Headphone Amp

Adrculda · 06:00 AM

Looking at a quick side project before i build the big amp...

Goals:
3-5W OPT
Balanced Input
Must be usable as preamp

Must be able to drive low impedance headphones...
Currently using Sony MDRV700 ( 24 Ohms )

Possible output tubes
6080 - 6C33C

ruffrecords · 28th August 2011, 11:15 AM

An ECC99 as an SRPP at about 15mA standing current driving a Sowter 8665 headphone transformer would do the job. A Sowter 10K:10K bridging transformer on the input, such as the 3293, will give you your balanced input.

Cheers

Ian

roline · 28th August 2011, 07:17 PM

Currently listening to a 6U10 or 6ac10's-Mosfet hybrid headphone amp.
6u10 is an input gain stage and SRPP second stage with a Mosfet follow output. I did allow for feedback from the output to the input of the SRPP stage. The output is cap coupled.
I was looking for a simple, inexpensive amp that could use what stuff I had on hand.
The tubes will be visible though a window in the front of the amp, the idea is to use 304 mirror finish to make a divider to reflect the light forward and hide the circuitry. I used foil glued to cardboard for a mock up...

Adrculda · 28th August 2011, 11:47 PM

Quote:

Originally Posted by ruffrecords

An ECC99 as an SRPP at about 15mA standing current driving a Sowter 8665 headphone transformer would do the job. A Sowter 10K:10K bridging transformer on the input, such as the 3293, will give you your balanced input.

Looking to stay away from transformers unless its for power...

Quote:

Originally Posted by roline

Currently listening to a 6U10 or 6ac10's-Mosfet hybrid headphone amp.
6u10 is an input gain stage and SRPP second stage with a Mosfet follow output. I did allow for feedback from the output to the input of the SRPP stage. The output is cap coupled.

Also Looking to stay away from SS components as well...

roline · 29th August 2011, 02:59 AM

Mosfet having the same trans-conductance, "voltage in, current out" as a tube and in a Class A follower application has the advantage of low output impedance over a tube....
I tried other ideas, came back to this one. The 6U10 is not the most ideal low voltage tube, but the results are impressive. Other ideas included 5 watt tube PP and SE circuits, but the transformers are very expen$ive for the bandwidth.
You might try a SRPP with a set of GU50's or KT88's

Adrculda · 03:10 AM

I'm looking at something similar to the Little Dot MK VI or MK VIII...
Sadly i cant find the diagrams :/

Even though the MK VI is more suited for my headphones

Wavebourn · 29th August 2011, 03:12 AM

Quote:

Originally Posted by Adrculda

Also Looking to stay away from SS components as well...

What about staying away from very non-linear power supply regulating tubes?

Adrculda · 29th August 2011, 03:28 AM

Quote:

Originally Posted by Wavebourn

What about staying away from very non-linear power supply regulating tubes?

But there are improved tube regulated power supplies

Wavebourn · 29th August 2011, 03:47 AM

Quote:

Originally Posted by Adrculda

But there are improved tube regulated power supplies

I would personally prefer 4P1L output tube with nice transformer, powered by MOSFET voltage regulator. Can't think of anything better for headphones.

Adrculda · 29th August 2011, 04:05 AM

What about 6C33C ?
They are low voltage and capable of delivering high current in PP OTL

28th August 2011, 05:36 AM	#1
Adrculda diyAudio Member Join Date: Jan 2009	Headphone Amp Looking at a quick side project before i build the big amp... Goals: 3-5W OPT Balanced Input Must be usable as preamp Must be able to drive low impedance headphones... Currently using Sony MDRV700 ( 24 Ohms ) Possible output tubes 6080 - 6C33C Last edited by Adrculda; 28th August 2011 at 06:00 AM.

28th August 2011, 11:15 AM	#2
ruffrecords diyAudio Member Join Date: Jun 2007 Location: Holt, Norfolk	An ECC99 as an SRPP at about 15mA standing current driving a Sowter 8665 headphone transformer would do the job. A Sowter 10K:10K bridging transformer on the input, such as the 3293, will give you your balanced input. Cheers Ian __________________ Ian

29th August 2011, 02:59 AM	#5
roline diyAudio Member Join Date: Sep 2010 Location: East Tennessee	Mosfet having the same trans-conductance, "voltage in, current out" as a tube and in a Class A follower application has the advantage of low output impedance over a tube.... I tried other ideas, came back to this one. The 6U10 is not the most ideal low voltage tube, but the results are impressive. Other ideas included 5 watt tube PP and SE circuits, but the transformers are very expen$ive for the bandwidth. You might try a SRPP with a set of GU50's or KT88's __________________ SO many tubes, SO little time!!!

29th August 2011, 03:07 AM	#6
Adrculda diyAudio Member Join Date: Jan 2009	I'm looking at something similar to the Little Dot MK VI or MK VIII... Sadly i cant find the diagrams :/ Even though the MK VI is more suited for my headphones Last edited by Adrculda; 29th August 2011 at 03:10 AM.

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29th August 2011, 04:05 AM	#10
Adrculda diyAudio Member Join Date: Jan 2009	What about 6C33C ? They are low voltage and capable of delivering high current in PP OTL

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