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View Full Version : Got some big old CV A400s on the way.



audiomagnate
03-04-2011, 10:35 PM
I'm looking forward to getting these beasties fired up.I'm getting a pair, so I'll using them for bi-amping.

clmrt
03-05-2011, 07:02 AM
What are they? Any info out there?

stephane RAME
03-05-2011, 08:45 AM
Cerwin Vega A400

Stéphane

hjames
03-05-2011, 09:02 AM
Cerwin Vega A400

Stéphane

I googled it and found an image and a quote
from Grumpy at AK:
This is one BIG Ole Ugly amp. Weights about 50 pounds. Dates from late 70's-early 80's.
Rated at something like 200 wpc into 8 and I guess at least 300 @4. Ain't the prettiest amp around but it was built for power not beauty.

50275

clmrt
03-05-2011, 09:28 AM
I'm lazy, yes.

Cool with the contrasting handles. I like.

Nudies would be cool...

audiomagnate
03-05-2011, 10:39 AM
The ones I'm buying look way better than that. I actually found a service manual on line with Bing with some nice nudies and full specs. Here are some juicy details:

225 wpc into 8 ohms, 350 into 4 ohms, 45 lbs, THD and IM from 1.4 watt to full power .03%

Very sophisticated and effective protection circuitry for its time. Not bridgeable with a switch unfortunately. Fan cooled.

http://www.acousticpsychos.com/Files/Cerwin-Vega/Cerwin-Vega-A-400-pwr-sm.pdf

I'll post better pics and more info on Wednesday after they get here.

audiomagnate
03-10-2011, 07:54 PM
As requested:

audiomagnate
03-15-2011, 09:20 PM
I got one of them to work off and on and it sounds excellent!

audiomagnate
03-26-2011, 10:33 AM
This fan is way too noisy. Any suggestions for a replacement?

grumpy
03-26-2011, 11:19 AM
It appears (looking at the perforated tops/bottoms and plentiful heatsinks on the
driver transistors) that the design is expecting airflow just to keep the insides alive
(as opposed to the output stage transistors which are relying on convection cooling
from the large/side heatsinks). This one looks like it -needs- a fan. Maybe a less
aggressive cfm fan would be sufficient in a home environment (assuming the surrounding
area is kept clear). A measure of heatsink temp vs airflow would be better than my
guessing.

That said, I'd be uncomfortable recommending anything drastic, like just disconnecting
the fan (which -can- work on some pro designs where the insides aren't particularly
well ventilated to begin with and the fan mainly cools the output transistor heat sinks).

Is the Rotron fan just worn out (they can get noisier with age)? There are about 100
models from various manufacturers that would fit. Your's is set up to run from the
AC line voltage, so that's one limit. MX2A3 airflow spec is 105cfm. 47.6dBA noise...

If this one fits and the airflow can be reduced by 50%, Pabst it's a good brand
and quieter replacement for the Rotron/Comair unit:

http://www.newark.com/ebm-papst/4800z/axial-fan-119mm-115vac/dp/86K9866

Yes, good fans are not cheap but cheaper does exist:

http://www.newark.com/nmb-techologies/4715ms-12t-b10-a00/axial-fan-119mm-115vac-90ma/dp/52M1831

as do cheaper direct (similar noise and airflow specs) replacement type units.

Newark has a nice way to drill down using required specs for a part.

audiomagnate
01-13-2012, 10:36 PM
The fan quieted up after a few days of use. It's still running fine. Now I need to get the second one working, which had a majorly toasted protection board, but seems to be intact otherwise. I'm using the functioning one on my rears in a 4.0 setup.