Chassis Layout Advice

Mosquito · 23rd November 2009, 02:03 PM

Hi everybody!
Well, I think that I'm definitely a medium / low watt Push-Pull supporter. Really deeeply like all those amps like El Cheapo, Baby Huey, RLD, Frankenhouse and the genre.
Even if maybe in the future I'll able to put together one of my own design, sure it will be of a similar topology.
So I'm thinking about to develop some kind of standard chassis and layout that can accomodate this type of amplifier.
The picture shows a very preliminar effort, but I'd like some advise, letting aside the asthetics, in regard the convenience of the showed phisical disposition of parts.
Many tanks
JJT

Mosquito · 23rd November 2009, 04:09 PM

Ahemm, I'm very sorry for the typo at TD title, gentlemen.., maybe some gentle moderator can fix it..

pointy · 23rd November 2009, 08:09 PM

with a chassis like that i would go for a radford tea trolley type set up.

with the power transformer and choke under a mesh box in the middle and each channel on either side.

but you would need to find space for the gz/ez tube if you use one.

m6tt · 23rd November 2009, 08:41 PM

Generally it's best to have the power magnetics as far from the signal magnetics as possible. I can't really tell if you've done that there, but I'd do something like power magnetics (shared) in the center, with OPTs and other signal magnetics on the edges with the tubes in between. That being said, it looks like the rotation of the transformers *should* prevent coupling. I believe it is somewhat transformer dependent as to how close they can get before coupling. Pointy's steel mesh shield sounds like a good idea, but I am not familiar with the aformentioned tea trolley

! I know we like to see our tubes, but taking a hint from RF equipment, I am surprised more high quality amps don't have preamps, power stages, and magnetics in closed, divided steel compartments.

Mosquito · 23rd November 2009, 09:14 PM

Thanks for the opinions, very much apreciated. As for the tea trolley, I suspect is some Brit thing used as image of how was the layout of some Ratford amp . I'll Goggle "Ratford" pictures to give me an idea.
Thanks again.
JJT

Cassiel · 23rd November 2009, 10:18 PM

I really like the color of your power trafo. Did you paint it? and if you did can you tell me the name of that grey?

Mosquito · 11:05 PM

Yes, it's painted with aluminium primer, cause I don'like the original glossy finished metal bells.
I'll finish the OPTs same way.The product is a german made coat.
Duplicolor
Motip Dupli GmbH
Hassmersheim
product code 557255
If you are based in Madrid, you'll found it at Leroy Merlin stores.

PD: Pointy, I'm sorry it seems that I'm not in one of my smart days, of course the name is "Radford" not Ratford..

Cassiel · 23rd November 2009, 10:58 PM

Thanks!

Molloy · 25th November 2009, 01:09 AM

The amp would look better if the two OT are facing the same direction. Don´t expect hum problems because of this.

chrish · 25th November 2009, 06:39 AM

Morgan Jones gives good advice on this in "Building Valve Amplifiers". In summary, I believe what he says is that you try to keep the small signals away from the big currents and magnetic fields. To that end your amp would be (from front to back) small signal tubes, output tubes, output transformers, rectifier tube and then the power transformer and choke at the back of the chassis. The way you have it laid out now, you are going to have to have high voltage lines going from your power supply past your input tubes to the output transformers.

Layout is more than just the interaction of the magnetics. Think about the voltage and current of all the wiring and how it will interact with the signal.

Also, don't forget about the heater wiring - tightly twisted right up to the sockets and tucked in to the chassis corners etc.

Regards,

Chris

23rd November 2009, 10:44 PM	#7
Mosquito diyAudio Member Join Date: Sep 2009 Location: Santa Fe, Argentina	Yes, it's painted with aluminium primer, cause I don'like the original glossy finished metal bells. I'll finish the OPTs same way.The product is a german made coat. Duplicolor Motip Dupli GmbH Hassmersheim product code 557255 If you are based in Madrid, you'll found it at Leroy Merlin stores. PD: Pointy, I'm sorry it seems that I'm not in one of my smart days, of course the name is "Radford" not Ratford.. Last edited by Mosquito; 23rd November 2009 at 11:05 PM.

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Need help with chassis layout	bluegti	Chip Amps	2	21st December 2008 01:32 AM
Chassis layout?	Psychobiker	Tubes / Valves	0	12th March 2008 11:12 AM
Chassis layout help	Evenharmonics	Tubes / Valves	4	3rd March 2008 11:52 PM
Chassis Layout & PS questions	Valvomaniac	Tubes / Valves	3	11th April 2007 07:46 AM
help with chassis layout	jarthel	Tubes / Valves	5	27th June 2006 04:41 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read

23rd November 2009, 04:09 PM	#2
Mosquito diyAudio Member Join Date: Sep 2009 Location: Santa Fe, Argentina	Ahemm, I'm very sorry for the typo at TD title, gentlemen.., maybe some gentle moderator can fix it..

23rd November 2009, 08:09 PM	#3
pointy diyAudio Member Join Date: Mar 2009	with a chassis like that i would go for a radford tea trolley type set up. with the power transformer and choke under a mesh box in the middle and each channel on either side. but you would need to find space for the gz/ez tube if you use one.

23rd November 2009, 08:41 PM	#4
m6tt diyAudio Member Join Date: Aug 2007	Generally it's best to have the power magnetics as far from the signal magnetics as possible. I can't really tell if you've done that there, but I'd do something like power magnetics (shared) in the center, with OPTs and other signal magnetics on the edges with the tubes in between. That being said, it looks like the rotation of the transformers should prevent coupling. I believe it is somewhat transformer dependent as to how close they can get before coupling. Pointy's steel mesh shield sounds like a good idea, but I am not familiar with the aformentioned tea trolley ! I know we like to see our tubes, but taking a hint from RF equipment, I am surprised more high quality amps don't have preamps, power stages, and magnetics in closed, divided steel compartments.

23rd November 2009, 09:14 PM	#5
Mosquito diyAudio Member Join Date: Sep 2009 Location: Santa Fe, Argentina	Thanks for the opinions, very much apreciated. As for the tea trolley, I suspect is some Brit thing used as image of how was the layout of some Ratford amp . I'll Goggle "Ratford" pictures to give me an idea. Thanks again. JJT

23rd November 2009, 10:18 PM	#6
Cassiel diyAudio Member Join Date: Sep 2004 Location: Madrid	I really like the color of your power trafo. Did you paint it? and if you did can you tell me the name of that grey?

23rd November 2009, 10:58 PM	#8
Cassiel diyAudio Member Join Date: Sep 2004 Location: Madrid	Thanks!

25th November 2009, 01:09 AM	#9
Molloy Account Disabled Join Date: Aug 2006	The amp would look better if the two OT are facing the same direction. Don´t expect hum problems because of this.

25th November 2009, 06:39 AM	#10
chrish diyAudio Member Join Date: Oct 2003 Location: Sydney	Morgan Jones gives good advice on this in "Building Valve Amplifiers". In summary, I believe what he says is that you try to keep the small signals away from the big currents and magnetic fields. To that end your amp would be (from front to back) small signal tubes, output tubes, output transformers, rectifier tube and then the power transformer and choke at the back of the chassis. The way you have it laid out now, you are going to have to have high voltage lines going from your power supply past your input tubes to the output transformers. Layout is more than just the interaction of the magnetics. Think about the voltage and current of all the wiring and how it will interact with the signal. Also, don't forget about the heater wiring - tightly twisted right up to the sockets and tucked in to the chassis corners etc. Regards, Chris

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)