Have a look at the schematic of the Ampdesign KHV-88:
https://www.ampdesign.de/PP25/Kopfhoererverstaerker-KHV-88
Website is only in German, unfortunately.
That kit was my first valve amp project. It was a good clean build, and the amp still works very well and sounds great with both my Sennheiser HD600s and AKG K701s.
As the main valves, anything from ECC88 to ECC99 / 6N6Pi or 6N23Pi works great. For the first valve, I used from ECC83 to 5751 to 6N2Pi.
All the best, Claas
https://www.ampdesign.de/PP25/Kopfhoererverstaerker-KHV-88
Website is only in German, unfortunately.
That kit was my first valve amp project. It was a good clean build, and the amp still works very well and sounds great with both my Sennheiser HD600s and AKG K701s.
As the main valves, anything from ECC88 to ECC99 / 6N6Pi or 6N23Pi works great. For the first valve, I used from ECC83 to 5751 to 6N2Pi.
All the best, Claas
Wheatfiled HA-2 is still my favorite headphone amp for my HD-650’s ( Same impedance as the HD-600 at 300R)
Schematic is at the end of the manual.
http://www.pmillett.com/Wheatfield/manual.pdf
Schematic is at the end of the manual.
http://www.pmillett.com/Wheatfield/manual.pdf
I just built a headphone amp with a simple generic parafeed circuit. Very similar to Jim Hagerman's Tuba but with different parts. If he's still doing kits that's an option. In my case I used a couple of mains toroids as OPTs, 230v/12+12v. This gives me 9.6:1 step-down and sounds excellent. Many choices for a plate choke. Jim uses a Hammond 157G, and you could use Hammond 126B or 126C with just the primary connected. I like using Russian teflon coupling capacitors, but a good polypropylene would be OK. I used a 6N30 but plenty of alternatives for a mu of 1K to 2.5K. Care should be taken with high gain tubes to avoid oscillations - grid stoppers, ferrite beads etc. Oscillations would be a health risk for tinnitus in a head amp.
So here's the circuit. I used a separate PSU with tube rectifier, choke input and all polypropylene caps.
So here's the circuit. I used a separate PSU with tube rectifier, choke input and all polypropylene caps.
Attachments
I built this years ago for the Sennheiser HD800, but since the impedance of the headphones is about the same it will suit the HD600 just fine.
C3G Single Ended Triode - Original-Ton
C3G Single Ended Triode - Original-Ton
I’ve been experimenting with HPA for some time now. My preferred topology is a hybrid mu-follower with parafeed output into a step down transformer.
If you are an experienced builder and you’re prepared to adventure in DHT, then you should try the 2P29L:
Iron and Sand – Bartola(R) Valves
Several builders in the UK have already built it with a lot of success. We even did a shootout in London time ago and it was the clear winner.
There is a simpler implementation with IHP (triode strapped). Even if you can’t buy the transformer, you can drive the HP directly with the hybrid mu-follower. Mind you that distortion is higher and the coupling cap is somehow expensive if you want to add a good quality film or oil cap. Sound wise, it’s close the DHT with transformer but not the same for sure:
6e6p-dr Headphone Amp – part 3 – Bartola(R) Valves
I tried 6e6p-dr, 6e5p, D3a and E282F. All great options. E282F being my preferred one.
Hope this helps
Ale
If you are an experienced builder and you’re prepared to adventure in DHT, then you should try the 2P29L:
Iron and Sand – Bartola(R) Valves
Several builders in the UK have already built it with a lot of success. We even did a shootout in London time ago and it was the clear winner.
There is a simpler implementation with IHP (triode strapped). Even if you can’t buy the transformer, you can drive the HP directly with the hybrid mu-follower. Mind you that distortion is higher and the coupling cap is somehow expensive if you want to add a good quality film or oil cap. Sound wise, it’s close the DHT with transformer but not the same for sure:
6e6p-dr Headphone Amp – part 3 – Bartola(R) Valves
I tried 6e6p-dr, 6e5p, D3a and E282F. All great options. E282F being my preferred one.
Hope this helps
Ale
Hello Ale
So far in parafeed I've tried out the 6N30 (mu=15) and 6J1P (mu=28) and I have more than enough gain. So next step will be a 4P1L (mu=11). I'm not sure why you didn't use 4P1L instead of 2P29L? I have both, so can try out the difference. I'm hoping for enough gain so I can use a DHT. I'm still using plate chokes since I have some nice ones. With a gyrator I'm even wondering if I could use a 26 at 7mA current? That would be nice.
So far in parafeed I've tried out the 6N30 (mu=15) and 6J1P (mu=28) and I have more than enough gain. So next step will be a 4P1L (mu=11). I'm not sure why you didn't use 4P1L instead of 2P29L? I have both, so can try out the difference. I'm hoping for enough gain so I can use a DHT. I'm still using plate chokes since I have some nice ones. With a gyrator I'm even wondering if I could use a 26 at 7mA current? That would be nice.
Hey Andy
The gyrator load (or a CCS alternatively) will work better than a choke load in my opinion considering the load and the rp of the valve. However, if you have the right (and good quality) choke at hand, it will work well. I prefer the sound of the hybrid mu-follower as you know.
I chose the 2P29L as I love the sound and was keen not to fight with the microphony of the 4P1L. Just lazy I guess, as probably with the step down in place the microphonic noise will be tamed probably to a degree that isn’t a problem. Never tried.
A 26 at 7mA? Hmm need to look at the load line to see if it’s workable. Depends on load, step down and what signal level you have.
Ale
The gyrator load (or a CCS alternatively) will work better than a choke load in my opinion considering the load and the rp of the valve. However, if you have the right (and good quality) choke at hand, it will work well. I prefer the sound of the hybrid mu-follower as you know.
I chose the 2P29L as I love the sound and was keen not to fight with the microphony of the 4P1L. Just lazy I guess, as probably with the step down in place the microphonic noise will be tamed probably to a degree that isn’t a problem. Never tried.
A 26 at 7mA? Hmm need to look at the load line to see if it’s workable. Depends on load, step down and what signal level you have.
Ale
Ah - that makes me feel better about using the 4P1L. Sounds very nice in my latest version. No microphonics. I've been posting my results on another thread I started - DIY parafeed headphone amp - if you want to look at the circuit.
26 is always going to be a valve I'd be happy to try out. But as I say in the other thread, 24mA through the 4P1L does seem to give a cleaner sound.
26 is always going to be a valve I'd be happy to try out. But as I say in the other thread, 24mA through the 4P1L does seem to give a cleaner sound.
This works very well with my hd600 : DIY Audio Projects Forum • 6DJ8 (ECC88) Tube Headphone Amp Project
I built this as well. As above, I use it with the HD 600s. One of my finest sounding amps. You have a choice of output transformers for lower ohm phones.
Me
Stixx,
I enjoyed looking at your website. Very interesting! Admired your skill in making and creativity in design of your housings of the amps.
Since you have several very good headphone amp implementations I was wondering if the one you posted with the C3g is your favorite of all. I might try it since I have several NOS C3g in storage. When clicked the schematic you posted shows a “schematic not final” message in the lower left corner. Do you have a final schematic to share?
Thanks,
Francois
Ale, if you happen to check this thread…
Hi, Ale,
I’m curious as to whether you’ve evaluated the sound of your 2P29L based Headphone amp both with, and without the parafeed Sowter headphone transformer, but in Line-Level preamp application? I’m wondering whether you found the sound quality with the parafeed transformer as preferred to without it in preamp use?
I’m aware that the current increase enabled by the transformer isn’t needed for a preamp. I’m curious about the transformer’s affect on line-level sound quality. Thanks.
Hi, Ale,
I’m curious as to whether you’ve evaluated the sound of your 2P29L based Headphone amp both with, and without the parafeed Sowter headphone transformer, but in Line-Level preamp application? I’m wondering whether you found the sound quality with the parafeed transformer as preferred to without it in preamp use?
I’m aware that the current increase enabled by the transformer isn’t needed for a preamp. I’m curious about the transformer’s affect on line-level sound quality. Thanks.
why to waste ll1660 interstage as a choke?
rather use https://www.lundahltransformers.com/wp-content/uploads/datasheets/2765.pdf
https://www.lundahltransformers.com/wp-content/uploads/datasheets/2774.pdf
Hi Ken
Yes and my preference is parafeed. Without parafeed distortion is higher as expected but still very good sound. However the quality of the coupling cap then is important and if you’re spending money on it, perhaps is more sensible to get a parafeed OPT.
Cheers
Ale