[jdkJake]

Quote:

A question, though, how the heck did you get a Guvment Employee Postal Worker to deliver a package to you today?

 
 

Surprised me as well. I heard the mail truck pull up and there it was, on the front porch. No other mail though. 
 
Made my day.  

 

[jdkJake]

Quote:

There is an "unofficial" schematic at http://www.ecpaudio.com/Torpedo.shtml with parts labeled. I'll get a power supply up later, and Tom should have the website up soon.
-d

Great. Thanks.

 

[HiGHFLYiN9]

Got my order in over the holidays. Thanks again gents for all the hard work you put into this. 

 

[jdkJake]

Rainy day in Florida as the cold front comes in. Good day to build an amp.
 
TomB/dsavitsk,
 
I assume this jumper also needs to be installed to connect the tube heater filaments to the power supply?
 
 

 
Just checking to be sure as the build pics and text on page 1 does not mention it.
 
 

 

[dsavitsk]

Nope, no jumper.

Temporary power supply schematic up at http://www.ecpaudio.com/Torpedo.shtml

 

[jdkJake]

Quote:

Nope, no jumper.
Temporary power supply schematic up at http://www.ecpaudio.com/Torpedo.shtml

Ah, just a couple of vias to the top to jump a couple of bottom traces. Got it.
 
Thanks again for the temp schematics.

 

[Gabe Logan]

Mine just came in. The care in packaging everything was great. Thanks tomb and dsavitsk.

 

[jdkJake]

"Burnin' and Lootin' tonight!..."
 
Another Torpedo lives and we be jammin'.
 

 
The build itself went fine. Extremely straightforward. The schematics were nice to help understand the parts and their roll in the circuit, but, you could easily build this from the BOM and the photo strip TomB posted on page 1 and 2. The main issue, as TomB has pointed out is the awkwardness of the board once you get the transformers installed. Talk about a moment arm! Nothing insurmountable mind you, just something to be aware of. 
 
I went with the choke and a pair of Mundorf MCap MKP's I tagged onto a Parts Connexion order during one of their 20% sales (~$4.76USD a piece).
 

 
So, far, while still very, very early, I am liking what I am hearing. Even out of the iPod line out using 192k AAC rips, the 225's sound mighty tasty. I have been running it for a couple of hours now. B+ started at ~229VDC and is down to about ~224 at this point. The tubes were NOT matched, so, the plate loads vary considerably at this point (PL is ~133VDC and PR is ~157VDC). I suspect one could get this much closer with a little effort. Perhaps later in the week once everything is boxed up and a bit more stable.
 
The case is still in paint, but, should be ready sometime tomorrow. I will feel a bit better moving it around it once it is boxed up. I am dying to hear what is sounds like on the main rig with the HF-2's.
 
Much thanks to dsavitsk and TomB for putting in the hard hours and making this build possible. It is quite the accomplishment.
 
A toast to the Torpedo, dsavitsk and TomB with the appropriate (and equally tasty) libation. 

 

[ujamerstand]

How do you like it to your EHHA rev.A?

 

[jdkJake]

Quote:

How do you like it to your EHHA rev.A?

Too early to tell.

 

[ujamerstand]

Please do let us us know! 

 

[tomb]

Quote:

"Burnin' and Lootin' tonight!..."
 
Another Torpedo lives and we be jammin'.
 

<snip>
A toast to the Torpedo, dsavitsk and TomB with the appropriate (and equally tasty) libation. 

Yes - one of my favorite libations, too.  Purely a coincidence, of course.

 
 

 

[jdkJake]

TomB,
 
Another quick BOM correction. Part D9 (1N4448) is specified as quantity two, should be quantity 1.
 
There, I just shaved $0.13USD off the BOM. Whoo Hoo!!  

 

[jdkJake]

I realize the PL/PR measurements don't necessarily reflect tube mu/gm matching characteristics, so, I decide to take a quick, crude measure to see how close this set of tubes I was using matched in output. At the end of the evening, the PL and PR measurements between the set of tubes I was using had a difference of ~30VDC (~130/160VDC respectively). This actually turned out to reflect about ~2db in channel imbalance for this particular set of tubes (zero attenuation on the Alps/high impedance setting). While not offensively off, it was slightly noticeable.  
 
I went through a couple of the other tubes I have of the same construction and now have a set that measures ~158/~162VDC respectively. This turns out to be less than ~1db of channel imbalance (zero attenuation on the Alps/high impedance setting). I think this is pretty darn good for tubes especially taking into account the channel tracking/imbalance error margin inherent in the RK27 itself. I am going to leave this set in for a while and listen with it for a while.
 
BTW, my case is still in paint. Needed another coat in a couple areas (mainly on the clam shell connection). So, casework is put off yet another day. 

 

[vvs_75]

Got a question about Q5,Q6 and VR1.
 
From post #9:
"Torque is probably too strong a word, though, because you want to tighten them so that the lock washer is obviously compressed, but not enough so that the thermal pads get cut.  There is high-voltage going through the CCS transistors, so you don't want them shorting to the heat sink."
 
 
The MJE350 and NJM2396F63 looks like they isolated,  in which case thermal pad  or paste  requires only for better heat transfer not isolation from heat sink.  Just want to be sure. Thanks