[Misterrogers]

I installed a pair of E90CC's bought from Tom about a month ago. At the same time, I changed diodes and added snubbers. I have about 100 hours of playing time with these tubes, and have to day that they've really elevated the Torpedo up a notch. My currently used home/work chains are identical except for a Torpedo at work and a Crack at home. While the Crack slightly edges the Torpedo with E90CC's in sound stage and dynamics, the detail/texture of the Torpedo has me missing it when I'm home. Almost brought it home with me for the holiday break
 
For reference, my Crack has Speedball, upgraded caps, and upgraded attenuator.

 

[tomb]

  I installed a pair of E90CC's bought from Tom about a month ago. At the same time, I changed diodes and added snubbers. I have about 100 hours of playing time with these tubes, and have to day that they've really elevated the Torpedo up a notch. My currently used home/work chains are identical except for a Torpedo at work and a Crack at home. While the Crack slightly edges the Torpedo with E90CC's in sound stage and dynamics, the detail/texture of the Torpedo has me missing it when I'm home. Almost brought it home with me for the holiday break
 
For reference, my Crack has Speedball, upgraded caps, and upgraded attenuator.

 
 
Thanks for the comments! 

 

[Punnisher]

Had another audio meet with my friend Tim, and the Torpedo was the focal point. We are both blown away by the sound coming out of the Telefunken E90CC. The midrange and treble are incredibly resolving. Instrument and vocal placement is spot-on. For me, center-mixed vocals are close and intimate and instruments often feel like they're in the room. It also does extraordinarily well with instrument layering and fast textures.
 
My personal favorite pairing is currently the k601 w/ k702 pads. FYI, I am not affiliated with Beezar in any way, but rather a very excited listener.
 
Tim took quite a few pictures. Here's a selection:
 

 

 

 

 

 

 

 

[tomb]

Wow!

 

[tomb]

I added a web page for the 5920/E90CC tubes on the Torpedo website.  It has some good links and all the data sheets I could find on the E90CC.  There's also a bit of information for the E92CC - a similar tube - but it's more like a very-detailed 6J6, not really completely up to the level of the E90CC.  Still, if you can find them, they may be worth a shot.
 
Everyone who owns a Torpedo should have a pair of the E90CC's, IMHO.

 

[Punnisher]

Thanks for the heads-up. I'll check out that one too.
 
I was searching a while back and found the radiomuseum.org page for the E90CC: http://www.radiomuseum.org/tubes/tube_e90cc.html
 
It gives some info in regards to equivalents and similar tubes.
 

Identical to	E90CC = CV5214 = 5920
Similar Tubes	Normally replaceable-slightly different:  ECC960

 
Do you have any info on the ECC960 or CV5214?

 

[tomb]

  Thanks for the heads-up. I'll check out that one too.
 
I was searching a while back and found the radiomuseum.org page for the E90CC: http://www.radiomuseum.org/tubes/tube_e90cc.html
 
It gives some info in regards to equivalents and similar tubes.
 

Identical to	E90CC = CV5214 = 5920
Similar Tubes	Normally replaceable-slightly different:  ECC960

 
Do you have any info on the ECC960 or CV5214?

This is what's on ebay right now:
http://www.ebay.com/sch/i.html?_trksid=p3984.m570.l1313.TR0.TRC0.Xecc960+tube&_nkw=ecc960+tube&_sacat=0&_from=R40
 
It appears to me that the ECC960/CV5214 is a total equivalent to the E90CC, sort of like 6J6 vs 6J6A or 6J6W.  (Maybe it's a Russian/former Eastern Bloc version of the E90CC?)*  That's not all bad, though, because it gives another potential source for tube stock and options.
 
The thing that made the 5920/E90CC such a discovery is that it and the rest of the tubes above were not listed as a functional equivalent to the 6J6 - anywhere.
 
* Except for two Russian links, my TDSL Personal Edition lists 5920 and E90CC datasheets for the ECC960.

 

[FishHead]

They are coupling caps, but there is an argument that their inductance interacts with the inductance of the OPT in a way that is different from what would normally happen with a coupling cap. But, if caps make a difference, then his would seem to be a place that they would. I used V-Caps in the L-2 after liking them better than a bunch of others I tried (Mundorfs, etc.) and I definitely thought I could hear a difference.

I am visualizing my build and can only find V-Caps rated at 250V@4.7. Is there something I am missing?

The other cap candidates are mundorf supremes, obbligato prem gold, and modWright.

My chain will be Galaxy S3> Fiio E18> torpedo> k701 or s3> torpedo> k701 depending on how the DAC sounds. All recordings are FLAC. Thanks for any help!

 

[tomb]

 

They are coupling caps, but there is an argument that their inductance interacts with the inductance of the OPT in a way that is different from what would normally happen with a coupling cap. But, if caps make a difference, then his would seem to be a place that they would. I used V-Caps in the L-2 after liking them better than a bunch of others I tried (Mundorfs, etc.) and I definitely thought I could hear a difference.

I am visualizing my build and can only find V-Caps rated at 250V@4.7. Is there something I am missing?

The other cap candidates are mundorf supremes, obbligato prem gold, and modWright.

My chain will be Galaxy S3> Fiio E18> torpedo> k701 or s3> torpedo> k701 depending on how the DAC sounds. All recordings are FLAC. Thanks for any help!

Dsavitsk mentioned his excellent L-2 in that post.  That's a different amp and 250V may have been fine.  The Torpedo needs 300V rated caps at a minimum.  B+ has been measured at over 250V by several builders (I'm too chicken to measure it myself).  There are many others available besides the ones you listed, however.  You can even use a Wima box film cap on the Torpedo, available through Mouser.  Mouser also has a Cornell-Dublier axial film cap that Kevin Gilmore said was a very good capacitor.  Mundorf has many models that will work at all types of prices.  Dsavitsk used an Auricap in his Torpedo prototype.  Many of the early prototypers also used the Mundorf M-Cap MKP - there's one rated for 400V that's only $6.65 from PartsConnexion.  Besides the 4.7uf and 300V minimum rating, just pay special attention to the dimensions and lead spacing available on the Torpedo PCB and you should be fine. 

 

[FishHead]

Thanks tomb.

 

[tdubl07]

Hey guys, I just got done building my torpedo and have a few questions. Up until now I've owned nothing but OTL amps. I'm trying out my he-400's right now, (with the telefunken e90's being fed from my modi dac) and this doesn't seem to be working out well. The bass is lacking a great deal compared to my mini max, project ember, and even my starving student build. Is this just how full tube amps are? Also my he-400' start to distort at higher volumes as if there's not enough oomph to drive them (I'm at about 3 oclock on the pot). Something seems off to me with the sound I'm getting. I've went back over any solder joints that looked even remotely suspicious and all look very good. It's dead quiet however, no noise at all which is great, no hums of any sort. Measuring 272VDC at B+. You guys think this amp will pair better with my 990 pro's at work? I'm hoping so and will try out tomorrow. This also has the snubber caps and choke as supplied by Tomb since I just got my kit in. What do you guys say?
Thanks

 

[Punnisher]

I tried a pair of HE400 with my Torpedo (Telefunken E90CC) and it wasn't a good match in my opinion. It was very warm, lush and didn't seem to extend much into the treble frequencies. This is odd, because every dynamic headphone I try with my amp is hyper-detailed and a bit analytical (the way I like it).
 
Take it with a grain of salt because the HE400 was defoamed. It sounded neutral with other types of amps, including the SS hybrid.

 

[tdubl07]

  I tried a pair of HE400 with my Torpedo (Telefunken E90CC) and it wasn't a good match in my opinion. It was very warm, lush and didn't seem to extend much into the treble frequencies. This is odd, because every dynamic headphone I try with my amp is hyper-detailed and a bit analytical (the way I like it).
 
Take it with a grain of salt because the HE400 was defoamed. It sounded neutral with other types of amps, including the SS hybrid.

Thanks Punnisher. Does the amp seem like it's powerful enough with everything else? I tried some AD-700's which are insanely easy to drive and still need at least 12 o'clock on the pot to get decent volume. I guess I may have been assuming more power from this build. Just curious. Thoroughly enjoyed the build, I'll wait for my full judgement until tomorrow with my 990's at work.

 

[Punnisher]

The amp has enough power with every dynamic I've ever tried with them. In fact, I'd have to say it's the best amp I've ever heard for any dynamic, ever. I've tried a lot of expensive amps. Keep in mind I'm using the Telefunken E90CC.
 
You have to take into account the voltage of the input signal, the volume with which you listen, the average volume of the music, and the gain setting of the amp.
 
I listen at low-medium volume compared to most people. My source is putting out 1.5-2vrms. With the headphones and music I've tried, I usually have the dial around 10-2 o'clock. Maybe lower if the headphones are really efficient. With the HE400 it was 3:00 or more!
 
I have heard that the amp was designed with a "safe" gain setting that should work with most setups. Perhaps it could be modified to offer some more gain.

 

[tomb]

Yes, Dsavitsk will have to weigh in about gain.
 
Punnisher is correct when it comes to the standard gain on the Torpedo and the position of the volume pot.  Almost every dynamic works out to about 12 o'clock.  That's one of the beauties of the amp - doesn't matter whether Grado at 32 ohm or Sennheiser HD 580/600/650 at 300 ohms - flip the Z switch and everything is adjusted at 12 o'clock for reasonable listening volume.  The only exception to this that I've found with dynamics is the K701 family - more like 1-2 o'clock for the same volume.
 
You might try the 6J6 tubes - especially the 6J6W's that I supplied.  Those are among the nicest of the 6J6 family.  The amp definitely sounds better with the E90CC's, but nevertheless, the amp is optimized for the 6J6's.  It's true that the output transformers are going to do all of the converting to voltage and current at the output, so tube selection is not going to affect power that much.  However, the 6J6's may have a bit more punch with the amp (but not the exquisite detail/low distortion of the E90CC's).  Depending on the headphone, that may be a better fit, I don't know.
 
Max power was estimated by Dsavitsk at about 750mW, I believe.  I would be surprised if some OTL amps exceed that with low-impedance loads, but I suppose if the tubes were very powerful in their own right, it might.