Bottlehead Forum
Bottlehead Kits => Legacy Kit Products => Quickie => Topic started by: denti alligator on February 15, 2014, 04:41:11 PM
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Not to derail the thread, but what would be a good match for the converted Quickie?
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Well, biblically Mary Magdalene was said to have found Jesus a good match. But Bottlehead has very little expertise to offer on the subject of saving wayward ladies.
Oh wait, you mean a headphone that would match the Quickie-plus-Speco? Anything that meets both of the following two criteria:
1) Sensitivity greater than 105dB/mW. There are very, very few.
2) Matches the impedance of the available taps, which depends on which output transformer you are using. I've posted on those fairly recently.
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Hah, nice one!
Can you point me to where you've posted on impedance ...
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Following up on this:
what is the impedance if I'm using the SEX 2.0 transformers*?
Also, what is 105dB/mW in SPL?
*mine are wrapped in gold-brown not yellow. are these the right ones (the old, not the new)?
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Bummer. Though those transformers are fairly cheap ($6 on ebay), so I may get some and try this mod.
I'm having difficulty figuring out what 'phones to pair it with. Can anyone help there?
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Try Grados.
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Almost all the Grados have sensitivity of 99.8db, which would be too low, or?
Looks like Sennheiser HD598 is 112db sensitivity...
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The SEX 2.0 transformers are not Speco transformers, and do not have the appropriate taps for this modification.
-PB
A follow up on this. The transformers have T7010 on them. These aren't the Specos?
And if not, Paul Joppa suggested in the other thread that they might work:
You mean, I think, the oldest ones from before the Specos. Your transformers are very similar to the Speco, and should work about equally well.
Is this not the case?
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The Sennheiser spec is at a volt, not a mW, as PJ mentioned above. Assuming I did the math correctly, that's about 98dB/mW. The Senns also cost about 3 times more than the entry Grados. I've never heard them, so they very well may sound 3 times better. But I'd assume if you're trying to make a Quickie into a headphone amp, the goal is to keep costs low.
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With my quickie the volume is close to being maxed out, but Grados are all about texture and detail not loud volumes and head thumping dynamics so its not a problem for me.
The output transformers have multiple output taps so you can experiment and find the ones that work best for whatever headphones you are using.
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The Sennheiser spec is at a volt, not a mW, as PJ mentioned above. Assuming I did the math correctly, that's about 98dB/mW. The Senns also cost about 3 times more than the entry Grados. I've never heard them, so they very well may sound 3 times better. But I'd assume if you're trying to make a Quickie into a headphone amp, the goal is to keep costs low.
That 112db spec is in mW, I believe. At volt it is much lower. The latter is what Senn have on their site.
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Here's where I pulled the volt reference from. http://en-us.sennheiser.com/audio-headphones-high-end-surround-sound-hd-598 (http://en-us.sennheiser.com/audio-headphones-high-end-surround-sound-hd-598)
Sound pressure level (SPL) 112 dB (1 kHz/1 Vrms)
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Here's where I pulled the volt reference from. http://en-us.sennheiser.com/audio-headphones-high-end-surround-sound-hd-598 (http://en-us.sennheiser.com/audio-headphones-high-end-surround-sound-hd-598)
I stand corrected.
So I ask again: what decent phones are above 108db?
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A follow up on this. The transformers have T7010 on them. These aren't the Specos?
Ah, sorry, mixing up 2.0 and 2.1
Did you end up cutting off the 500 Ohm taps by accident? (I think that was the brown wire?)
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Nope. All the wires are in tact.
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Ah, OK, well, that is the tap that we typically used, wired as an autoformer with the whole primary winding involved. This makes essentially a 4K:250 transformer, which means that high impedance and high efficiency headphones are a good match.
I haven't tried Grados on the lower taps myself, but my gut feeling is that there won't be enough power available for them, but your mileage may vary.
-PB
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THe problem with the Specos is that there were two versions, both with the same part number. The large Speco was about 2.2 inches between mounting holes, the small one 1.8 inches. I believe I have posted wiring and impedances for each of them.
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You did indeed...
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fbottlehead.com%2Fsmf%2Findex.php%3Faction%3Ddlattach%3Btopic%3D5829.0%3Battach%3D5080%3Bimage&hash=1bd5b752393d770191d8fa7102e5b9f3ee0e2fbf)
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A pretty decent sounding pair of headphone with high sensitivity and high impedance; I would suggest Urbanears Plattan. You can find them in stock at most BestBuys. You can find great deals online if color is not important. Plattan specs: sensitivity=115db; impedance=60ohms.
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impedance=60ohms.
For the Speco modified Quickie, 250 Ohms is a good starting point.
-PB
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For the Speco modified Quickie, 250 Ohms is a good starting point.
-PB
That would be the "old speco" ... the "new" version should drive 60 ohms quite well.
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115dB/...?
Unspecified specifications are so fun!