[not sure if this should be in parts section but thought since it related to F5T and its PCBs I put it here]
I'm finally getting components and parts needed for an F5Tv2 build. One thing I'm struggling with are the miscellaneous parts, not so much components since I'm using the BOM. Could someone assist in the following:
- what, if any, terminal blocks required for this build? I looked on Digikey and I didn't realize there could be so many different sizes, types, configurations etc. I didn't see any in 6L6 illustrated guide so maybe I don't need them.
- Terminal strip for PSU? I saw a 4 pole strip used in 6L6 guide. What size though and what do I need to look out for. Max amp, I guess...
- What size stand offs for the F5T PCBs to connect to heat sinks do I get? I know M3 but the height/length is something I'm not sure about.
- I was going to get an assortment of M3 screws with hex head etc. Anything further I need to think about there?
- Apart from the above, is there anything that I am missing as far as parts for this project go?
I'm finally getting components and parts needed for an F5Tv2 build. One thing I'm struggling with are the miscellaneous parts, not so much components since I'm using the BOM. Could someone assist in the following:
- what, if any, terminal blocks required for this build? I looked on Digikey and I didn't realize there could be so many different sizes, types, configurations etc. I didn't see any in 6L6 illustrated guide so maybe I don't need them.
- Terminal strip for PSU? I saw a 4 pole strip used in 6L6 guide. What size though and what do I need to look out for. Max amp, I guess...
- What size stand offs for the F5T PCBs to connect to heat sinks do I get? I know M3 but the height/length is something I'm not sure about.
- I was going to get an assortment of M3 screws with hex head etc. Anything further I need to think about there?
- Apart from the above, is there anything that I am missing as far as parts for this project go?
You are lucky to be in the USA!
Every time I go to Ace Hardware, I am amazed at the assortment of screws, both metric and SAE. Stainless Steel, etc.
They have stand offs too.
You can bring parts in to help you decide what you need.
I like to shop locally as much as possible, or Amazon will take over all small businesses. And the option of holding something before you buy it will be gone forever.
Rush
no it's not.
I thought I could get a larger transformer in case i wanted to use it for more power later in another build or something. also thought that going a bit bigger (cost was marginal) the transformer could handle the power a bit more efficiently
Erlend - it certainly could go much higher! What bias is your amp set to? If bias is low the amp does not sound best.
Chuck d - if you use the cascode transistors in the front end, it will be able to handle higher voltages. Those transistors effectively make it a v3, regardless of how many output transistors you use. That’s what mighty Zen Mod was hinting at. 🙂
Up to what my heatsinks allows. 1.6 A 31 vdc. My Krell Clon KSA 100 MK 2 Pm 6 is incredible much better
1.6A per output pair, or 1.6A total?
I guess the first would be 50watts per device (which would be bloody hot), so I'll assume the second.
4 pairs of outputs? That's 0.4A per pair, which is on the low side. I think Nelson had his V1 running at 0.5A per pair, though, so not terribly low.
Still, I'd be aiming for more like double that.
I guess the first would be 50watts per device (which would be bloody hot), so I'll assume the second.
4 pairs of outputs? That's 0.4A per pair, which is on the low side. I think Nelson had his V1 running at 0.5A per pair, though, so not terribly low.
Still, I'd be aiming for more like double that.
Thanks Rush. I didn't think about local hardware. We only have HD close by. Not sure if they have stand offs. But they do have M3 hardware, I believe.
I ended up getting male/female 6mm/6mm brass standoffs from Amazon though.
Hey, guys! So, I’ve been a member of diy audio for almost a year, but I’ve never posted anything. I’m a long time fan of Nelson Pass and his creations in general. He’s a total rock star as far as I’m concerned.
I am gearing up to eventually buy the PCB’s, chassis, etc. to build an F5 Turbo V2 amp. I’ve done a lot of research and read pretty much any thread on the subject, but I’ve still got a quick question for anyone that could possibly help out.
What is the difference between an LSK170X-1 and the other LSK170 JFET’s produced by Linear Systems? Would it make sense to buy a bunch of the X-1’s to match them? Are those the highest quality of the bunch? As far as I can see, the specs are the same.
Thanks in advance to everyone at diy audio. It’s clear there’s a lot of great people here.
I am gearing up to eventually buy the PCB’s, chassis, etc. to build an F5 Turbo V2 amp. I’ve done a lot of research and read pretty much any thread on the subject, but I’ve still got a quick question for anyone that could possibly help out.
What is the difference between an LSK170X-1 and the other LSK170 JFET’s produced by Linear Systems? Would it make sense to buy a bunch of the X-1’s to match them? Are those the highest quality of the bunch? As far as I can see, the specs are the same.
Thanks in advance to everyone at diy audio. It’s clear there’s a lot of great people here.
Just a note that I was not comfortable using the input JFETS above their rated voltage and decided to cascode them. I selected BD139 and BD140 transistors. This device has different pinouts than stenciled on the F5 PCB. The heat sink side faces the other way. I think. I hope.
That would be my choice as of today....but with a choke input...than you will maybe have 35V afterwards, depending on the resistance of the coils which should have min. 10mH.
In my humble opinion, the word BURNING from Burning AMP is kind of philosophy of Mr. Pass Nelson designing and building his amps. F5 Turbo has to be burning to sound well.
I used all components from the store to build a F5 Turbo V2. As Mr. Pass Nelson described in his article, I started as a fraidy-cat, set Iq 0.6A (300mv cross MosFet S resistor, the rail is +/- 33VDC when loaded) per device, then listened it for few weeks. Compared with my KT88 50W Ultra-Linear amplifier clone (GEC, 1957), objectively, I felt the sound is little bit too sharp and bright. I was a little disappointed at the beginning, too.
Then I adjusted Iq to 0.75A (375mv) per device. Suddenly the sound became more neutral and warm. I am going to listen it for a while.
Since the temperature is not too high and I can hold my finger on the washer on the Mosfets forever, I plan to do a temperature measurement in the near future. If there is still room, my goal is to set Iq as high as 0.8-0.85A per device (400-425mv). Based on the diode curve provided by Mr. Pass Nelson, it could conduct less than 0.1A even the Tj=80C) and should be safe enough. I also bought BC3399-ND THERMISTOR NTC 4.7KOHM 3984K LUG and screwed them directly on the washer on the top of the mosfets. Iq actually reduces a little when the temperature raises.
I used all components from the store to build a F5 Turbo V2. As Mr. Pass Nelson described in his article, I started as a fraidy-cat, set Iq 0.6A (300mv cross MosFet S resistor, the rail is +/- 33VDC when loaded) per device, then listened it for few weeks. Compared with my KT88 50W Ultra-Linear amplifier clone (GEC, 1957), objectively, I felt the sound is little bit too sharp and bright. I was a little disappointed at the beginning, too.
Then I adjusted Iq to 0.75A (375mv) per device. Suddenly the sound became more neutral and warm. I am going to listen it for a while.
Since the temperature is not too high and I can hold my finger on the washer on the Mosfets forever, I plan to do a temperature measurement in the near future. If there is still room, my goal is to set Iq as high as 0.8-0.85A per device (400-425mv). Based on the diode curve provided by Mr. Pass Nelson, it could conduct less than 0.1A even the Tj=80C) and should be safe enough. I also bought BC3399-ND THERMISTOR NTC 4.7KOHM 3984K LUG and screwed them directly on the washer on the top of the mosfets. Iq actually reduces a little when the temperature raises.