Hey guys is it ok if i run the crack with a low impedance and sensitive headphone? cause i found out my AD2000x is quite good through the crack but im scared at the same time if it will kill any equipment.
I always try my headphones on the Crack as well. Even the low impedance ones. No harm can happen to them. However, it can sound like poop. Example: Planars - sound terrible on the Crack. However, some lower impedance headphones like the K7XX sound surprisingly good on the crack. It all depends....
But for sure the crack is not the ideal companion with anything below 150 Ohm in general.
Hey guys,
I have the HD800 and I ordered the Crack + Speedball two weeks ago, and while I'm waiting for it to be shipped, I'm starting to have some doubts about the purchase - maybe I should have gone with the Valhalla 2 instead.
What do you think?
Welcome to the crack thread roger! Happy to pick up the discussion of the pairing with the hd800's here.
With respect to the val 2 vs. crack, although both are OTL tube amps, these amps have evolved from very different design philosophies. Specifically, val 2 uses negative feedback to lower its output impedance, reduce distortion and cater to a wider range of headphones - the exact same way many discrete solid state and all opamp based amps (like your o2) do.
Bottlehead, by contrast, is committed to non-feedback topologies, which may have slightly higher overall THD and output impedance, but are free of certain complex non-linear distortions, transient intermodulation distortions and disproportionate high order distortions produced by feedback amps. Different ears prefer different things in this regard, but knowledgeable amp designers generally agree that the distortion products of non-feedback amps are much closer to the natural harmonics produced by acoustic instruments and consequently less grating to many listeners than the non-linear distortions of feedback amps. Nelson Pass, who makes both sorts of amps, has a very nice explanation of these considerations here: https://passlabs.com/articles/audio-distortion-and-feedback
Since you already have a feedback amp, I'd urge you to stay the coarse with the crack. If nothing else, building it will be a great experience and provide you with more audio understanding than the vast majority of the "unwashed masses" on HF. It is a good budget pairing with hd800's to my ears, even if it is bettered by the mainline and certain other high end amps. Ears that I trust say val 2 is also a good budget pairing for hd800's that rivals a crack, but honestly, if I were contemplating a crack alternative, I would lean towards building a torpedo (budget parafeed amp designed by Doug of ECP) before buying a val 2.
Hey guys is it ok if i run the crack with a low impedance and sensitive headphone? cause i found out my AD2000x is quite good through the crack but im scared at the same time if it will kill any equipment.
There are a couple of alternative driver tubes that can be used in the Crack that will lower the Cracks output impedance which can help sonically if running lower Z cans the Tungsol 5998 is probably the most common one. I seem to recall it roughly halves the Cracks output perhaps someone might have the correct figures saved. I ran some 42ohm ATH W1000X for a while and they sounded much better running the 5998 compared to a 6080 or 6as7g particularly the mid bass and lower regions which seem to be those most effected.
Perhaps it was one of the Tungsol/Bendix 6080 equivalents as well but honestly cannot remember what its code number was.
I'm just gonna chime in here and say that my 32 ohm Grados do awesome with the Crack. Personally I love it especially with the stock 6080 tube (for its gooey, warm, bassy sound) and an RCA clear top (to keep the treble is delicate and smooth).
Someone correct me if I'm wrong here, but for mismatched impedance, it's the bass that suffers the most, right? And in the case of the SR80i, the bass was never anything to write home about to begin with.
For drop-in replacement, I'll put in my vote for the CBS-Hytron 5814 black plate with angled getter. I like it better than the various 12AU7 variants, although I haven't tried Amperex or Mullard.
What I've noticed the most when plugging in low impedance phones with the Crack is that at a certain volume level the sound begins to distort alot. I've plugged in dt770's, HE-400's, DT 880's, and Sony MDR-7520 and they all had the same issue at louder volumes.
What I've noticed the most when plugging in low impedance phones with the Crack is that at a certain volume level the sound begins to distort alot. I've plugged in dt770's, HE-400's, DT 880's, and Sony MDR-7520 and they all had the same issue at louder volumes.
Do you have the 32 ohm versions of the dt770's and dt880's? The standard versions of these are 250 ohm, and I can confirm that my crack sounds great with 250 ohm dt880's and does not distort at high volume. Have been running this combo all day today in the office.
My experience running low ohm phones out of the crack (some audio technica's, just for giggles), was that they sounded really anemic compared to when they are properly amped, with poorly damped bass. For me, one song was totally adequate confirmation of bottlehead's disclaimer that crack was intended for high ohm phones, and I went right back to my hd650's and dt880's.
Do you have the 32 ohm versions of the dt770's and dt880's? The standard versions of these are 250 ohm, and I can confirm that my crack sounds great with 250 ohm dt880's and does not distort at high volume. Have been running this combo all day today in the office.
My experience running low ohm phones out of the crack (some audio technica's, just for giggles), was that they sounded really anemic compared to when they are properly amped, with poorly damped bass. For me, one song was totally adequate confirmation of bottlehead's disclaimer that crack was intended for high ohm phones, and I went right back to my hd650's and dt880's.
Hey guys is it ok if i run the crack with a low impedance and sensitive headphone? cause i found out my AD2000x is quite good through the crack but im scared at the same time if it will kill any equipment.
What you'll find is that after a while when the high wears off.... your low impedance headphones don't sound as clean as high impedance headphones do. A year or two may go by and then you realize perhaps a directly couple pre to output section are perhaps a bit too close for comfort.
Hey guys,
I have the HD800 and I ordered the Crack + Speedball two weeks ago, and while I'm waiting for it to be shipped, I'm starting to have some doubts about the purchase - maybe I should have gone with the Valhalla 2 instead.
What do you think?
If I switch my headphones to balanced cables for another amp, will the balanced headphones with an XLR to 1/4" cable work fine with the Crack, or is there any reason I'd need to switch back to the original SE cable when using the Crack?
If I switch my headphones to balanced cables for another amp, will the balanced headphones with an XLR to 1/4" cable work fine with the Crack, or is there any reason I'd need to switch back to the original SE cable when using the Crack?
An adapter will work just fine and is cheap and easy to make with a couple of neutrik plugs.
The typical wiring configuration for a 4 pin XLR is:
Pin 1 - L+ Pin 2 - L-
Pin 3 - R+
Pin 4 - R-
So at the other end, pin 2 and 4 should be connected to the sleeve (signal ground) of the TRS, pin 1 the tip (left channel), and pin 3 the ring (right channel).
Bottlehead, by contrast, is committed to non-feedback topologies, which may have slightly higher overall THD and output impedance, but are free of certain complex non-linear distortions, transient intermodulation distortions and disproportionate high order distortions produced by feedback amps. Different ears prefer different things in this regard, but knowledgeable amp designers generally agree that the distortion products of non-feedback amps are much closer to the natural harmonics produced by acoustic instruments and consequently less grating to many listeners than the non-linear distortions of feedback amps. Nelson Pass, who makes both sorts of amps, has a very nice explanation of these considerations here: https://passlabs.com/articles/audio-distortion-and-feedback
Since you already have a feedback amp, I'd urge you to stay the coarse with the crack. If nothing else, building it will be a great experience and provide you with more audio understanding than the vast majority of the "unwashed masses" on HF. It is a good budget pairing with hd800's to my ears, even if it is bettered by the mainline and certain other high end amps. Ears that I trust say val 2 is also a good budget pairing for hd800's that rivals a crack, but honestly, if I were contemplating a crack alternative, I would lean towards building a torpedo (budget parafeed amp designed by Doug of ECP) before buying a val 2.
Excellent post and the linked article by Pass is a great read. The Crack w/Speedball and the ECP/Beezar Torpedo are the best value tube headphone amplifiers I've personally heard. I personally like my Crack better with higher impedance cans like my DT990 600ohm and modified Darth Beyers, but that's with copious tweaking and part changes. As stated, the Edcor output xformers make the Torpedo a better candidate for Grados, Denons, etc. Also don't forget about the S.E.X., output transformers and adjustable impedance switching, that's a great jack-of-all trades amp with a slightly lush sound. I love mine.
Excellent post and the linked article by Pass is a great read. The Crack w/Speedball and the ECP/Beezar Torpedo are the best value tube headphone amplifiers I've personally heard. I personally like my Crack better with higher impedance cans like my DT990 600ohm and modified Darth Beyers, but that's with copious tweaking and part changes. As stated, the Edcor output xformers make the Torpedo a better candidate for Grados, Denons, etc. Also don't forget about the S.E.X., output transformers and adjustable impedance switching, that's a great jack-of-all trades amp with a slightly lush sound. I love mine.
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