, I plugged it in and got the relay to click. I hooked up a test speaker and got music. Put the board back into the enclosure and saw another spark in a different place. No music.
There is no part of the circuit contacting the enclosure other than the chip to the heatsink, which is insulated. It is mounted and connected in the same manner as the other amp, which works fine. I'm stuck.
Peace,
Tom E
arrgh...having problems finding good pair of heatsinks. Isn't there someone on ebay who sells a bunch of sizes of extrusions in cut to order sizes? I searched here and on ebay, but couldn't find what I had seen before, and I'm pretty sure someone here posted a link a few months ago
Try this......
http://shop.ebay.com/merchant/barrredboss_W0QQ_nkwZQQ_armrsZ1QQ_fromZQQ_mdoZ
I'd ordered from him before......
Farley
http://shop.ebay.com/merchant/barrredboss_W0QQ_nkwZQQ_armrsZ1QQ_fromZQQ_mdoZ
I'd ordered from him before......
Farley
Heatsinks
This is almost exactly what I use. They hardly get warm.
http://www.newegg.com/Product/Product.aspx?Item=N82E16835200042
I have 95db/SPL 8Ohm speakers. I think that matters since I dont need many watts to push them. But based on how warm these get I would think that even 85+db/SPL speakers would be fine.
Uriah
This is almost exactly what I use. They hardly get warm.
http://www.newegg.com/Product/Product.aspx?Item=N82E16835200042
I have 95db/SPL 8Ohm speakers. I think that matters since I dont need many watts to push them. But based on how warm these get I would think that even 85+db/SPL speakers would be fine.
Uriah
madisonears said:
You're welcome Tom,
since the module seems to work if not mounted to the enclosure, to me it looks like the insulation, that is essential, is not good any more...
Sometimes the simplest things cause the biggest problems.
I made some adjustments to the board mounts, and the amp seems to work again. There was a lot of mechanical stress on the 3886 leads due to coupling unevenly to the heatsink and I believe that caused some part of the circuit within the chip itself to become open or closed. Now there is more DC offset, however, and I wonder if the 318 was damaged by all that sparking. This circuit is tough but not indestructible.
Right now, it's playing through the cheap test speaker, so I don't know if fidelity is affected. I'm going to let it run a bit and then hook up the main speakers if nothing gets too hot or otherwise malfunctions.
Peace,
Tom E
I made some adjustments to the board mounts, and the amp seems to work again. There was a lot of mechanical stress on the 3886 leads due to coupling unevenly to the heatsink and I believe that caused some part of the circuit within the chip itself to become open or closed. Now there is more DC offset, however, and I wonder if the 318 was damaged by all that sparking. This circuit is tough but not indestructible.
Right now, it's playing through the cheap test speaker, so I don't know if fidelity is affected. I'm going to let it run a bit and then hook up the main speakers if nothing gets too hot or otherwise malfunctions.
Peace,
Tom E
Just hooked up the main speaker, and there is low level hum, below level of most music, but clearly audible, unaffected by volume control. Speaker "snapped" when relay clicked, so I know there is DC present.
Other amp: stone silent, playing beautifully.
Any suggestions?
Peace,
Tom E
Other amp: stone silent, playing beautifully.
Any suggestions?
Peace,
Tom E
I suggest to firm up all of your grounding again. Every time I get DC offset its because I messed with the amp, moved wires around, and have a ground wire a little loose.
Uriah
Uriah
Uriah,
Good suggestion, but there's no real ground connection to the board except the 0 volt line from the xformer. I have a safety ground for AC line, of course, and the speaker and input grounds, and those are all fine. Other than the hum, music plays fine (although it seems somewhat bright, perhaps even distorted, from the bad channel. Is that an effect of excess offset? Or is something else wrong?). There seems to be no reduction of output power, and heating is normal.
On the bad channel, I am also getting a serious pop through the speaker whenever my furnace blower motor starts, and that has never happened with any other electronics.
I think I busted something. Perhaps the 318, perhaps the 3886, perhaps the rectifier. I will start replacing stuff until the hum goes away, unless someone has any other ideas.
I can figure out the 318 and 3886 just fine, but the rectifier gets a little confusing because of all the letter codes behind the part number GBJ1504. Can you please tell me exactly which rectifier part number is it, and where did you buy them?
One thing I will state for sure: I like the Blackgate and even the Panny FM at C9 a lot more than the Silmic. The Silmic seemed to suffocate the highs and upper mids and even affect vocals. Sometimes I would walk into the room with music playing and wonder if my tweeters were working! Sorry, Dario, but I think it's a bad choice for this amp.
Peace,
Tom E
Good suggestion, but there's no real ground connection to the board except the 0 volt line from the xformer. I have a safety ground for AC line, of course, and the speaker and input grounds, and those are all fine. Other than the hum, music plays fine (although it seems somewhat bright, perhaps even distorted, from the bad channel. Is that an effect of excess offset? Or is something else wrong?). There seems to be no reduction of output power, and heating is normal.
On the bad channel, I am also getting a serious pop through the speaker whenever my furnace blower motor starts, and that has never happened with any other electronics.
I think I busted something. Perhaps the 318, perhaps the 3886, perhaps the rectifier. I will start replacing stuff until the hum goes away, unless someone has any other ideas.
I can figure out the 318 and 3886 just fine, but the rectifier gets a little confusing because of all the letter codes behind the part number GBJ1504. Can you please tell me exactly which rectifier part number is it, and where did you buy them?
One thing I will state for sure: I like the Blackgate and even the Panny FM at C9 a lot more than the Silmic. The Silmic seemed to suffocate the highs and upper mids and even affect vocals. Sometimes I would walk into the room with music playing and wonder if my tweeters were working! Sorry, Dario, but I think it's a bad choice for this amp.
Peace,
Tom E
Tom, I will stick to my guns on the grounding. Until I fixed my grounding I had such a huge pop at turn on that I bought an enormous power conditioner from Audiholics to silence the pop. (the pop was from a certain lighswitch in the house that later shot sparks at me and also from the fridge turning on and off) It helped a little as it has its own ground which I connected to, but what was wrong was that I was not soldered onto the binding posts for my amps output. I had the wires screwed into the posts because they are huge and wont heat up enough with my iron to melt the solder. Anyway, when I went through each and every wire that goes to any ground and made sure there was a solid connection it got quiet. And.. while the amp has only the 0V ground there is also a signal ground going to it from the RCA and there is speaker ground coming from it to the speakers. I had it wired normally then added a wire from signal ground on the board back to the RCA ground. I then took a solid copper 24awg bare wire from RCA ground to RCA ground to speaker ground to speaker ground to chassis ground. I then took 0V from the toroid and ran a small wire from there to chassis ground. It works and its silent. However, it I get in there and goof around every single time I get the hum back and I am not soldered on most ground connections so this is my problem. They usually stop making good contact and need to be reseated properly. Honestly if you reseat all your grounds and make sure the connection is great then I bet you will have success.
Same experience I had with the Silmics. Right now with a Lightspeed driving the amp and C13 and the 2 200nf caps removed I am very pleased. Maybe more tweaking once I get settled in Texas. We move Thursday and I am sore, tired and full of complaints as normal 🙂
Uriah
Same experience I had with the Silmics. Right now with a Lightspeed driving the amp and C13 and the 2 200nf caps removed I am very pleased. Maybe more tweaking once I get settled in Texas. We move Thursday and I am sore, tired and full of complaints as normal 🙂
Uriah