Just finished this circuit provided to me by John Broskie:
And with some valuable advise from members of this forum...
I am pleased to report that this design produces killer sound, with wide dynamics, extremely low noise floor (meaning I hear nothing at full volume wearing Sennhieser 595's with source paused), and final musical notes decay into an abyss of silence.
I decided to try simple, 6.0 volts AC on the filaments (NO HUMMM), tube rectified GZ-32,C-L-C-R-C power supply filter, power tranny stays around room temperature.
Easy to roll several tube types in the front section, 6N1P, ECC88, 6DJ8, etc.
Worthy of consideration for those interested in headphones.
dr._sleep
An externally hosted image should be here but it was not working when we last tested it.
And with some valuable advise from members of this forum...
I am pleased to report that this design produces killer sound, with wide dynamics, extremely low noise floor (meaning I hear nothing at full volume wearing Sennhieser 595's with source paused), and final musical notes decay into an abyss of silence.
I decided to try simple, 6.0 volts AC on the filaments (NO HUMMM), tube rectified GZ-32,C-L-C-R-C power supply filter, power tranny stays around room temperature.
Easy to roll several tube types in the front section, 6N1P, ECC88, 6DJ8, etc.
Worthy of consideration for those interested in headphones.
dr._sleep
I am using these, Sowter 8665 Headphone transformers
(http://www.sowter.co.uk/)and have used the same on other headphone amps with excellent results. Just under $100 a piece. They need to be cap coupled, there is 125 dc that has to be blocked.
But with 600 ohm impedance headphones you could go the OTL route taking the output right off the last coupling caps..
The results have been debated, but in the end it's a matter of personal taste.
I prefer transformers, others prefer the OTL route. A good 600 ohm impedance headphone are the AKG 240 M (Monitor) at only $100.00, but you could spend $400 on Senn's @600 ohms.
The transformers can be configured for 120 to 600 ohms impedance.
It sounds very fine, not even burned in.
dr._sleep
(http://www.sowter.co.uk/)and have used the same on other headphone amps with excellent results. Just under $100 a piece. They need to be cap coupled, there is 125 dc that has to be blocked.
But with 600 ohm impedance headphones you could go the OTL route taking the output right off the last coupling caps..
The results have been debated, but in the end it's a matter of personal taste.
I prefer transformers, others prefer the OTL route. A good 600 ohm impedance headphone are the AKG 240 M (Monitor) at only $100.00, but you could spend $400 on Senn's @600 ohms.
The transformers can be configured for 120 to 600 ohms impedance.
It sounds very fine, not even burned in.
dr._sleep
Thought I'd post a pic of the working, great sounding, headphone amplifier. A tweak or two left to do.
Schematic
Insides
Glowing on the outside
Very simple, no sand anywhere. Cost to build, $325.00 tubes not included.
Sorry I broke the link to the schematic in post #1 by sending up another one.
dr._sleep
Schematic
Insides
Glowing on the outside
Very simple, no sand anywhere. Cost to build, $325.00 tubes not included.
Sorry I broke the link to the schematic in post #1 by sending up another one.
dr._sleep
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