Thank you and congratulations Brian and Meredith.
Health and happiness to you both on your wedding day.
Health and happiness to you both on your wedding day.
AJ Bertelson said:
The resistors were a bonus item included with some of the pcb sets. Here is some more information on them from the other thread:
http://www.diyaudio.com/forums/showthread.php?postid=356733#post356733
--
Brian
widman said:
Thank you, it should be a great weekend.
tiroth said:
Looks good. What kind of transformer is that?
--
Brian
It's a PC-mount Talema toroid. Very undersized as far as conventional wisdom goes, but I've found that you don't need a ton of VA for small mid/tweeter or surround amps.
Still no kit in Belgium. UPS's workdays are long 😉
Any other Belgian got his or her kit already?
Any other Belgian got his or her kit already?
Tiroth:
Can you post part nr. and where you baught the cabinet and the toroid? What do you use as a heatsink?
edit: (Looks like you're using the bottom of the cabinet)
Can you post part nr. and where you baught the cabinet and the toroid? What do you use as a heatsink?
edit: (Looks like you're using the bottom of the cabinet)
I'm signed up for the second round of kits - enjoying the progress of those built so far.
To those who have assembled kits, what is the board size, including height with BG caps?
Colin
To those who have assembled kits, what is the board size, including height with BG caps?
Colin
Alcaid said:
Cabinet is Hammond 1455 series, sourced from Mouser. There are some even nicer extruded-type enclosures sold in Europe, I believe...I've wished that they were sold in the states.
http://www.hammondmfg.com/1455.htm
The toroid is a 25VA 2x15v sourced from Digikey.
http://www.amveco.com/Low_Profile_PC.htm
Purpose of R2?
I realize this is a little late in the game to ask such a question, but what is the purpose of R2 when using the amp with an input volume control? Looking at the National spec sheet, R1 (Rb) is used to: "Prevents currents from entering the amplifier’s non-inverting input which may be passed through to the load
upon power-down of the system due to the low input impedance of the circuitry when the under-voltage
circuitry is off. This phenomenon occurs when the supply voltages are below 1.5V." But they don't have an eqivalent to R2. From the previous answers I got from Brian and Peter, R2 is used to set the input impedence of the amp when used as a straight power amp, but wouldn't it affect the curve of the pot when one is used? I seem to remember someone (Thorsten?) using a linear pot and a resistor to make a log pot??
David
I realize this is a little late in the game to ask such a question, but what is the purpose of R2 when using the amp with an input volume control? Looking at the National spec sheet, R1 (Rb) is used to: "Prevents currents from entering the amplifier’s non-inverting input which may be passed through to the load
upon power-down of the system due to the low input impedance of the circuitry when the under-voltage
circuitry is off. This phenomenon occurs when the supply voltages are below 1.5V." But they don't have an eqivalent to R2. From the previous answers I got from Brian and Peter, R2 is used to set the input impedence of the amp when used as a straight power amp, but wouldn't it affect the curve of the pot when one is used? I seem to remember someone (Thorsten?) using a linear pot and a resistor to make a log pot??
David
Forget the linear pot, it's curve is not very appropriate for good control range with NI amp.
R2 (20k approx) is necessary when using a pot value bigger than 20K, as without resistor the DC offset may increase substantially (300mV or so). If your pot is 20K or less, this resistor is not really necessary. However, I noticed that adding Caddock 22k to a pot (in parallel), somehow improves the sound, so experimenting here is recommended. You might like it more with resistor in place.
I'm using this resistor with 50k Nobel pot (log) and I didn't notice any degradation in control range.
R2 (20k approx) is necessary when using a pot value bigger than 20K, as without resistor the DC offset may increase substantially (300mV or so). If your pot is 20K or less, this resistor is not really necessary. However, I noticed that adding Caddock 22k to a pot (in parallel), somehow improves the sound, so experimenting here is recommended. You might like it more with resistor in place.
I'm using this resistor with 50k Nobel pot (log) and I didn't notice any degradation in control range.
I wouldn't
"Forget the linear pot, it's curve is not very appropriate for good control range with NI amp."
What are you talking about? This depends on signal levels form the
preamp, speaker efficiency, and resistor ratios for the law faking pot.. A log or audio taper pot will run into the same considerations and often have lousy tracking between channels (or seperate pots) at one end of the range. They are also not a real log relationship and different brand "log" pots very often have different tapers. There is a much better selection of linear taper pots with better sounding resistive materials.
I can't imagine the rational for your advice unless you heading up a group buy of Noble pots.........
BTW........ I have real question in what qualifies as a group buy that distinguishes at from using the forum as a free outlet for selling stuff. The large quantities seem to separate it from the purpose and restrictions of the Trading Post.
I find very puzzling that two moderators for the forum seem to be the most involved in the group buy efforts. I applaud to efforts to get quantity pricing for the members but see not accounting for what the group buyer is making in profits. A targeted and no advertising cost sale to the "group" seems to be secondary to the considerations of someone floating a group buy proposal to see the size of the customer base up front. We also have people using other peoples group buy as an entry for a very similar product. We also have people well known and regarded who's names, articles,
websites are being used to market Group Buy products. not to mention the links to members commercial websites. The recent incident with the Passlabs exploitation by another diy website seems to have escaped everyone's memory. I still see inappropriate trolling for business in non trading post threads after they were told to stop. When did I miss the point where this become gray area overlap to full blown do whatever you want commercial exploitation of what I thought was supposed to be noncommercial website? If the rules have flown out the window please let me know. Free advertising and a free focus on the group to sell to seem to be too good a deal to pass up if no one minds. There are many members of the forum who commercial interest in audio who very successful avoid these abuses. Then I guess there are who don't want to make the effort and know a free ride when they see one.
"Forget the linear pot, it's curve is not very appropriate for good control range with NI amp."
What are you talking about? This depends on signal levels form the
preamp, speaker efficiency, and resistor ratios for the law faking pot.. A log or audio taper pot will run into the same considerations and often have lousy tracking between channels (or seperate pots) at one end of the range. They are also not a real log relationship and different brand "log" pots very often have different tapers. There is a much better selection of linear taper pots with better sounding resistive materials.
I can't imagine the rational for your advice unless you heading up a group buy of Noble pots.........
BTW........ I have real question in what qualifies as a group buy that distinguishes at from using the forum as a free outlet for selling stuff. The large quantities seem to separate it from the purpose and restrictions of the Trading Post.
I find very puzzling that two moderators for the forum seem to be the most involved in the group buy efforts. I applaud to efforts to get quantity pricing for the members but see not accounting for what the group buyer is making in profits. A targeted and no advertising cost sale to the "group" seems to be secondary to the considerations of someone floating a group buy proposal to see the size of the customer base up front. We also have people using other peoples group buy as an entry for a very similar product. We also have people well known and regarded who's names, articles,
websites are being used to market Group Buy products. not to mention the links to members commercial websites. The recent incident with the Passlabs exploitation by another diy website seems to have escaped everyone's memory. I still see inappropriate trolling for business in non trading post threads after they were told to stop. When did I miss the point where this become gray area overlap to full blown do whatever you want commercial exploitation of what I thought was supposed to be noncommercial website? If the rules have flown out the window please let me know. Free advertising and a free focus on the group to sell to seem to be too good a deal to pass up if no one minds. There are many members of the forum who commercial interest in audio who very successful avoid these abuses. Then I guess there are who don't want to make the effort and know a free ride when they see one.
Re: I wouldn't
Obviously you didn't try them both in GC amp. 50k or 100k linear pot has very poor control range and is not appropriate. I'm not talking about law faking setups, as I never tried it myself. You might find lousy tracking on cheap pots, but all the better ones are not any worse in this department. I'm curious why you didn't use linear pot in HH passive preamp (if you are such a fan of those) but decided on log Alps?
So what do you think I'm making on Nobel pots? Probably much less than you tried to make on those:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=6158&highlight=
Fred Dieckmann said:
Obviously you didn't try them both in GC amp. 50k or 100k linear pot has very poor control range and is not appropriate. I'm not talking about law faking setups, as I never tried it myself. You might find lousy tracking on cheap pots, but all the better ones are not any worse in this department. I'm curious why you didn't use linear pot in HH passive preamp (if you are such a fan of those) but decided on log Alps?
So what do you think I'm making on Nobel pots? Probably much less than you tried to make on those:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=6158&highlight=
Re: I wouldn't
Can you be more clear on that, as I can't figure out what you are trying to say? This may also qualify as a good entry into funny posts thread.
Fred Dieckmann said:
Can you be more clear on that, as I can't figure out what you are trying to say? This may also qualify as a good entry into funny posts thread.
Much as I find in sets off warning bells when I agree even somewhat with Phred. -especially after he helped clone Pass's crossover, causing Nelson great anxiety.
You aren't supposed to be making anything on your pots if you post outside of the trading post.
fred was posting on the trading post so can profit as much as he likes.
Brian GT is clearly not making money , because we know pretty
much what the components cost. He doesn't have a commercial website. I have encouraged him to make a profit so that he won't lose interest, but keep us supplied with gainkits. He would have to start posting in the Trading Post then.
Peter, you do seem to be starting a business, and at some point I think Fred is right- you've got to go to the Trading Post as the Remote relay volume APOX people did from the start.
You aren't supposed to be making anything on your pots if you post outside of the trading post.
fred was posting on the trading post so can profit as much as he likes.
Brian GT is clearly not making money , because we know pretty
much what the components cost. He doesn't have a commercial website. I have encouraged him to make a profit so that he won't lose interest, but keep us supplied with gainkits. He would have to start posting in the Trading Post then.
Peter, you do seem to be starting a business, and at some point I think Fred is right- you've got to go to the Trading Post as the Remote relay volume APOX people did from the start.
Variac said:
What change will it make? Your peace of mind?
I thought advertising in Trading Post is exploiting forum for commercial purposes, that's why I didn't use it.
The chassis thread is just that, discussing chassis design and answering questions, nothing more. Chassis still belongs to group buy category as profits were not calculated and can't be predicted. This is a new venture and pretty much I might even loose money on that, so a sort of safety margin was considered. Any possible profits will be shared into financing the forum operation, so I think it is more noble cause, and has much more appeal than someone's constant moaning about exploitation contributing nothing to the forum.
I'm reselling Noble pots at the same price I'm getting them from Percy (not even adding my shipping costs). When I hit certain number the price will go down, but I can't be sure that number will be reached, so what's the point questioning that?
- Status
- Not open for further replies.