Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: Applemacman on October 09, 2020, 12:54:37 AM
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Hi was looking for some help. After finishing my bottlehead crack I checked with ohm meter and all test points matched fine. So i proceeded to put the valves in and start the voltage tests. Both tubes glowed and then i noticed a small amount of smoke coming from around the transformer so qwickly unplugged the amp. Checked the fuse, which was ok it had not blown. Cant see anthing burnt. So turning to the forum for help does anyone have any advice?
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Maybe post some pics of the wiring, including a shot of the transformer wiring.
cheers, Derek
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Its ok i hv solved it. I stupily wired a capacitor atound the wrong way. Resoldered it correctly, plugged it in no smoke. So preceeded to check voltages and all match. So im good to go.
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Congrats on finding the problem! I would suggest posting a pic of the cap. If it is bulging (bent outwards at the top), it will need to be replaced.
cheers, Derek
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The cap is fine i checked it already there is no buldge at all Just one more question. Do I have to have a specific type of headphones? Im was trying to check the sound us a cheap pair I use for the pc but get no sound. Was wondering if this was due to the fact I hv to use a set with a specific criteria?
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Any headphones should make sound, but higher impedance (250+ ohms) will generally sound better. Does the amp pass the voltage checks?
If it passes the voltage checks, no sound is often a ground wiring problem -- a loose or missing connection. I'd suggest reflowing all black wire connections, with particular attention to the black wire connections at terminal 3, the volume pot, and the headphone jack.
cheers, Derek
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Ok i will check this later and come back. Thanks for advice
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Ive checked it. The wiring looks ok to me. I cant see anything wrong. Im using the headphones from a mobile because ive not brought a set of headphones yet. Ive traced the back wiring paying attention to the pot and headphone jack. Its looks fine. I have no idea why im not getting any sound.
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Can you post your voltages on terminals 1-10 and also some build photos?
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Pin 1 is 70 volts
Pin 10 is 0 volts
I cant seem to attach pictures ive tried jpg wont allow me
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picture of the build
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close picture of transformer area
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Pins 1-10 means one through ten, so 1, 2, 3, 4, 5, 6, 7, 8, 9, & 10.
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Your photos reveal that you have gone way off the beaten path with installing and wiring the headphone jack. If you redo that area and follow the instructions precisely in the manual, you will have sound coming out of your amp.
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Hi I cant believe i did that, redid it and it works. I think i will buy a new iphone jack and the resistors and some wire to redo it in the future. Thanks so much for your help.
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Anybody hv a recomendation for a good suitable headphone.
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I use Sennheiser HD600 headphones, and I think they sound good. Not too expensive.
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The Sennheiser HD 600/HD 650/HD 6XX (300 ohms) are definitely the most recommended & lauded--plus they're not too expensive. They have a neutral and laid-back sound IMO.
Whatever you do, make sure the headphones will pair well with the Crack, meaning that the headphones are at least 250 ohms.
Beyerdynamic DT 770 & DT 880 (250-and-600 ohms) are worth checking out too. They have a brighter sound signature, that fatigues me after a while.
If you're the frugal & tinkering type, vintage AKG K240 Monitors (600 ohms) can usually be had for around $50-80 on auction sites. With some cleaning up, new elastics, and Brainwavz hybrid pads, it's surprising the sound quality you'll get for not too much $$. They have a live and natural-sounding presentation.
Obviously, there are many more options--and many more expensive options--but the ones I listed are widely considered the sweet spot in terms of price and sound quality.
Happy hunting! :)
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Dear all,
I will look into the headphone recommendations. Just wanted to say thank you to all that helped me, its much appreciated. I thought id post my set up. Now im off to research the headphones and to enjoy some vinyl.
Linn LP12
Linn Akito Arm
Linn K9
Naim Armageddon
Naim Stagelin n
Bottlehead Crack headphone valve amplifier
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Anybody hv a recomendation for a good suitable headphone.
As others have mentioned, find something with impedance higher then 200 ohms, then you're sure the Crack can drive them with plenty of headroom and control.
Choice would be down to your preferences sonically.
I have tried my Crack+SB with following headphones: Sennheiser HD650; Beyer DT990 (lightly modded) and Beyer T1 2nd gen.
My DT990's are modded a bit with extra damping of the driver to take the "edge" of the normally quite hot/sibilant treble. But otherwise a great can if you like extra emphasis on the low end and treble. After around 15 years of use finally teamed by my T1 2nd gens.
HD650: They just sing with the Crack! Sound is to the "cozy" side, but very pleasing and musical. Personally I get a tiny bit bored though :)
T1 2nd gen: Beyer house sound again. If you can enjoy a bit of excess energy in the treble, then it's just a no-brainer to me. So entertaining presentation and details are presented so precisely. Very neutral bass presentation that extends all the way down.
I was very close to ordering a set of Beyer DT1990 Pro's but ended with the T1's. But I would urge you to check reviews of them. Seems tempting.