ECP Torpedo III [indexed in first post]

Good work mates!

It's tedious to fit them in, but as Tom said - well worth it!

 

Well fudge - not enough time left in the day - still working on the web page for the Mundorfs.

 

http://diyforums.org/Torpedo-III/TorpedoIII-tweaks3.php

Let me know if you guys see some mistakes. I think this pretty much covers the Mundorfs, though.

 

Nice write up TomB. I wonder if a potential future iteration of the T3 might have a more cap-friendly form factor.

 

Excellent write up Tom!

 

Such things have of course been talked about. For the T3 we wanted to maintain the form factor as it allowed us to reuse parts and save a lot of money (a savings we pass on to the consumer). The downside is that doing so provided a limited space for coupling caps as neither the tubes nor transformers could move.

I find using extremely expensive caps to be the wrong direction as it is possible to eliminate the caps altogether. However, that requires a more elaborate circuit, and a more expensive OPT. And that makes it into an ecp amp, and not a DIY one.

 

As much fun as it has been building this amp, is there an ecp amp that is a better version of the Torpedo? I'm not sure I'd switch, but it'd be interesting to know.

 

Haha yeah, I also read into the innuendo in Doug's message, or maybe it was just wishful thinking. I'm really happy with the T3, but maybe down the line a ECP enhanced Torpedo would be interesting!

 

ECP L-2, I believe, no?

 

The L-2 is similar to the T1.

There are a couple of things in the works that are similar-ish to the T3. I am hoping to have at least one of them in Atlanta, and several new things available this summer.

 

Working on the T3 it looks like the first step is the hardest or most scary step? Those smd transitors is scary to soldier I don't want to accidently fry them.

 

Shiit I think I lost one the little smd it fell in the carpet fml.

 

Its optional, happened to me too.

 

They're capacitors and work to cut down oscillation in the rectifiers that could be picked up by the power transformer and transmitted as noise through the rest of the amp. We had a particularly troubling issue with the Torpedo 1 that we thought was ripple early on. Turns out, the rectifiers were oscillating and the PT was picking it up. The noise was audible and sounded like a high hum. Use of slightly different rectifiers and mainly - the capacitors as power supply "snubbers" - was the solution.

I'm not saying that the T3 acts that way without them, but if you want to ensure that the amp has the lowest power supply noise possible, you should install them.

As for SMD, those two capacitors should be the easiest parts to install in the whole amp. You need good SMD tweezers, but once you have those, it's a snap. Apply solder to a pad. Grab the SMD part with the tweezers in you non-soldering hand. While melting the solder you just applied on the pad, move the edge of the SMD part into the solder. While still holding it in position and flush with the PCB, remove the soldering iron and let the solder cool to solid (a second or less). Now go back and apply solder to the other pad/other end of the SMD part.*

Except for bouncing the part into the carpet like a flea or tiddly-winks, it's easier than through-hole soldering.

Shoot me a PM if you've really lost it and I'll send you some more.


* Look on diyforums.org for any of the little DACs that Beezar Audio sells. There are extensive instructions on how to solder SMD.

 

Just a quick note to remind everyone messing with the Mundorfs:

There is NO polarity on film caps. There may be some exceptions out there - Auricap likes to make a distinction - but this is rare. The Mundorfs are not in that category.

 

Just finished my Torpedo III build today and it's an amazing amplifier! Compared it to my crack and it's no contest. Torpedo III has better sound stage I usually use surround field effects on JRiver, but now with Torpedo III I don't even need it on. The T3 has better dynamics and micro details, it's not as warm as the crack, it's more neutral, it has more upper treble because the crack rolls off the treble more. It sounds very good with my HD650.

 

Just wanted to chime in here. Received my TIII from TomB last week and have been spending some quality time with it whenever I can. Coming from a Gilmore Lite, the change with my HD800 isn't subtle. The sound was on the lean side, particularly compared to my AD2000s with the same amp, but the TIII has made the HD800s quite a bit more engaging. At least for the time being, I'm going to sit back and enjoy the combination...

 

I think the T3 in your case is just showing you what the AD2K is at its core. FWIW you may try an OTL amp like the Valhalla 2 or something for the ad2k specifically to add some meat back to the bones.

 

Completed my T3 and just got it fired up this morning for the first time. My mundorf install looks super sloppy but works. It has the Cinemags and Mundorf Al-Oil, and being driven off the Gungnir MB.

I think I may have a cold joint somewhere in the right channel, but I only notice it with Grado's. Like a intermittent crunchy static noise in the right channel. Don't notice it with the HD-650 though. Could just be the wire on the Grado getting too twisted also.

Soundwise, I'm very satisfied. From the Valhalla 2, there is a noticeable improvement improvement in bass depth and quality. Lending to a better sense of "PRaT". Much more " toe tapping" or "Head bobbing" with the right music.

There is also a better sense of solidity in comparison, likely due to the hybrid topology. You get some of that solid state definition, without losing the dimensionality of the tubes.

To mirror some others here, it pairs very well with the HD-650. I really wish I still had the HD-800 to compare. I think it would do well too. The Valhalla 2 also drives the HD-650 well, but the T3 seems to inject a little more life and drive into them by comparison. No regrets so far though. Can't wait until I get the purpleheart TH-X00 in August though, to try with it.

 

I'm using that exact combo with hd800 and it's what I listen to the most. Just awesome. Tubes are amperex 7062.