[Misterrogers]

It is one fantastic little amp. I didn't get a chance to run mine with HD800's, but it drove anything high impedance wonderfully, and handle many low impedance cans capably. This little guy made me a big fan of 'Parafeeds'.

 

[OJNeg]

Yessir. I'm sold on the Parafeed topology as well. If only I could get my hands on a ECP L2...Or maybe a BH Mainline is in the future for me!
 
I've had some fun rolling tubes with the Torpedo though. The Torpedo seems to respond well to switching out the critical components (tubes and caps). Right now I'm stuck between the E90CC (amperex) and E92CC (philips miniwatt). Both have different signatures but it's hard to say which is "technically" more capable so to speak. I keep both out of their boxes and switch 'em depending on my mood.

 

[Punnisher]

I agree. The Torpedo works wonderfully with the HD800. I auditioned it a while back and was very pleased.

 

[Daveze]

Local electronic parts store (Jaycar) didn't have any 125mA, so bought 100mA (too small) and 160mA (...not too small) fuses.
 
My goodness this is an amazing amp. Currently running the 6J6 through a pair of AKG K240M, hearing things that I've previously never heard (Millet MiniMAX). Looking forward to rolling in the pair of E90CC and maybe then maybe some Jantzen Crosscaps...

 

[OJNeg]

  Local electronic parts store (Jaycar) didn't have any 125mA, so bought 100mA (too small) and 160mA (...not too small) fuses.
 
My goodness this is an amazing amp. Currently running the 6J6 through a pair of AKG K240M, hearing things that I've previously never heard (Millet MiniMAX). Looking forward to rolling in the pair of E90CC and maybe then maybe some Jantzen Crosscaps...

 
I tried the Crosscaps in my Torpedo before moving on to the Z-Silvers. Let me know if you want them and I'll throw 'em in an envelope for you.

 

[Daveze]

How did you find the difference between the Crosscaps and Z-Silvers? What about the fit, aren't they a few mm long?
 
I'll gladly take them...PM incoming.

 

[dpump]

See Post#535 for pictures of my Torpedo with ClarityCap MR 400V capacitors. The largest dimension on the PCB for the coupling caps is 51.75mm. The MR's are 50 mm. I guess you can fit caps longer than 50mm by bending the leads under the cap and then bending them down as there is some height to play with. I have done this on other amps. I originally had ClarityCap SA's in my Torpedo. The SA's were smooth and somewhat warm, but lacking in the amount of high end I like. After reading cap reviews, I decided to go with the MR's and I have been very pleased with them. I hear more overall detail and more high end. Didn't seem like they took long to settle in-they were a little rough at first but seemed pretty good after 5-6 hours.
 
I have used Jantzen Superior Z caps in a couple of other amps. They are very smooth and detailed without harshness. Haven't tried the Jantzen Silver Z caps. I might have used the Superior Z instead of the MR if the Superior wasn't  56mm long. Didn't want to deal with the extra length and prefer a neater installation. I'm sure the the Jantzen Crosscaps are good, but I would personally recommend something better, as the Torpedo will easily show the improvement a better cap will bring. Maybe try the ClarityCap above the SA, the ESA.

 

[OJNeg]

Yes, I have to bend the leads under the ends to make it work for the Jantzen Silvers. A minor inconvenience. I have a bit of plastic under the caps to keep stress off the leads otherwise they wouldn't be flush with the PCB.
 
I do agree that the Torpedo warrants better caps than the Crosscaps, but it depends on how far you're willing to dive in.

 

[JamieMcC]

Hi guys has anyone recorded running voltage readings for C11&C12 the Parra-feed signal caps? I am wondering what the normal working voltage is and the peak voltage the caps see and for how long that may be for.
I have some caps that are rated at 310V for working load but they do have a peak rating of 500V for 30days before failing. So wondering if they might be usable if they are not to far out of spec. I note 400V quoted?
 
Thanks
Jamie

 

[OJNeg]

  Hi guys has anyone recorded running voltage readings for C11&C12 the Parra-feed signal caps? I am wondering what the normal working voltage is and the peak voltage the caps see and for how long that may be for.
I have some caps that are rated at 310V for working load but they do have a peak rating of 500V for 30days before failing. So wondering if they might be usable if they are not to far out of spec. I note 400V quoted?
 
Thanks
Jamie

Good question. On turn-on there's no current running through the tube so the anode (that's where the parafeed cap is coupled to) gets pulled high to B+ (~260V). It stays that way for 10-20 seconds. After the heater warms up and starts glowing the anode will drop down to its working value. It'll depend on the tube actually. I've measured 150V for the 6J6 and 90V for the E90CC.
 
If your caps are rated for a 500V "peak" then you should be fine. Obviously the working load is much lower than that rating too. Out of curiosity, which caps are you planning on throwing in there?

 

[JamieMcC]

 
Good question. On turn-on there's no current running through the tube so the anode (that's where the parafeed cap is coupled to) gets pulled high to B+ (~260V). It stays that way for 10-20 seconds. After the heater warms up and starts glowing the anode will drop down to its working value. It'll depend on the tube actually. I've measured 150V for the 6J6 and 90V for the E90CC.
 
If your caps are rated for a 500V "peak" then you should be fine. Obviously the working load is much lower than that rating too. Out of curiosity, which caps are you planning on throwing in there?

 
Thanks that's great info, the caps I hoped to try are 10uf RTI Teflon & Tin foil 310V DC originally from a batch manufactured for Audio Research (I think Misterrogers a few post above used some in his Mainline build)? 
 
The Torpedo has been tempting me for about 18 months, but only dipped my toe into diying a year ago with a Crack build.
 
cheers

 

[OJNeg]

Torpedo vs Crack is an interesting comparison. See what you think.

 

[dpump]

   
Thanks that's great info, the caps I hoped to try are 10uf RTI Teflon & Tin foil 310V DC originally from a batch manufactured for Audio Research (I think Misterrogers a few post above used some in his Mainline build)? 
 
The Torpedo has been tempting me for about 18 months, but only dipped my toe into diying a year ago with a Crack build.
 
cheers

The caps in the Torpedo are spec'd at 4.7uF, so I don't think you can use 10uF. The designer would have to verify this to be sure.

 

[dsavitsk]

10uF is fine. However, I find it difficult to believe that there are 10uF 310V Teflon and foil caps that will fit the board. 0.1uF certainly. 1uF, possibly. 10uF seems unlikely. It also seems unlikely that they would be available and not cost more than the rest of the kit.

 

[JamieMcC]

I to am unsure if the Teflons will actually fit having just measured one they are 56mm long x 49mm dia. Originally from a batch of 40 (I believe) custom ordered to go in one of Audio Research's reference tube preamps. A mix up in the order resulted in the right uf value but wrong physical size the batch was disposed of via TC tubes who are located close by at substantially below cost. Initially listed as a once in lifetime opportunity at around $80 each but as the stock reduced the price crept up to $120 each. From what I have found on the net RTI are supposedly the main oem manufacture for the US Teflon capacitor market suppling several of the premium makes.
 
Quiet a few where snapped up by Bottlehead builders as the caps are a perfect substitute for the parrafeed caps in the Mainline. I brought a couple as I thought of them as a investment to keep and try in future projects over the years ahead.
 
Edit
 
This the pic I found whist researching on the net that made me wonder, looking at some pics of different caps installed it looks like there might possibly be enough wriggle room either side of the widest spaced terminal holes.