[Coreyk78]

well I redid my signal wiring in a more permanent fashion so it wasn't just hacked in there and my hum is all but gone, I can only here some PS noise at full volume. I still have the clipping on the HP output and the turn off popping issue to deal with though.

 

[digger945]

That may be all you can do with the transformer in the same case Corey.
Good to hear from you and to see your making progress. Have you any listening impressions for us yet?

 

[Coreyk78]

So far I'm very impressed with the sound, I thought my old beresford design TC-754 preamp was pretty good, but I can honestly say the Aikido blows it away. The sound is very detailed, smooth and natural. I also just finished building a VSPS phono pre so I could take the old preamp out of my system completely, the VSPS and Aikido really seem to work well together, my vinyl never sounded so good. The gain is a little high when listening to CDs from my PS one and playing through my chipamp, I can't turn it up very far before its too loud for me. But it works nicely with the VSPS since that is set up for 40db gain. The gain will probably be a good thing when I'm finished building my SimpleSE tube speaker amp.

I figure the HP out clipping isn't a big deal, because regardless of which impedance cans I use the clipping only happens at ear-bleeding levels anyway, hehe.

I'm pretty happy for now, I'll either have to always remember to turn off my amps and unplug my cans before I shut off the Aikido unless I can find a soft start circuit that can handle 170 volts.

Much thanks for so much help from the people in this thread, especially digger945, looser101, and boilermakerfan.

 

[digger945]

I'm happy to see you finally enjoying it. I keep going back to mine whenever I need a fix. I listened to each half of my almost completed Dynamite and my first impression is that the Aikido has way more atmosphere to it. We'll see what happens when it's finally completed. After the meet this weekend I plan to begin the 6H30. I will see what I can find with regards to the turn-off pop and the clipping.

 

[Coreyk78]

I wanted to add that my best grounding results came when I ran the input grounds from the rca jacks to the pot, and then from the pot to the input gnd pads on the pcb. Also I ran the power supply ground to the Aikido PCB and installed the ground jumper on the PCB using the mounting hole and standoff as my star ground point.

I'm going to try a redo of my power supply, I should be getting another choke today, along with some smaller 220uF caps and I'm going to try a CLCLC setup, with 220uF for C1 and C2, and 1000uF for C3.

 

[looser101]

Quote:

Originally Posted by Coreyk78 /img/forum/go_quote.gif I wanted to add that my best grounding results came when I ran the input grounds from the rca jacks to the pot, and then from the pot to the input gnd pads on the pcb. Also I ran the power supply ground to the Aikido PCB and installed the ground jumper on the PCB using the mounting hole and standoff as my star ground point. I'm going to try a redo of my power supply, I should be getting another choke today, along with some smaller 220uF caps and I'm going to try a CLCLC setup, with 220uF for C1 and C2, and 1000uF for C3.

You might want to try the 0.1uF cap and 10ohm resistor in parallel where you put the ground jumper on the PCB. Did you twist the grounds and signal wire together? ie. One signal + one ground twisted together, repeat for each signal wire? If you move those wires around and the hum changes then you might want to get some small diameter coax. I've used RG-174 and it worked great.

The all tube Aikido is probably the most docile pre/amp I've ever used for startup and shutdown. The music just fades in or out, no thump whatsoever.

A tip for you if you don't have a scope....download a tone generator or individual tones of 60Hz and 120Hz. Play them and compare to the hum you hear. If 60Hz then it's probably AC pickup from the AC input or transformer. Or possibly a ground loop. If 120Hz then it's a PSU problem.

Keep at it, it will all be worth it.

 

[Coreyk78]

I think the signal wires are pretty good, the hum at listening level is gone now, I can hear a very faint background hiss if I put my ear close to the speaker. The only time I hear significant noise now is when the volume is maxed without anything playing. But at that level the speakers would probably be distorting and smoking anyway, hehe.

I'm kind of thinking now that I should have just used a standard 9-pin board and used OPTs for headphones, would probably have been simpler. I still don't have bleeder resistors on the power supply caps, I wonder if that could be giving me the pop? I have some 300k 2W resistors I could use, I'd just need to install them from + at the cap to the ground rail right?

I'm also going to change the rectifier diodes from 1N4007 to MUR860. I made that change on the power supply for my VSPS phono-pre and it made a huge difference, my phono stage is very quiet and hum-free.

 

[BoilermakerFan]

Quote:

Originally Posted by Coreyk78 /img/forum/go_quote.gif I'm pretty happy for now, I'll either have to always remember to turn off my amps and unplug my cans before I shut off the Aikido unless I can find a soft start circuit that can handle 170 volts. Much thanks for so much help from the people in this thread, especially digger945, looser101, and boilermakerfan.

Been out of touch of late. Laid off for a month now and just been busy working on my shop area. Tied in the lights today to the main basement lighting circuit. Nice to have 12,000 Lumens of light in a 42 sq. ft. area.

The soft start circuit can be adapted from Ti's design like Colin did, or better yet, use the MHM schematic and just hit cetoole with a PM before you do... I'm pretty sure the coil on the Omron relay is 24VDC, but it should be able to switch higher voltage. You might have to use a similar, but higher rated relay. I know they make 240VAC relays. I have a big ass solid state relay with 24VD inputs, but it's huge and probably cost $$$. It's big enough to switch on full size refrigerators. I'll do a little homework on Peter Daniels thread on diyAudio. I know he really likes a certain line of Panasonic relays and they are about $6 each. Planned to upgrade my Darwin, but then decided the stock relays were fine for the console and now I won't need another Darwin for my other MAX build since the V1.2 is being built with dual inputs stock. I can add a DPDT to bring in a third and keep it simple.

Here's pics of the "shop" area. Receptacles will be live tonight and I'm finalizing my workbench design this week so I can pick up wood and get the carcass built up. Finish cabinetry and storage will be added later, but there will be a lot of it built in. Can't decide on walnut trimmed maple or maple trimmed cherry for the finish. I'm building one bench and I'm building it right the first time. Damn casters I want are $65 for four.

http://s142.photobucket.com/albums/r...t=IMG_2183.jpg

http://s142.photobucket.com/albums/r...t=IMG_2185.jpg

http://s142.photobucket.com/albums/r...t=IMG_2188.jpg

 

[Coreyk78]

Nice work so far, I really like all the outlets and lights. My workspace is too dark and I'm always trying to figure out what I can unplug so I can plug something else in, hehe.

 

[BoilermakerFan]

Thanks. The receptacles are all on a shared circuit with others in the finished area of the basement on a single 20A breaker, but I don't really have anything too big that needs to be plugged in at the workbench. Mainly need quantities of outlets for the 'scope, soldering station, tube tester, battery chargers, etc. The center single outlet can be easily rewired into a dedicated 20A receptacle if I need too, but it is intended to be reserved for powering whatever piece I'm testing after building. The single 20A Twist-Lock plug at the back by the panel is a dedicated receptacle so if I need big power, then I'll just go 240VAC. Lighting is all florescent so the grand total is 167 watts, but the one shop light has a pull string to take 64 watts off line when I don't need all the light. Was just down there working on the receptacle junction box and the light is nice and bright. Still need to figure out where I want to put the Ethernet, phone, cable box, but I already have a matching box and conduit ready and painted for it.

I thought this project to get the shop area done would be drudgery, but it's actually become quite fun and I keep thinking of more ideas to improve the use of space so it keeps me motivated to think it through and get it done. I'll have to start a separate thread in the off topic area once I get further along or nearly finished. I've taken lots of pics, but don't want to keep dragging other threads off topic.

 

[digger945]

Oh yea, looks great. Seems like I never can have enough light. I will be taking notes to help improve my little work area.

Like to see you at the meet in Indy this Saturday but I know it's a long drive and all.

 

[BoilermakerFan]

Thanks.

It's a long drive and the start of Spring Break for my daughter so we're heading to Cincy to visit family. Plus, while I have lots of gear in the pipeline, nothing is built and only my K601s and YH-3s are functional at the moment. Been using my vintage Yamaha receiver as my amp and it's a beast. YH-3s are going under to be modded shortly too.

A set of used ESW9s will be on their way to me shortly. I think I'm going to need to build a freestanding headphone cabinet now. Managed to build a collection with really realizing it. LOL! Have an idea for the design already and I'll be reusing some salvaged vintage privacy glass from a neighbor's old bathroom window from the late '30's. Might incorporate a spot for the Aikido, Yamaha receiver, and an Oppo CDP for a nice little office listening station.

I can't remember if I posted earlier, but my buddy has a piece of figured walnut for my front panel of my Aikido amp. Since the walnut is dark, all knobs, feet, and trim will be maple. Just waiting on John to send me the font that he uses for the manual so my text labeling will look Asian and match his manual.

 

[Coreyk78]

I think I may have some minor mental illness...

Apparently I must have had some tax return cash that really needed to be spent, because I happened to find 8 6GM8 tubes for a reasonable price and I bought them. And since my high voltage build is still being cranky, and since I just so happen to own a second 24v Aikido PCB and an appropriate power transformer I've decided to build up a 24v version and put that in my case. I've not given up on the high voltage one, but it would at least be a moral victory for me if I have a fully working Aikido with a fully proven configuration that I can actually listen to. Resistors and caps are already on order as well.

I've had some strange things happen to my Aikido since I put it into my system this week. For some reason the HP out has gone from a beatiful clean sound to a crappy distorted one while the line out still sounds perfect.

Also yesterday I had a couple of random pops in the sound from the line out that were bad enough to trip the protection relays in my speaker amp. The weirdest thing easily has to be that I can reproduce that same pop when I turn on my TV, which is on the other side of the room on a different outlet. All this has been very troubling to me and made me nervous that I'm either going to blow up my Wharfedales or my HD580s and I've been afraid to even turn on my Aikido since the TV thing happened last night.

I don't know if I have DC on my output or how to actually test for it, I didn't leave any caps off the board so I would think DC would be blocked, I don't know what the heck is going on. Oh well, I'm going to keep working on the high voltage version while I enjoy the easy paint by numbers 24v one, hehe

 

[digger945]

Quote:

Originally Posted by Coreyk78 /img/forum/go_quote.gif I think I may have some minor mental illness...

Oh good, I thought I was the only one who who had that illness

LOL!!!

 

[Coreyk78]

Quick question, my mouser order came in so I'm going to stuff my board for the 24v build tonight. I ordered 1000uF and 3300uF nichicon KW caps for C4 which is the headphone out cap. I ordered 2 sizes in case the 3300uf ones didn't fit between the heatsinks but they do. Any reason not to go ahead and use the big boys? Sonic benefits with the smaller caps at all? Just thought I'd ask since I have both.