Looking good..:thmbsp: cdfac is the one that brought the ebay source to my attention on the vampirewire stuff.
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Nelson Pass F5 build, Part Trois...
- Thread starter westend
- Start date
Looking good..:thmbsp: cdfac is the one that brought the ebay source to my attention on the vampirewire stuff.
specialidiot
Break Glass, Smoke Lucky
Lance, I succumbed to the piggy for about a week. I missed work Tuesday through yesterday - first illness related absence in about 5 years I guess. I went through a large box of tissues in a day and a half and sported a 102 fever. Lots of sleep, liquids, and vitamin D. Try to keep the fever knocked down with Tylenol.
I like those Vampires. My binding posts were backordered so I started with the generic Parts Express offerings but about a month ago installed some nice ones from Cardas.
rest up and get well my friend.
westend
Audiopile
Well, you both done good, the Vampirewire jacks are good quality. I even picked up some interconnect ends that were a steal, IMO. I believe the seller has sold off most of the jacks but still has listed some good deals on wire products.
Thanks for the sympathy, Jeff. I haven't been sick for so long, I forgot what it was like. I'm guessing that we are experiencing new strains of virus, here. I've got to rethink my attitude on flu shots
.I did do some amp-building-therapy, put the rectifiers in, powered up the transformer, and voltages look good. I was going to start populating the boards but I am missing the resistors for the PS board (back order from Digikey) and my kits from Tech-DIY had the wrong resistor count and values. I sniffled around and went back to bed.:sigh:
westend
Audiopile
Thanks, Nate, the metal work is the fun part of this.
I made some progress in the last couple of days, populating the boards, making the standoffs, and mocking up the locations. Pics are attached.
I did have a bit of confusion with the Tech-DIY kits. I'm thinking that Jack had a newbie on the packaging line. I should have carded the components, entirely, when I received them and that would have eliminated a lot of confusion, reordering, and waiting for parts to arrive. Jack has sent me all the missing and different values of parts in a very timely manner. I'm sure my level of frustration is well below his. The guy ships good small parts and is doing the DIY community a tremendous favor by assembling all that is necesary for a quality build. At this time, I'm waiting for the last few resistors to arrive from Digikey to populate the last few spaces on the boards and looking forward to firing up this badboy :yes:.
I will post a BOM when I have received everything, in hand. I ordered all the small parts from Digikey so other builders may benefit from a one-shipment/one-vendor order.
I made some progress in the last couple of days, populating the boards, making the standoffs, and mocking up the locations. Pics are attached.
I did have a bit of confusion with the Tech-DIY kits. I'm thinking that Jack had a newbie on the packaging line. I should have carded the components, entirely, when I received them and that would have eliminated a lot of confusion, reordering, and waiting for parts to arrive. Jack has sent me all the missing and different values of parts in a very timely manner. I'm sure my level of frustration is well below his. The guy ships good small parts and is doing the DIY community a tremendous favor by assembling all that is necesary for a quality build. At this time, I'm waiting for the last few resistors to arrive from Digikey to populate the last few spaces on the boards and looking forward to firing up this badboy :yes:.
I will post a BOM when I have received everything, in hand. I ordered all the small parts from Digikey so other builders may benefit from a one-shipment/one-vendor order.
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westend
Audiopile
The design calls for two NTC thermistors to be placed on the AC circuit. I have them on hand and will be connecting them on the transformer primaries. I believe I should mount them on some sort of terminal for safety concerns. I had thought about soldering them onto the transformer leads. What do you think?
The amp boards have current limiting and feedback circuits that protect against any DC to the outputs.
Thermistors have been installed on the primary transformer lines for a softer start. I'm really tickled with this particular piece, using part of the plastic display hanger of a Craftsman ratchet for the terminal cover.
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Russellc
Addicted Member
Here's my first few parts installed, I was missing to pots in one of the kits, but I've emailed and all should be well. These cards are really tiny, actually smaller than a business card.
Question: Are you guys using the standard values for R11 and R12, R5 and R8,
R1 and R2, or going with the modified feedback, 1 ohm for R11 and R12, 100 ohm for R5 and R8, 22 ohm for R1 and R2 suggested by Nelson Pass?
Allegedly makes the amp a little more full and warm. Some posters think it may go a little to far....
Russellc
Question: Are you guys using the standard values for R11 and R12, R5 and R8,
R1 and R2, or going with the modified feedback, 1 ohm for R11 and R12, 100 ohm for R5 and R8, 22 ohm for R1 and R2 suggested by Nelson Pass?
Allegedly makes the amp a little more full and warm. Some posters think it may go a little to far....
Russellc
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qboneus
Senior Member
I bought a few of these when i ordered parts for my f5, they are certainly cool and 'might' just be the ticket for your board... check them out!
here they are.@ 1/16 thick if you are interested.
this project looks great!!!
cheers,
tal
westend
Audiopile
I'm going with the original design values. I had forgotten about the 10 ohm to 22 ohm conversion. I might give that a whirl.
No problem with reworking his designs. My take is that he likes different ideas and implementaions using his designs.Who am I to second guess Nelson..
Exactly, the F5 is so easy to rework. There is basically nothing in the way to prevent tweaking the circuits at a future time. If the sound is not what you like, change a few things and experiment. I'm thinking that the original design is going to work out well.
westend
Audiopile
Thanks, Gary.
It sounds like I might be able to get ahold of some of that "stimulus" money after all, then.
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Aren't R11 and R12 the mosfet source resistors? I think going to 1 ohm would lower damping and provide less output power.
I stuck to stock values for the feedback stuff, I changed the values R21 and R22 to 22k. I haven't tested to see if my protection actually works though - testing it might cause some damage if it doesn't. I am pretty careful not to short the outputs.
I haven't seen the suggestions to change the feedback except by people trying to get a little more gain; though I have read all 550 pages of the F5 thread I could easily have missed it. If you know the post number (or general range) where it was discussed, I would like to take a look at it.
If you are using the PDaniels board like I did, make sure you install R5 - R8 into the correct holes or you will end up with no feedback like I had. Use the holes outside the resistor outline.
Russellc
Addicted Member
Ask Nelson, it was his idea, he says to make the amp a little less clinical and a little more warmth. You must have missed it. Others comment it goes to far in the other direction.
Russellc
Russellc
Addicted Member
With the 100 ohm 3 watt blue panasonics, I had no choice but to go with the
"longer" holes.... What resistors did you use, or did you stand them up? I would have assumed the "shorter" hole would have worked, did you ask Peter about that?
I'll try to locate the post by Nelson about the feedback, I took notes during my read to try to simplify finding things during construction. I'll post pics of the stuffed boards.....
Russellc