Zv9

[VT67]

To what extend can we deviate from the given values of some parts? For example; R1 through R6 are 2 Ohm 3Watt types, RS has 3W Metal Oxide resistors but they are 2R2. C8 is 20 pF, I have Silver Mica’s but with a value of 22 pF.

Regards

 

[jh6you]

C8 is 20 pF, I have Silver Mica’s but with a value of 22 pF.

I think if you measure yours of 22pF, you might find actual value in-beteen 20-24pF . . .

I think that even Nelson Pass has his tolrance . . . guessing at least +/-10%. The product itself often has tolerance of +/-20%.

I do not care +/- 20% tolerance very much. When I have to use a pair, however, I always enjoy measureing them and choose a pair having the same value.

 

[VT67]

Need assistance

Hi guys

I'm going to place an order for some parts that I need to finish this amp. Amongst these parts is the transformer(s) and the PS caps.
What voltage is required for this amp, 50VDC? In that case I will need a dual 40V secondaries tranny (40x1,412=±56VDC). Is this to high?
With a working voltage of 50VDC I will need caps rated for at least 63VDC. I can only find 10000µF/63V from Panasonic type TSHA, are these good enough?

Regards

 

[Rtop84]

Re: Need assistance

Hi guys
Is this to high?
Regards

No, it isn't. Voltage value always will be lower then value from formula and you can use CRC or CLC with some voltage drops,so 40V should be OK.

 

[VT67]

Thanks Rafal.

I just found out that I can have two (for free) 300VA 2x18V trannys.
If I connect the secondaries of each transformer in series I will end up with 36VAC. After rectification (36VACx1.412) I should have a theoretical voltage of ±50VDC. If I take in to acount a voltage drop of 4V (diodes) the DC rails will be in the neighbourhood of ±46VDC. In that case I can use 50V caps. I hope that the amp will work OK with these voltages. (Mr.Pass maybe....)

Regards

 

[R-K Rønningstad]

I think 50 V caps are too close. If your mains for some reason goes up some percents, you may exceed those 50 V. In my opinion use 63 V capacitors.

best
RK

 

[Dennis Hui]

transformer question

Hi guys,

I have a 500VA 39-0-39 transformer (centre-tapped, not
dual secondaries). Is there some way to get two
0-50 rails from this transformer? Would this be done
using two bridge rectifiers, where the centre tap
of the transformer is connected to both bridges?

Another question: How much capacitance per
rail are you using? Do you think 40000uF is
enough?

Thanks,
Dennis

 

[VT67]

I'm thinking to get me two these, it seems like they will do the job.

Regards

 

[paulb]

Re: transformer question

Hi guys,

I have a 500VA 39-0-39 transformer (centre-tapped, not
dual secondaries). Is there some way to get two
0-50 rails from this transformer? Would this be done
using two bridge rectifiers, where the centre tap
of the transformer is connected to both bridges?

Another question: How much capacitance per
rail are you using? Do you think 40000uF is
enough?

Thanks,
Dennis

Use two of these
http://sound.westhost.com/power-supplies.htm#fullwave
connected to the same transformer.
I recommend you read the whole article.

If this is for the ZenV9, yes 40mF is enough. It has a filter on the power supply line.

 

[VT67]

Anyone else started building yet?

Regards

 

[VT67]

Apparently not!!

Regards

 

[jacco vermeulen]

Look friend,
some of us are still waiting for boards to arrive.
(third time your Antwerp mail beat me)

 

[VT67]

OK, now I'm starting to feel guilty.
If it's any consolation, I'm still waiting for some parts.
I do appreciate it that you still cal me "friend".

Regards

 

[flg]

Well, if you really want to know... I cut a board... ended up getting sidelined due to Circlotron work... I don't know if the board is in a box or not... I'm being Dev#$%& and I have to move... So everything is in a Box... But... I have JFETs... I recently started working on a Pspice model... I like doin that first... the jump from the datasheet to the bench is smoother... Trouble is, I don't think anyone is brave enough to say they have the last word in sim models, not even Lovoltech, so, I'm trying to make modify whatever to get there... Looks promissing so far...
Actually, I want to build a ZV9-T type of circuit and that will be 2 1/2s of a ZV9 and a bigA$% Inductor load device...
No I'm not building yet
Thanks for asking

 

[jacco vermeulen]

being Dev#$%&

Sorry to read that. Sounds like Scotsdale will have to wait a bit longer.

 

[VT67]

Amp Progress

Not to annoy any of you, but this is how far I got at the moment.
The big caps (Panasonic TSHA) arived today along with the 3W resistors. Most of the other parts I already had laying around.
Now I'm waiting for the heatsinks and fet's.

Regards

 

[flg]

Scottsdale??? If they were waiting, it was because I bought some real Pass Labs equipment... I'm sure I could live with that...

 

[Paul Ebert]

What are ZV9 builders using for the capacitors? I assume that C6 and C7 should be some fancy film caps. Can C2, C3, C4, C5 and C9 be electrolytics? Would there be an improvement in making them film? Lastly, what kind of cap should C8 be? The only thing I've found that small is a silver mica. Is that OK?

Thanks!

Paul Ebert

 

[jimmyd53]

GEWA,

Which PT's are you using? Source? Thanks.

JAMES

 

[Rtop84]

What are ZV9 builders using for the capacitors? I assume that C6 and C7 should be some fancy film caps. Can C2, C3, C4, C5 and C9 be electrolytics? Would there be an improvement in making them film?

Yes, they can. Perhaps film caps will be better but at 220uF, their size will be enormous . You can use BG N type - they are very very good and they can be compared with film caps. C7 is rather critical part- it sould be HQ film, PIO etc. cap- you can increase its value. C1 should be best quality as you can get electrolyc cap.

Lastly, what kind of cap should C8 be? The only thing I've found that small is a silver mica. Is that OK?
[/B]

Yes it is.It's probably the best caps for this puropse.