This build is no small task and I am saving up for heatsinks and transformers and other stuff. I can't plunk down $1K to $2K right now all at once, the wife might notice.
Besides I will build the V2 first.
Even that will be a few months in the making, for me and the time I have to put into it. I guess the reason I am writing this, is I feel bad no one is jumping at this opportunity and I really don't want this to die!
Rush
I would like to prototype 2 configurations, in priority order:
1. A balanced V2 using 4 x single FET output boards and the balanced input board.
2. The combined V2 combo board
I will test with bench power supplies, but I wouldn't object to testing a power supply board.
It might be a while before I complete all of these tests. If there is a shortage of boards for testing, my list is in order of preference.
I forgot to mention that my interest is not so much for high output power, but for low noise and distortion. I would like a 2nd generation balanced F5. I am not really interested testing in the Turbo diodes.
UKToecutter:
I should have pointed you to this post by Patrick (EUVL) showing the board layout for prototype F5X. It shows careful attention to component placing to minimize crosstalk and thermal effects. In my opinion it is a layout style to be emulated.
http://www.diyaudio.com/forums/pass-labs/121228-f5-power-amplifier-119.html#post1538826
I should have pointed you to this post by Patrick (EUVL) showing the board layout for prototype F5X. It shows careful attention to component placing to minimize crosstalk and thermal effects. In my opinion it is a layout style to be emulated.
http://www.diyaudio.com/forums/pass-labs/121228-f5-power-amplifier-119.html#post1538826
I found earlier posts about SPICE simulation of X vs balanced (Zinsula):
http://www.diyaudio.com/forums/pass-labs/121228-f5-power-amplifier-120.html#post1538833
http://www.diyaudio.com/forums/pass-labs/121228-f5-power-amplifier-13.html#post1485677
^^Andy, I may have to drop my interest and opt for the F5Vc boards from the DIYA store, those have the devices spaced exactly as I need them to be and away from the input stage. They don't have the room for the diodes but this is DIY so I'll probably mount them underneath the board.
I really appreciate the effort you're putting in to make this happen and I know it's impossible to please everybody - since the majority seem to want the devices placed this way, you should stick with it
Sangram
I really appreciate the effort you're putting in to make this happen and I know it's impossible to please everybody - since the majority seem to want the devices placed this way, you should stick with it
Sangram
Your option 1 is very similar to what I am wanting to build (except I would be using 8 single FET output boards per channel). I've realized that I don't need to cascode as the rails on the balanced build are going to be half that of an equivalent power single-end amp. I'm thinking of shooting for +/-24V rails which should be well within the safe limit for the JFETs.
I have ideas for 3 versions of the balanced F5T:
- Balanced stereo at 46W/channel using 2 x 1/2 E007 heatsink with fan as shown in http://www.diyaudio.com/forums/pass-labs/121228-f5-power-amplifier-1021.html#post2453420.
- Balanced stereo at 100W/channel using 2 x E007 heatsinks fin-to-fin with 2 fans.
- Balanced monoblock at 200W/channel using 2 x E007 heatsinks fin-to-fin with 2 fans.
Heatsink Sim
Hey Ihquam,
I was thinking about up a similar forced air build. Where did you get the heatsink simulation software from?
Thanks,
Steve
Hey Ihquam,
I was thinking about up a similar forced air build. Where did you get the heatsink simulation software from?
Thanks,
Steve
Prototyping doesn't necessarily mean doing everything all nice and tidy.
If you can get the front end, and maybe a pair of outputs working on a channel with a MUR3020, I say it's good to go.
Some of it is about component stuffing to make sure things in reality put together fairly easily and precisely.
If you can get the front end, and maybe a pair of outputs working on a channel with a MUR3020, I say it's good to go.
Some of it is about component stuffing to make sure things in reality put together fairly easily and precisely.
Aye Tea-Bag (love the id btw (being a yorkshire man and all)).......I've done proto work on 2 and 4 stroke porting, but its been a while since I've built an amp. V2 would allow me to help proto and if it works as a single channel, i'd have a ps only needing a second channel to be added.
My offer still stands.
My offer still stands.
Folks:
As excited as I am about this project, I confess that my confusion about how to heatsink a 100w/ch F5T is leading me to second-guess reserving V3 Output Boards; perhaps using the single FET output boards and spreading the heat across a larger physical space would be a more stable solution (but who needs a pair of HiFi2000 5U 500mm monoblock amps?). I've been spending a lot of time trying to identify adequate cost-effective solutions but am hampered by massive ignorance. My hope is that those of you who know what you are doing can provide some heatsinking guidance before Andy closes his pending group buy.
Regards,
Scott
As excited as I am about this project, I confess that my confusion about how to heatsink a 100w/ch F5T is leading me to second-guess reserving V3 Output Boards; perhaps using the single FET output boards and spreading the heat across a larger physical space would be a more stable solution (but who needs a pair of HiFi2000 5U 500mm monoblock amps?). I've been spending a lot of time trying to identify adequate cost-effective solutions but am hampered by massive ignorance. My hope is that those of you who know what you are doing can provide some heatsinking guidance before Andy closes his pending group buy.
Regards,
Scott
Hi Horio,
I'm probably wrong here, but at given heatsink capacity and given transformer VA rating, wouldn't single ended better in getting higher class A power, while balanced better in getting better overall power? Even though you get to use lower rail voltage at given overall taget power with balanced so higher bias current per device at given heatsink and transformer capacity, in SE mode 4 pairs of devices are in pararell adding up the current, while in balance mode there are only 2 of 2 pair devices in parallel to add the current against speakers? I'd appreciate your correction if I'm wrong.
Thanks!
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