timmyjim

Thump is one thing, but should not be overly loud. I would put a scope on the +/-rails, one set at a time, starting with the highest voltage rails. Do they decay/bleed down at the same rate? They should look about the same, but opposite polarity. Whats likely happening is that the +/-12V decay at much different rates, this causes the input opamp to rail in one direction or the other, creating a large transition at the output. Since the +/-12V are derived from the higher voltage rails, it's likely that one of them is the culprit.

I think the best option for home use is a quiet computer fan. You would need to change out the resistors on the fan board to accommodate the higher impedance of the new fan. The amp vents by pulling air from front to back. This post uses a 80mm computer fan. Note that it's just a bit too large and needed to be sanded down a bit.

Not sure how you are measuring this? Assuming an accurate measurement, it's still too high. Unless you have disabled some of the "speaker protection" circuitry, this must have been a very short test? Carver added circuitry to the m1.5t that seems more marketing driven than anything else. It will put the amp into protection after a short time at rated power. This circuitry can be disabled by lifting 2 diodes on the main board. You can figure this out easily by comparing the pm1.5 and m1.5t main board schematics. With these diodes removed, the m1.5t becomes a 450WPC@8ohm amplifier .... no other modification required.

A lot of Carver amps have hot spots. Fairly normal. The m1.5t does get hot right in the middle. .... iirc the intersection of the back amp card and the main board. Impressive.

Properly adjusted, the m1.5t does idle a bit higher than most of the other amps, but it should be under 500mA as is specified in most service manuals. Should be in the 400-450mA ballpark. The service manual indicates that you should adjust bias across R87 to 4mV as you have done. I have not worked on a m1.5t in a while, but I don't believe this is accurate. I always adjusted bias across BOTH emitter resistors, in fact always connected my meter to the emitters, not the resistors. Easier. As a sanity check, I reviewed the pm1.5 manual to see if it suggests the same bias adjust. In fact it indicates as I have mentioned above, connecting the meter across BOTH R49 and R87. It also suggests a level of 3.4mV. This is the method you should use. I think your amp will be fine and indicate less than 500mA of idle current when adjusted this way. I might suggest that you use the pm1.5 schematics for any future amp card debug. They are easier to read, and match about 99%.

If you have 5.1V between TP3 and TP4 ....... your amp is on fire.

Iv'e used these in the past, very strong, a bit pricey: https://www.parts-express.com/Neodymium-Disc-Magnet-3-8-x-3-16-320-016?quantity=1 They used to sell in a set of 4, but now seems to be individual.

I'll skip the part where "if you don't have something nice to say, don't say anything". These amps are VERY difficult to work on, both electrically and mechanically. The power supply is unlike any other Carver amp. I mostly enjoy debug and repair, not this one. If you look at the PM2.0t manual, there is a description of bringing up the power supply with a variac external variable supply. I'm not going to go back and look at it as I might start to convulse, but there is something. (I went back, see previous correction) Ay any rate, you will find yourself removing many tiny screws to get at the necessary test points. You will end up with thermal paste all over the place. The Darlington transistors in the PS section are difficult to source, as is the PWM IC. If the power supply proves to be OK, then you probably have a chance at repair (I guess I did have a positive). Good Luck.

I wish Guttenberg had something interesting to say in any of his posts. It's all a bunch of him "lip smacking" and telling you how wonderful everything is. Where are the negative reviews? They don't exist. You don't need to actually watch anything he produces. Just look at the YouTube post title which includes the product name. If he "reviewed" it, you already know he thinks it's the greatest thing since sliced bread. No need to watch. A bunch of years ago he reviewed a speaker that I happened to own. He told me how wonderful it was. Personally, I wanted to pour gasoline on them and burn them in my backyard.

Joe Bonamassa - Just Got Paid

Robert Randolph - Nobody Soul

It seems that JBL in particular has wrestled with this for some time. Follow this link and download the Polarity Conventions tech note. It doesn't apply directly to your models, but it does indicate that they couldn't make up their mind to the point they had to write a tech note ..... https://jblpro.com/en/products/4312a

Tedeschi Trucks Band. Anyhow. How many musicians can you pack in a studio recording? Many.

Pixies - Gouge Away

Bryan Ferry Like a Hurricane cover.