Hi,
I am in the process of building my first Pass DIY amp. I have searched the listings for answers to many of the questions that I have with varying levels of success. So i thought i would start a post where i might be able to ask specific questions regarding "a beginners guide to the ZV9" and as other people build their ZV9 they might add questions to this post... an informal wiki.
1. My first questions relates to capacitor C7 as labelled on Veterans boards. I would like to use either a Kimber 1uf or Solen 1uf cap. The Kimber's are polarized. How would i determine the correct orientation. It appears that they run in parallel to the 10,000uF cap. If this is the case do i attach the +ve leg of the 10,000uf cap to the +ve leg of the Kimber?
2. Star grounding: Do i star ground from the PCB ground, output ground and rectifier ground all to the chassis. If this is the case and i am using 400v 35A GBPC rect. bridge, where would i star ground on this as there are only tags for live and neutral?
3. Would a 3amp slow blow fuse work with this project?
4. Has anyone used Artic Silver 5 Polysynthetic Thermal Compound to attached JFET's to heatsinks iinstead of mechanical screws. It seems like a good solution and is used extensivley in the computer industry.
Thanks
Neil
I am in the process of building my first Pass DIY amp. I have searched the listings for answers to many of the questions that I have with varying levels of success. So i thought i would start a post where i might be able to ask specific questions regarding "a beginners guide to the ZV9" and as other people build their ZV9 they might add questions to this post... an informal wiki.
1. My first questions relates to capacitor C7 as labelled on Veterans boards. I would like to use either a Kimber 1uf or Solen 1uf cap. The Kimber's are polarized. How would i determine the correct orientation. It appears that they run in parallel to the 10,000uF cap. If this is the case do i attach the +ve leg of the 10,000uf cap to the +ve leg of the Kimber?
2. Star grounding: Do i star ground from the PCB ground, output ground and rectifier ground all to the chassis. If this is the case and i am using 400v 35A GBPC rect. bridge, where would i star ground on this as there are only tags for live and neutral?
3. Would a 3amp slow blow fuse work with this project?
4. Has anyone used Artic Silver 5 Polysynthetic Thermal Compound to attached JFET's to heatsinks iinstead of mechanical screws. It seems like a good solution and is used extensivley in the computer industry.
Thanks
Neil
neil_kaye said:
1. yes-same polarization as main (10KuF) cap
2. make your star ground on filter cap,wire all grounds independently to this point,and connect chassis to it via thermistor
3.depending what size of xformer and main cap bank you intent to use
4. old ways,good ways........mebbe one day you'll must change that part ,from any reason.......computer industry is more "use it ,throw it if doesn't work anymore"
Re: Re: Re: Help a noob build a ZV9
1. filter cap is your main bank
2.you can try with mentioned fuse,but I have some doubts that you'll need bigger one
thermistor..........resistor with (in this case) negative temp. coefficient.....with current ,resistance decreases.........just chill out some time and read those Pass's manuals little more .......
neil_kaye said:
1. filter cap is your main bank
2.you can try with mentioned fuse,but I have some doubts that you'll need bigger one
thermistor..........resistor with (in this case) negative temp. coefficient.....with current ,resistance decreases.........just chill out some time and read those Pass's manuals little more .......
Re: Re: Re: Help a noob build a ZV9
Hi Neil,
a thermistor is a special resistor that offers a resistance when it is cold. When it becomes hot, after a few seconds, resistance drops near to zero. It is used here as inrush current limiter: what make fuse blow at startup.
I got two Digikey p.n. 570-1032-ND: current limiter inrush 10ohm 5A
The problem is where to place them.
I would put the two thermistors before the transformer, between live and safety gnd, and between neutral and gnd, respectively.
But Zen Mod says to put one between chassis and star ground. It's not clear to me how does it works.
Ciao
P.S.
The star ground point mentioned by Zen Mod is the negative pole of the first 10000uF capacitor of the PS pcb. As we both use Veteran's boards, we have two PS boards. So I would better have the star ground point on the chassis, between the two PS, and connect there filter caps grounds, safety ground, input and output signal grounds.
neil_kaye said:
Hi Neil,
a thermistor is a special resistor that offers a resistance when it is cold. When it becomes hot, after a few seconds, resistance drops near to zero. It is used here as inrush current limiter: what make fuse blow at startup.
I got two Digikey p.n. 570-1032-ND: current limiter inrush 10ohm 5A
An externally hosted image should be here but it was not working when we last tested it.
The problem is where to place them.
I would put the two thermistors before the transformer, between live and safety gnd, and between neutral and gnd, respectively.
But Zen Mod says to put one between chassis and star ground. It's not clear to me how does it works.
Ciao
P.S.
The star ground point mentioned by Zen Mod is the negative pole of the first 10000uF capacitor of the PS pcb. As we both use Veteran's boards, we have two PS boards. So I would better have the star ground point on the chassis, between the two PS, and connect there filter caps grounds, safety ground, input and output signal grounds.
Hi Neil,
You may also want to have a look at Figure 6 of the
ZV4 article ( http://www.passdiy.com/pdf/zen-v4.pdf )
It shows the use of a thermistor and diode bridge
for softstart and groundloop isolation purposes in an
unregulated power supply which is also suitable
for the ZV9.
Cheers,
Dennis
You may also want to have a look at Figure 6 of the
ZV4 article ( http://www.passdiy.com/pdf/zen-v4.pdf )
It shows the use of a thermistor and diode bridge
for softstart and groundloop isolation purposes in an
unregulated power supply which is also suitable
for the ZV9.
Cheers,
Dennis
Hey Neil,
Since you asked for help, i would recommend building the original Zen amp first. It's a well documented project, and your chances of finishing it with a working amp are high.
Sure, the ZV9 is a more refined amp, and probably even sounds better than the original Zen. But the Zen amp is a great learning experience.
If i can't talk you in to building it, at least read all the Zen articles leading up to the ZV9. Good luck and have fun
(and buy big heat sinks)
Since you asked for help, i would recommend building the original Zen amp first. It's a well documented project, and your chances of finishing it with a working amp are high.
Sure, the ZV9 is a more refined amp, and probably even sounds better than the original Zen. But the Zen amp is a great learning experience.
If i can't talk you in to building it, at least read all the Zen articles leading up to the ZV9. Good luck and have fun
(and buy big heat sinks)
Thomas, that does not sound as a good idea, if I understand you correctly. If you use the Thermistor as an inrush current limiter, you must put 1 Thermistor in series with the hot (live) lead. I usually solder the thermistor directly to the hot leg on the AC-inlet socket. Dont ground the hot lead through a termistor, which will be as good as a short
Nothing wrong with connecting the circuit GND to chassis ground through a Thermistor though
Steen
All this help is really fantastic. I will put together a wiring diagram in the next few days after i peice this altogther and perhaps then soemone would be kind enought to look it over.
In the meantime, i am building a VU meter and was wondering where i should connect the circuit to the amp in terms of the risk of adding noise:
1. Low input at the line level in or/
2. High output at the speaker out.
Thanks
In the meantime, i am building a VU meter and was wondering where i should connect the circuit to the amp in terms of the risk of adding noise:
1. Low input at the line level in or/
2. High output at the speaker out.
Thanks
Re: Re: Help a noob build a ZV9
Let me make a suggestion here:
It is difficult to get a real star ground on the filter cap because
there is so much charging current flying through the cap's
terminal. Try running a fat, short piece of wire from the filter cap
ground to a star ground.
Zen Mod said:
Let me make a suggestion here:
It is difficult to get a real star ground on the filter cap because
there is so much charging current flying through the cap's
terminal. Try running a fat, short piece of wire from the filter cap
ground to a star ground.
Re: Re: Re: Help a noob build a ZV9
I know that you know.........
little copper or Al plate screwed (schraubed) to cap is usual way for that........
off topic.........I didn't receive yay or ney regarding Babelfish pcb related mail
in disgrace again ?
Nelson Pass said:
Let me make a suggestion here:
It is difficult to get a real star ground on the filter cap because
there is so much charging current flying through the cap's
terminal. Try running a fat, short piece of wire from the filter cap
ground to a star ground.
I know that you know.........
little copper or Al plate screwed (schraubed) to cap is usual way for that........
off topic.........I didn't receive yay or ney regarding Babelfish pcb related mail
in disgrace again ?
Re: Re: Re: Re: Re: Help a noob build a ZV9
hehe
like we said locally (on Serbian)........Sala mala (pronouncing as "shala mala")
which means "little joke" or ,if I understand it correctly " just teasin' ya"
just one more question (just to be consistent with my profile ) :
how many stages you numbered in MA24?
no further comments ........expected
Nelson Pass said:
When were you ever in disgrace?
hehe
like we said locally (on Serbian)........Sala mala (pronouncing as "shala mala")
which means "little joke" or ,if I understand it correctly " just teasin' ya"
just one more question (just to be consistent with my profile
) :how many stages you numbered in MA24?
no further comments ........expected
Neil,
Watching your progress with interest. If you have a digital camera please posts some pics as you get close to assembled.
As to the Arctic Silver, I havent used it for anything but computer use. However, I'd be inclined to try it based on CPU use experience. It needs to be applied PAPER thin(try to get practically to translucent) or it will not perform as well as much cheaper alternatives.
Watching your progress with interest. If you have a digital camera please posts some pics as you get close to assembled.
As to the Arctic Silver, I havent used it for anything but computer use. However, I'd be inclined to try it based on CPU use experience. It needs to be applied PAPER thin(try to get practically to translucent) or it will not perform as well as much cheaper alternatives.
This is about as far as i have gotten:
1. Boards are stuffed
2. Heatsinks and toroids ordered. I hope to cut the heatsinks into usuable lengths this week.
In anticipation of putting it all together, i have prepared a skecth of the proposed wiring (Toroid to rectifier to PSU to AMP and all to star ground).
I would be great to get some feedback and suggestions.
Thanks
Neil
1. Boards are stuffed
2. Heatsinks and toroids ordered. I hope to cut the heatsinks into usuable lengths this week.
In anticipation of putting it all together, i have prepared a skecth of the proposed wiring (Toroid to rectifier to PSU to AMP and all to star ground).
I would be great to get some feedback and suggestions.
Thanks
Neil
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