Questions Re Lady Day

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Questions Re Lady Day

Postby RofOZ » Wed May 13, 2009 12:23 pm

Hi,

I bought the Lady Day 3 kit a year ago and finally have got around to putting it together. I live in Australia. I could disassemble the chassis before putting the amps together. Before assembling I would like to ask the following:

    1. I note that the top cover has no vents in it. Does the Lady Day get hot inside? Are there reliability issues particularly with hot capacitors?

    2. The large capacitors in the chassis have no mounts. Is it the intent that they sit upon the bottom cover? Or should they be mounted with cable ties and anchors, or double sided foam tape?

Thanks

Richard
RofOZ
 
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Re: Questions Re Lady Day

Postby brian » Wed May 20, 2009 10:14 am

RofOZ wrote:1. I note that the top cover has no vents in it. Does the Lady Day get hot inside? Are there reliability issues particularly with hot capacitors?

2. The large capacitors in the chassis have no mounts. Is it the intent that they sit upon the bottom cover? Or should they be mounted with cable ties and anchors, or double sided foam tape?


1. No such issues. The tube sockets on on subplates and teh bottom is vented so should be enough airflow unless put in an enclosed cabinet.

2. large caps: easiest is to use RTF silicone made for mounting components.

Brian
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Re: Questions Re Lady Day

Postby RofOZ » Wed May 20, 2009 11:59 am

Hi Brian,

Thanks for the reply.

Regarding the caps - understood.

Regarding the venting - my valve sockets are mounted onto plates that are then mounted onto the thick aluminum top cover. There is no air gap between the sockets and the plates or the plates and the top cover. Everything I have read about valve amps and their caps suggests cooling is a potential issue. This is more so where ambient temperatures can be high. So all the suggestions I have seen include vents in the top cover. This includes externally mounted valves.

1. Was it intended that the mounting plates be raised or lowered relative to the top cover thereby forming a vent - say by a small nut or a few washers?
2. Alternatively, have you found that there is enough convection/conduction within and through chassis to prevent too warm temperatures due to the (estimated) at least 15 to 20 W dissipation due to cathode resistors and power supplies?
3. Here we have nominal 240v mains but it seems my transformer is wired for 230v. Our power might tend on the high side. Have you found that the LD is better run a little under than over regarding mains voltage?

Glad to hear the cooking caps has not been a problem to date with the LD.

Finally, I have completed the Django without remote control. Only had a few hours on the clock and possibly not in an ideal situation. I inserted it between my CD player and auxiliary input (previously CD went direct to auxiliary input) and turned the main amp pot volume control to max. Result: very, very clean transparent sound. I and others have fallen into the trap of playing too loud initially as the ear is used to a level of "noise" so to get that same level of "noise" the volume goes up. I had a similar experience with Lowther speakers and after a couple of hours realised that I my ears were ringing (not for long thankfully). Once the volume is down on a A v B test (highly subjective but so what) the result is simple: the Django stays in place for CD play back. :D

Thanks

Richard
RofOZ
 
Posts: 8
Joined: Fri Nov 07, 2008 8:19 am

Re: Questions Re Lady Day

Postby RofOZ » Sun Jun 07, 2009 7:31 am

Hi Brian,

I guess you must be busy.

I have looked again at the valve socket mounting and due to the nice close fit of the sockets and the top cover there is no space for airflow. Whilst I appreciate your advice that inside chassis temperature is not a problem if cooling vents in the top cover are desired I think they must be drilled. Here in Australia we get 40+ degree C days and my listening room is not as yet air conditioned.

Question: for Australian use have you found it best to run the LD on 230Vac power TX wiring instead of 240Vac wiring? This would rise the HT.

If I elect to drill some holes in the top cover I will have to remove the transformers so at that stage will rewire the power TX connection. 240 or 230V?

Finally, please understand that I see DIY as just that - hobbiest getting on and doing their own thing. I also appreciate that you are not supplying products for Australia per se. So if my questions have caused offense please understand I did not intend any and sorry. So far I have found your company great to deal with and supplying good products to this relatively small market. Please keep it up.

Cheers

Richard
RofOZ
 
Posts: 8
Joined: Fri Nov 07, 2008 8:19 am

Re: Questions Re Lady Day

Postby brian » Mon Jun 08, 2009 7:05 am

Richard
Apologies. I missed it.
Chassis cooling: There isn't much to produce heat in the chassis except the cathode resistor. With the holes in the bottom pan there is easily enough venting to handle it. The aluminuim chassis is surprising effective at dissipating heat and most of the heat is top side. The top plate is meant to be warm as it does it's job but most of the heat it collects come from tubes and transformers -- all top side. As long as there is good airflow around the chassis it should be OK. If you fee l the need for more, you could just mount the sub plates on 5mm standoffs and you'd get a nice 'chimney' effect.
Australia: definitely 240v as some customers there have reported to us as high as 250v at times.
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Re: Questions Re Lady Day

Postby RofOZ » Tue Jun 09, 2009 2:42 am

Thanks Brian.

I will get on with getting the LD's singing.

Cheers

Richard
RofOZ
 
Posts: 8
Joined: Fri Nov 07, 2008 8:19 am


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