By dual mono I meant a box with holds two separate amps... each with its own power supply... doughnuts, etc...
My concern with yet another 5U-400 box is "where do I put this thing?" Heck, if you listen to ZM he'll tell you to get a 5U-500 box. As it is, my XA252 ended up like Swiss cheese with custom fully sloted top and bottom covers. You can see right through it.
My current F5 is built in a ....... "Rawson box"... with a shared power supply it's actually small. But I just bought the kit from the DIY Store and grabbed the dual power supply version.. so if I could make this on two smaller boxes.
That said, a 3U-400 will fit. There's an aluminum Dissipante 3U 400mm with the 10mm front panel that looks quite nice... in black. I don't think you can get handles for it. If I can get away with this size, that's the route I'd like.
https://modushop.biz/site/index.php?route=product/product&product_id=209
My concern with yet another 5U-400 box is "where do I put this thing?" Heck, if you listen to ZM he'll tell you to get a 5U-500 box. As it is, my XA252 ended up like Swiss cheese with custom fully sloted top and bottom covers. You can see right through it.
My current F5 is built in a ....... "Rawson box"... with a shared power supply it's actually small. But I just bought the kit from the DIY Store and grabbed the dual power supply version.. so if I could make this on two smaller boxes.
That said, a 3U-400 will fit. There's an aluminum Dissipante 3U 400mm with the 10mm front panel that looks quite nice... in black. I don't think you can get handles for it. If I can get away with this size, that's the route I'd like.
https://modushop.biz/site/index.php?route=product/product&product_id=209
go quad chassis: separate channels, separate power supplies. take it all the way.
Papas First Watt items only use one box and one transformer, sound plenty good. I have a pile of the clones. The idea of each morphing into four chassis is horrifying!
the joys of DIY. We're given the tools to take it as far as we want.
Quad F5m.... four chassis for two amps..... absolutely where I come from...
10 wpc, four 5U, 500 mm deep.
My wife and I were discussing adding two more rooms to our house. One will be my office/audio room. She asked me
"will that fit your stuff?"
Gentlemen... this is getting serious.
NCore serious
🙂 🙂 🙂
@Russellc Nelson has to deal with commercial realities... do we have to be realistic about such things? Perhaps we ought to limit ourselves to ten watts per box? Anyhow, I think I'll order a single 3U-400mm deep box.. I sure hope the dynamics are not constricted with such a limitation...
10 wpc, four 5U, 500 mm deep.
My wife and I were discussing adding two more rooms to our house. One will be my office/audio room. She asked me
"will that fit your stuff?"
Gentlemen... this is getting serious.
NCore serious
🙂 🙂 🙂
@Russellc Nelson has to deal with commercial realities... do we have to be realistic about such things? Perhaps we ought to limit ourselves to ten watts per box? Anyhow, I think I'll order a single 3U-400mm deep box.. I sure hope the dynamics are not constricted with such a limitation...
With that in mind, an experiment I once did a long these lines. I saw another members post, something about converting to mono blocks. He had two Pass clones and took one circuit board out of each, mixed them and arranged a switch that would send to juice to one board or the other.
I did this to my Aleph J and M2. Worked very well. However, after a while I began to miss something. More so with Aleph J than M2, but still. Finally I switched them back, and was happy again.
This is mostly personal taste to some extent, but I enjoyed the slightly warmer tone of the non mono block versions.
All these mods, along with arranging an amp to be balanced, X'd or bridged changes the distortion spectra. If you like it, great. I guess I prefer the original designers wisdom over mine.
If I want such an amp for more power, or whatever, I tend to go with zenmods babblefishing examples. He has the skill to set the distortion spectra accordingly. A skill set I don't have.
Russellc
Nelson's wife let him build a big room for his toys. And actually, we don't know what he's got into his room - well, he did have the El Pipos and those big Klein speakers... so maybe he does have some 1000 wpc six chassis balanced amps.....
My wife has started to mumble about having three racks and two sets of speakers in the living room.
I mean, she only has one rack and one rather BIG TV in her den.
Maybe I ought to move the Quad Chassis F5m4 into the den? The surrounds are discreet on the ceiling... you think she'd enjoy having four black surround speaker boxes hanging from the ceiling?
No, I think I'll order the smaller box. We got a target number to build the new rooms.
Discretion... discretion.
My wife has started to mumble about having three racks and two sets of speakers in the living room.
I mean, she only has one rack and one rather BIG TV in her den.
Maybe I ought to move the Quad Chassis F5m4 into the den? The surrounds are discreet on the ceiling... you think she'd enjoy having four black surround speaker boxes hanging from the ceiling?
No, I think I'll order the smaller box. We got a target number to build the new rooms.
Discretion... discretion.
go back to strength you had when 30yrs old, everything will be allowed
Hello i have a question for all the smart people on this forum. does resistor tolerance affect sound or anything important when used as a source resistor. for instance using a resistor with a 10% tolerance?
I had actually purchased 0.47 10% 3W Wirewound resistors. it appears the one included in the F5M kit are green Vishay wirewound resistors(going off of appearance cannot otherwise confirm). here is the link for the exact part i purchased:https://www.mouser.com/ProductDetail/71-RW69VR47
I don't get it... it seems like there are 0.1% tolerance resistors.... wirewound. Look at those 5w units...
https://www.mouser.com/c/passive-components/?resistance=1 Ohms&tolerance=0.1 %
Isn't this what we'd want as the output resistors? Did I misread the chart?
https://www.mouser.com/c/passive-components/?resistance=1 Ohms&tolerance=0.1 %
Isn't this what we'd want as the output resistors? Did I misread the chart?
I don't believe you need to spend $21 for each resistor for 0.1% tolerance. If you really wanted that tolerance, you could by 100qty 5% resistors and just match them to 0.1% with a multimeter yourself (assuming it can read that low of a resistance accurately, such as a 4 digit DMM) and still save a lot of money. The parts listed for the F5m are 5% tolerance, so that seems to be more than enough for this design. The "RW" Vishay's are a military grade resistor, which is often just a commercial resistor with dumbed down tolerances to ensure compliance to a military specification. So you can buy a $1 resistor that's 5% commercial grade sale, or you can buy the exact same resistor with a military spec for $3, that does nothing more than guarantee you are within the wider mil spec. You work in aerospace Tony, I'm sure you get that a part sold to an automotive store sells for 10x less than that same part sold to an aerospace company. The "paperwork" is what you're paying for when it comes to the "aerospace grade" (aka Mil Spec) part.
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The MIL SPEC parts cost a boatload indeed. That' what I used to use when I was building these things. At one job I was using 50W and 100W, precision resistors for current sensing... God Know how much those things cost...
However, even at 25 bucks a part, the end result amp is still dirt cheap compared to buying a bonafide Nelson Pass First Watt unit...
My point was that wirebound very high precision resistors do exist. And in this case, on the output side, with 1 ohm resistors, the highest precision is called for.
Of course, your idea of buying 100 resistors and matching them also makes sense. I guess you can put practicality over engineering orthodoxy.
By the way, I wonder why 5% is enough. With those very low resistance units, wouldn't you want to match them as close as possible? What will a 5% difference do between channels in term of performance?
However, even at 25 bucks a part, the end result amp is still dirt cheap compared to buying a bonafide Nelson Pass First Watt unit...
My point was that wirebound very high precision resistors do exist. And in this case, on the output side, with 1 ohm resistors, the highest precision is called for.
Of course, your idea of buying 100 resistors and matching them also makes sense. I guess you can put practicality over engineering orthodoxy.
By the way, I wonder why 5% is enough. With those very low resistance units, wouldn't you want to match them as close as possible? What will a 5% difference do between channels in term of performance?