What is a hot SS chassis?

[maxhifi]

Originally Posted by Jon A.

Some are biased against hot chassis solid-state sets just because, well, they're solid-state. As for hot chassis tube sets, I've never heard a peep against them because of that. It's about preference, not superiority.

You have now! Especially in a tube set, which requires more frequent service, it is nice to know your life is not in jeopardy just by touching the chassis. Cold chassis sets are safer to work on, and don't require a cumbersome isolation trabsformer.

[dieseljeep]

Originally Posted by maxhifi

You have now! Especially in a tube set, which requires more frequent service, it is nice to know your life is not in jeopardy just by touching the chassis. Cold chassis sets are safer to work on, and don't require a cumbersome isolation trabsformer.

I was always biased, toward a transformer power supply, in a vacuum tube set. I always considered it to be a higher quality model.
It seemed funny that Muntz, being one of the lowest priced sets, used full power transformers until around the 1955 model year.

[Jon A.]

Originally Posted by maxhifi

You have now! Especially in a tube set, which requires more frequent service, it is nice to know your life is not in jeopardy just by touching the chassis. Cold chassis sets are safer to work on, and don't require a cumbersome isolation trabsformer.

Normally I wouldn't know if a chassis is hot or cold unless I saw a sticker on it indicating this. Until I get an isolation transformer I suppose I'll just have to reverse plugs if my meter shows voltage between the chassis and ground.

[rrrhre2s]

Another Possibility that the set has a full-wave rectified power supply with 4 diodes in a bridge configuration. Placing the chassis ground at about 70 volts above ground regardless of line cord plug polarity.

rrrhre2s

[rca2000]

MOST often...modern sets that have an SMPS power supply are 'cold" chassis, other than the primary side of the power supply. This has been pretty much the standard since the late 1980's or so--as sets with AV I/O connectors became popular. It IS possible to have AV connectors and such with a hot chassis, BUT it then becomes a big deal , using a bunch of either isolating networks using either transformers or optocouplers for EVERY connector, in or out. With a cold chassis-isolation is not necessary.

Now...there IS a type of SMPS out there...that is NOT isolated,known as the "buck converter", but it is not often used anymore. Zenith did use it on the 9_516 chassis.

Pretty much if you see an SMPS transformer on the chassis in the power supply...thee set IS isolated. Especially if it has multiple AV in/outs .

Also, since SMPS sets tend to be less power hungry than those with a hot linear regulator--most al sets these day are SMPS powered and cold. I have NEVER seen a flat panel with a hot chassis. Hot inverters yes--but chassis NO.

Now--Sony did NOT often use a cold chassis, into the mid-1990's or so--it was common to see a hot chassis with a bunch of isolation networks on the AV board, often ceramic-covered..But finally--they went to cold SMPS supplies...done the "Sony way"..with difficult to keep repaired ckty that was VERY finicky and delicate.

I have always been partial to cold chassis...and ALWAYS will be. Be it a tv, amp, radio or stereo chassis.