F5 Case
Hi guys, has anyone bought one of these cases from Johnny at DIYClub (Hong Kong) ? I am looking at building a stereo bridged F5 (ie. four amps in one case), and I think this dude might be big enough. The heat sinks are aluminum and are 380 mm x 150 mm x 55 mm deep and have ~ 45 fins per side. Just scaling by fin area from a Conrad MF35-151.5 spec., each side should be good for ~ 1.2 degrees C / watt. It has a 1/2 thick milled front face also.
It is a little steep at $ 411.00, but considering the quality of the caseand the size of these sinks, it might be worth it.
See: http://diyclub.biz/catalog/product_info.php?cPath=1_249_154_138&products_id=587
Hi guys, has anyone bought one of these cases from Johnny at DIYClub (Hong Kong) ? I am looking at building a stereo bridged F5 (ie. four amps in one case), and I think this dude might be big enough. The heat sinks are aluminum and are 380 mm x 150 mm x 55 mm deep and have ~ 45 fins per side. Just scaling by fin area from a Conrad MF35-151.5 spec., each side should be good for ~ 1.2 degrees C / watt. It has a 1/2 thick milled front face also.
It is a little steep at $ 411.00, but considering the quality of the caseand the size of these sinks, it might be worth it.
See: http://diyclub.biz/catalog/product_info.php?cPath=1_249_154_138&products_id=587
Old capacitors
In my toob building days I bought a bunch of old photoflash caps at a surplus store for a Brian Clark designed SP-6B clone preamp. Although they were rated at 600V, when I applied 400 VDC to them from a 5AR4 rectifier toob, a couple of them went off like shotgun shells......GRollins is right, use several feet of wire and form them slowly with a Variac. At 50V they won't go off as spectacularly as a photoflash, but they will stink to high heaven and **** off your spouse.
In my toob building days I bought a bunch of old photoflash caps at a surplus store for a Brian Clark designed SP-6B clone preamp. Although they were rated at 600V, when I applied 400 VDC to them from a 5AR4 rectifier toob, a couple of them went off like shotgun shells......GRollins is right, use several feet of wire and form them slowly with a Variac. At 50V they won't go off as spectacularly as a photoflash, but they will stink to high heaven and **** off your spouse.
As far as the aluminum cases go there is a guy by the name of Chan Lawrence that sells on Ebay as biglawhk (lawrencechanbig@msn.com) that has similar products as DIYCLUB for less money. They appear to be some kind of surplus cases and he has a few dozen different variations. The down side is that in order to get them at a decent price they ship regular post instead of airmail. I have a large blk case with heatsinks enroute via a "slow boat from China" that will hopefully be here in the next 30days or so. I plan on posting some pictures if it turns out to be a viable option for the DIY crowd in the future.
Regards, Daniel.
Re: Old capacitors
I've also built a B.Clark preamp, the 4TuBe DynaPAS version altho I did purchase his 6 tube and cross over manuals. Lately I've gone back to the Vorhis Last Pass but using Brians master regulator and buffer regs.
___________________________________________________
Thanks Zen Mod & Bill.
Ichiban
Old tube
tinker'r
ps: Sorry for all the OT
dcbingaman said:
I've also built a B.Clark preamp, the 4TuBe DynaPAS version altho I did purchase his 6 tube and cross over manuals. Lately I've gone back to the Vorhis Last Pass but using Brians master regulator and buffer regs.
___________________________________________________
Thanks Zen Mod & Bill.
Ichiban
Old tube
tinker'r ps: Sorry for all the OT
Power output if F5 bridge/balanced
Do I have this right, 
if the F5 is bridged/balanced the output power will go up x4, 
to be 100w in class A / 200w in class AB ? 
I'm hoping that each Conrad 350x151.5 heat sink {.21c/w * 1.4 = .294 C/W},
with two amps per sink
will squeak by, without a fan.
What say ye?
Do I have this right, if the F5 is bridged/balanced the output power will go up x4, to be 100w in class A / 200w in class AB ? I'm hoping that each Conrad 350x151.5 heat sink {.21c/w * 1.4 = .294 C/W},
with two amps per sink
will squeak by, without a fan.What say ye?
If you bridge two amplifiers, maximum output level goes up but Class A output will remain the same.
100W in Class A is twice the bias level of 25W, twice the Class A bias current requires 2 F5's in parallel. (same same story as the F4)
4 times 60W =240W dissipation for 100W/8 in A, 200W/4 in AB.
100W in Class A is twice the bias level of 25W, twice the Class A bias current requires 2 F5's in parallel. (same same story as the F4)
4 times 60W =240W dissipation for 100W/8 in A, 200W/4 in AB.
