Hi Gavin, do you think it will still sound good with 32 ohm Grados? Mine has 32 and 300 ohm tap and the 300 ohm is not so good with my SR80i. I use the 300 ohm tap with AKG K240M (not mine) and it sounds good enough to me.
arnoldc said:
It's not really what the tap says it's the ratio of the windings. Yes I think it will sound good. Here is a schematic I threw together, I am assuming (always a mistake) that the CCS will take up half of the B+ leavin 180 v - 200 v for the 5687. I may be wrong and if I am then you can rest assured that smarter people than me will point the mistakes out. This is just a starting point. I think it will have enough gain. I've had a few scotches so I might be totally off base.
After looking at it again I'm not sure that this amp will be acceptable for a Grado. It will have no damping. A cathode follower output stage, direct coupled, could be added for use with Grados.
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Hi Gavin, did you mean omitting the output transformer altogether and using a big cap on the cathode output?
I was not and I think, I'm still not to keen on OTL with such a big capacitor 🙁
I was not and I think, I'm still not to keen on OTL with such a big capacitor 🙁
For parafeeding for Grados, lundahl LL1930's can work and aren't too expensive. Otherwise, Hammond 119DA, are OK. I got some Electra-Print 5K:32 parafeeds made for $100. You can also use power toroids. http://www.ecp.cc/less-pressivo-build.html
I built a 6SN7 / 6BL7 headphone amp designed by Eric Barbour a few years back.
http://headwize.com/projects/showfile.php?file=barbour_prj.htm
It was also published in Glass Audio.
I really like the sound and it drives my Sennheiser HD545 (150 ohm) headphoens without problems.
I did actually redesign the power supply to SS, a lot simpler, and just used components I had on hand.
http://headwize.com/projects/showfile.php?file=barbour_prj.htm
It was also published in Glass Audio.
I really like the sound and it drives my Sennheiser HD545 (150 ohm) headphoens without problems.
I did actually redesign the power supply to SS, a lot simpler, and just used components I had on hand.
arnoldc said:
I would use the transformers that dsavitsk suggested. The Electraprints. $100 for a pair is a great price. I would also use the SCVS that Wavebourn posted. THe schematic I drew up is just a starting point. The cap size was just a guess. A smaller one may work fine.
Alright G, folks, thanks much. 😀 After years of satisfaction, I'm looking at some ways to upgrade or change my headphone amp 😉
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