Case for Helder's TA2020 MKIII Amp Module

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Are either of you guys going with the tube buffer at any point? I will probably wait until after I get acquainted or bored with the ta2020 amp before I make a decision on that, but it sure looks good, and supposedly makes the amp "smoother" sounding.

Hi,

I have the buffer feeding his TK2050 boards. Excellent stuff. Classic rich tube sound with solid bass. The input caps are ok-ok quality and the tube is made in China but I was impressed with the sound. You could tube roll any of the
12AU7 series.

I don't even have a case. The boards are on the floor LoL. If I were to build them up, I'd build separate enclosures for the modules and powersupply. I am using the Meanwell 24V SMPS @ 6A. Extremely quiet. The voltage can be adjusted from 21-28V so if you build it in a separate enclosure, you could power any future amplifiers that require that voltage.

Sorry whaleman I don't have that wiring diagram.
Some listening impressions...one of the best value for $$. Sound is smooth, tube like, wide soundstage and warm bass. Highs seem a touch too soft though. Detail/imaging is not as good as my Aussie Amplifier Nxv200. Overall I cannot say it is audiophile grade sound, but it is amazing value. Just my 2 cents.
 
Here is an explanation of the selector switch quoted from Arjen:
The center of the switch has 4 pins in the middle, you can use 3 of them, one for GND of both channels, and 2 for L & R these wires go to the amplifier.



Then if you look from the side in to the switch you can see a moving contact that can slide over 3 pins. If you look further you can see that the switch is divided in 4 parts, every quarter of the circle represents the middle pin, so you can solder the inputs for 3 left channels to one quarter, 3 inputs for right to the second quarter and 3 GND’s to the third quarter. The 4th quarter is not needed.

Hope that helps.
 
The MKIII is done, almost! Maybe some labeling and some matching knobs will finish things off, but for now I am quite satisfied with the outcome. The sound is great and having the built-in power supply makes a huge difference. Quite worth the effort.

The selector switch that came with the kit gave problems right away, so I had to scrap one from a Pioneer SX-580. I installed an additional Nichicon power supply capacitor brings the power reserve to plus 18,000 uF.

The power transformer is a Hammond 40 volt-amp (10 VAC 4 amps). I installed X and Y class capacitors to quiet the AC line RF noise. Set the DC offset to 0 with the trimpots. So far so good.

Notice the UFO probe outside the window trying to steal the technology already, I guess they don't have the internet.
 

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Seeing all the great work in this thread has inspired me to finish my MKIII board (and my first audio DIY ever!)

The case I used is a Hammond 1455T, and my inexperience is probably evident by the poor soldering and wiring quality. I still need to get inside and properly clean everything up, but overall I'm proud of my first project.

Great work everyone, and thanks for the inspiration. :)
 

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Hi kickngas, thanks for the comments! I am very impressed with how clean your internal layout and wiring is, and I wish I had a chance to see how it's supposed to be done before I finished up my soldering. ;)

I placed the 2 LEDs behind the volume knob (above and below), but I had to use 3mm LEDs (expensive!), since 5mm LEDs were too big and wouldn't fit nicely between the knob and the potentiometer; even with 3mm LEDs, the fit in there is tight, and I even initially had a grounding-out problem because I tightened the pot too tightly and it rubbed through the LED insulation. My next project may substitute SMD LEDs mounted right on the aluminum if I decide to go that route again.

I also found that I needed to wire the LEDs into the 12V rail with 150ohms of resistance for brightness, as the MKIII's PWR indicator seems to send very low current and couldn't drive any LEDs with enough brightness to get the effect I wanted. As a result, the front LEDs only indicate PSU power, and I relocated the board's indicators to the less practical position in the back, next to the power switch.

One downside of my implementation is that the LEDs are visible and cast off a lot of light if you look at the unit from the side or the wrong angle; this could be lessened if I trimmed down the pot and brought the knob a little closer to the case, or if I even put a little bit of paint on the sides of the LED so that less light would spill out the side.

In all honesty, if I had seen what you had done for the LED and realized how clean it would have looked, I would have gone the way you did; the end result came out about as nice as I had expected, but the swearing and aggravation almost made me abandon the idea altogether! :D
 
Glad to see you all's MKIII, very very nice and well done. Kickngas you are an artist with the shrink tubing and Bokchoi very modern, clean, and not novice work at all.

I did some cleaning up to mine today since I had some AC bleed and dissimilar signal to both channels. I had a spare Alps pot that was better quality and shifted the signal wiring away from the AC supply and lines. Matching knobs are now installed.

Would love to hear your impressions on dynamics since you both used the switching power supply.

The supplemental 12,000 uF power capacitor seems to make a big difference in reserve power as the unit plays a good after power off. It was a snap installation since I had the DC power supply line to spare with the unit being AC powered and on-board rectified.

The Clipping LED is handy because the unit clips before you can hear it and if your get too happy with the volume coupled with inefficient speakers. Not a problem with the speakers you see in the picture and they are about 100 dB efficient. However, with my Fried speakers, they can make the amp clip.

I find the unit has a very nice mid section, highs are clean, bass is OK. Unusually clean and detailed sound.

Thanks for sharing your pics, keep them coming.
 

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I'm not really one to comment on dynamics as I'm still quite new to the audio world; my last amp was a Lepai LP-2020 to which I did all kinds of terrible modifications, but didn't really understand the operation of.

The switching PSU I used is a 12v 3.5A, purchased from Arjen along with the MKIII board; I think Kickngas used a 12v 5A model which may be available from Arjen as well. Looking back, I'm happy I chose the smaller size as I was able to find a housing that could fit it neatly. I was originally a bit concerned that placing the PSU inside the same housing as the board could cause undesirable effects, but seeing your implementations have helped me lay those fears to rest.

In my estimation and after a few hours of listening, I would say my version of the MKIII does sound better than the LP-2020 after modification, but how I can't say exactly how; I suppose I would say the clarity has been the biggest improvement, but I'm otherwise really not experienced enough to describe it. I suspect I will be able to better describe the sound quality after a few more days and after the unit has had a little bit of break-in time, if this board lends itself to that kind of change.

Thanks again for your compliments; I still have much to learn, but I am already looking forward to many new audio DIY projects in the future.
 
OK, we all had some time to listen by now. I am totally impressed with what Arjen's TA2020 can do.
Bass is very good with my large 16 ohm speakers. Mids are clean, highs shine nicely, though on lesser recordings there is a bit of sizzle at the top end. Imaging and speed are incredible. Placement of instruments is very precise. Three dimmensional echoes are most fascinating. There are room echoes on stuff that I never heard before and were probably not heard by the recording engineers, neat stuff. It is a great reference amp since nothing gets past it. Only weakness I find is mid-tone slam, but this is probably due to the low wattage output and the large size of my speakers. Can't wait to build the next one with a tube buffer in the front.

Now let's hear your impressions of the Helder TA2020.
 
Here is the third MKIII finished today. Not broken in but sounds very good. That big Sangamo cap was just sitting around, so I threw it in since I had the room because the tube buffer was too tall.

So now I have a new tube buffer to spare, if interested PM me, will ship out of the USA.
 

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