Old Git UK
New Head-Fier
I’ve always been impressed by these unusual headphones, but felt for a number of years they were underperforming. A year or so back I started to lose sound in the left channel which I initially thought was due to a poor contact. Having stripped them down I realised the fault lay with defective traces on the small pcb holding the female 3.5mm socket. I’m a firm believer in hard wiring where possible and this presented an easy solution to my problem. As can be seen the 10uF cap has been upgraded to a Nichicon. Had space not been an issue I would have preferred to have fitted a Wima Polyester but measuring 16x11x7mm there really wasn’t the space without chiselling out some of the Cherry wood cup. The chosen cable measures 125cm including the 45cm yoke and is a twisted weave to combat RFI. I prefer Occ copper for headphone cable as it typically gives warmth to the sound. This cable has higher tensile strength than others I’ve tried. Before closing up I added a small piece of 2mm thickness bitumen to help control reflections and temper any unwelcome resonance which had shown up on a frequency sweep. Since performing the work I’ve only run them for a few hours and on first impressions they sound jaw dropping. The clarity of the upper mids and treble is possibly up there with the best I have ever heard and I’m referring to the Stax Lambda and Sigma. The sound is now incredibly natural, as if I was listening to my Gale 401s and not a pair of headphones. These are now my new Reference phones being streets ahead of my other headphones (Hifiman Ananda/ Nakamichi HF-100/ Beyer DT-811). The JP1s can’t take all the credit as there is wonderful synergy between the Headphones, the modified Graham Slee Novo amp and its new 24Vdc power supply which benefits from 3 levels of filtration. The bank of capacitors do a remarkable job with filtration to provide a totally silent backdrop for the music.
Whereas the JP1 are unbeatable when listening to HiRes Flac and other digital sources, the Nakamichi HF-100s which are 16 Ohm are voiced specifically to mimic a pair of broadcast monitor speakers. They really excel with an all analogue signal and make late night listening to vinyl or cassette tapes and my Troughline FM valve radio a joy rather than a compromise. The HF100s are connected directly to a QED Speaker/Headphone switchbox which is fed from either my Crimson 630Ds or my lovely vintage Sugden A51 Class A power amp via the speaker output terminals.
The only other mod to the JP1 I’m considering is the Auto Rosen and Triple Accel driver and baffle damping
treatment. So far I’ve sent 2 requests and as yet I haven’t received a response from Rosen Kranz in Japan. It’s possible I’ll have to tweak the placement in view of the small piece of bitumen I’ve added to the inside of the Cherry cups.
Whereas the JP1 are unbeatable when listening to HiRes Flac and other digital sources, the Nakamichi HF-100s which are 16 Ohm are voiced specifically to mimic a pair of broadcast monitor speakers. They really excel with an all analogue signal and make late night listening to vinyl or cassette tapes and my Troughline FM valve radio a joy rather than a compromise. The HF100s are connected directly to a QED Speaker/Headphone switchbox which is fed from either my Crimson 630Ds or my lovely vintage Sugden A51 Class A power amp via the speaker output terminals.
The only other mod to the JP1 I’m considering is the Auto Rosen and Triple Accel driver and baffle damping
treatment. So far I’ve sent 2 requests and as yet I haven’t received a response from Rosen Kranz in Japan. It’s possible I’ll have to tweak the placement in view of the small piece of bitumen I’ve added to the inside of the Cherry cups.
Attachments
Last edited:
