Just to follow up, I made a request and then filled out all the info requested then called and gave my credit card info. They emailed me back the same day.
David
David
They are available from Jensen direct - yes, their website is a bit odd, but they are great to deal with. Send an email or call.
PCB bundled with the Jensen transformers should be in the store this week.
PCB bundled with the Jensen transformers should be in the store this week.
Quick F6
Last week I received the DIYAudio F6 boards. Almost all components were in the drawer, so I couldn't resist to do a quick build by placing the F6 in the F5 enclosure.
Thanks to the Universal Mounting Specification, I could swap boards easily.
Aleph J was in the same chassis before 😉, and just had to drill and tap one extra hole in the heatsink.
I've used the original Toshiba JFET's, matched with Idss around 9,3 mA, a bit high, so they are getting nicely warm ( 56C).
For the electrolytic I 've used Panasonic FC bypassed with a small 10nF 1837 type polypropylene capacitor. Soldered underneath the PCB.
The 0.56 Ohm source resistor is made out of a 0.47 and 0.1 Ohm MPC74 resistor. I used 9.1 V zeners instead of 5.1 Volt.
MOSFETs are old matched 1999 International Rectifier ones.
Bias is stable with the LAB PSU's. And seems OK with the PSU's in the F5.
But I'm monitoring it right now...
Setting the bias is a bit slow due to the big capacitors in the amp, so beware not to make any big adjustments. I had the LAB PSU's current limited at 2.0 Ampere, luckily....
I expected it to be a bit noisy and have some hum picked up by the Jensen, but not at all, it's dead quiet, even with my ear at the tweeter.
The 3U -300 chassis is a bit too small for these PCB's, because the MOSFETs are not well spread over the heatsink. The one in front is getting 72C at the plastic body. So it's better to use a 4U -400 chassis.
First listening impressions are a very big soundstage (like Sony CSX1 VFET, maybe the Jensen transformers are what you are listening to 😀 ), very detailed and a good bass. So it's a promising amplifier.
Of course some pics:
Last week I received the DIYAudio F6 boards. Almost all components were in the drawer, so I couldn't resist to do a quick build by placing the F6 in the F5 enclosure.
Thanks to the Universal Mounting Specification, I could swap boards easily.
Aleph J was in the same chassis before 😉, and just had to drill and tap one extra hole in the heatsink.
I've used the original Toshiba JFET's, matched with Idss around 9,3 mA, a bit high, so they are getting nicely warm ( 56C).
For the electrolytic I 've used Panasonic FC bypassed with a small 10nF 1837 type polypropylene capacitor. Soldered underneath the PCB.
The 0.56 Ohm source resistor is made out of a 0.47 and 0.1 Ohm MPC74 resistor. I used 9.1 V zeners instead of 5.1 Volt.
MOSFETs are old matched 1999 International Rectifier ones.
Bias is stable with the LAB PSU's. And seems OK with the PSU's in the F5.
But I'm monitoring it right now...
Setting the bias is a bit slow due to the big capacitors in the amp, so beware not to make any big adjustments. I had the LAB PSU's current limited at 2.0 Ampere, luckily....
I expected it to be a bit noisy and have some hum picked up by the Jensen, but not at all, it's dead quiet, even with my ear at the tweeter.
The 3U -300 chassis is a bit too small for these PCB's, because the MOSFETs are not well spread over the heatsink. The one in front is getting 72C at the plastic body. So it's better to use a 4U -400 chassis.
First listening impressions are a very big soundstage (like Sony CSX1 VFET, maybe the Jensen transformers are what you are listening to 😀 ), very detailed and a good bass. So it's a promising amplifier.
Of course some pics:
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Walter - your construction looks fantastic! Congratulations!!! 🙂 😀 🙂 😀 🙂 😀 🙂
It's also very good to learn that you are not having any issue with induced hum into the signal transformers. This is good news for all builders.
Your impression of the sound is very similar to mine - very big, wonderful soundstage, great control. This is going to be a popular amp, most certainly.
It's also very good to learn that you are not having any issue with induced hum into the signal transformers. This is good news for all builders.
Your impression of the sound is very similar to mine - very big, wonderful soundstage, great control. This is going to be a popular amp, most certainly.
Great work again Walter!
I'm curious if something like a copper heat spreader will be useful in this instance.
Thanks,
Dennis
I'm curious if something like a copper heat spreader will be useful in this instance.
Thanks,
Dennis
You are correct - there is no link on the drop down menus. Somebody should fix that.
F-6 Kit PCB+Jensen Transformers - Power Amplifiers - Circuit Boards
F-6 Kit PCB+Jensen Transformers - Power Amplifiers - Circuit Boards
You're lucky. The whole store has stopped responding for me. Happened when the matched FETs were released too... I may miss this as well if the pages won't load in the next hour.
oo no, another poison again? I wish that diyaudiostore can declare lower value, i just cant have 1day leave to deal with customs office. or anyone is willing to help me buy one from the store and send it to me?
is there any reason not to build this compared to AlephJ or SIT L'amp?
😀
is there any reason not to build this compared to AlephJ or SIT L'amp?
😀