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New ampeg speculation - A true B15 Reissue?

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#723
Tronographic said:
The new latches look nice except for the ugly black finish.

Why is everybody so excited about the black diamond tolex and black grillcloth? So boring.

Black is only beautiful on people... ;) which I guess is really brown anyway... Now that's an idea... BROWN DIAMOND!
Click to expand...

I, for one, happen to think the new Black Diamond is nicer looking than the Blue Diamond of old. But you know what they say, "opinions are like a$$ holes, everybody's got one and they all stink".
 
#724
Classickbass said:
I, for one, happen to think the new Black Diamond is nicer looking than the Blue Diamond of old.
Click to expand...
+1

I will admit to some initial skepticism about the Black Diamond instead of the Blue. However, after seeing it I feel like it makes for a very classy looking cabinet (IMHO). I'm still having trouble going there but I'm afraid that if I'm honest with myself I would have to admit that I now actually prefer it over the blue.

Also, color debate aside (I think they look nice), the finish on the new latches seems to be very high quality and has a good feel to it. I think it's powder coat but I don't know for sure.
 
#725
Tronographic said:
The new latches look nice except for the ugly black finish.

Why is everybody so excited about the black diamond tolex and black grillcloth? So boring.

Black is only beautiful on people... ;) which I guess is really brown anyway... Now that's an idea... BROWN DIAMOND!
Click to expand...

In light of not getting Navy Random Flair, I think the Black Diamond is a great choice considering Ampeg has a history of some strange and flashy cosmetics/coverings, especially from the 50's and early 60's.

About a year ago I had found a black shower curtain at Walmart with the "Ampeg" Diamond Check pattern, and thought it would make good material to make a slip cover out of for my B-15. Hard to see in the pic but the pattern impression is dead on to the Blue Check.

blackcheck001.jpg
 
#726
Tronographic said:
The new latches look nice except for the ugly black finish.

Why is everybody so excited about the black diamond tolex and black grillcloth? So boring.

Black is only beautiful on people... ;) which I guess is really brown anyway... Now that's an idea... BROWN DIAMOND!
Click to expand...
they had to do something to differentiate it from the old b-15's. short of printing up a mill run of costly navy random flair, i think black is the next best thing. beats lime green or pink ;)
 
#732
Ric Vice said:
Since I own a B15 NC I noticed that the Hum Ballance Screw is missing from the new amplifier. I guess with a three prong A. C. plug they don't really need it. The nice thing about that control was it the outlet wasn't grounded properly you could remendy the problem.


Ric
Click to expand...

Ampeg mentioned before it's not a re-issue. Maybe they are now running DC on the filaments? Squeeze out the extra db of noise floor.
 
#733
JimmyM said:
does the choke that's in the new circuit take the place of the hum balance control?
Click to expand...

Jimmy - since you asked, you're not allowed to glaze over while reading this.

A choke is an inductor that is sometimes used to smooth the ripple in the high voltage (B+) power supply. Using one makes the amp hum less. Using a choke allows you to smooth the ripple without dropping as much voltage as other smoothing approaches such as a capacitor and resistor would.

One has to be careful with power supply filtering. Too much and the amp can sound sterile and loose touch responsiveness.

The hum balance control is for something else. It is located in the AC heater circuit. Adjusting the pot allows you to balance the overall resistance between each leg of the heater circuit. Normally the pot would be set in the centre and the circuit is balanced. In the past, a balance pot was normally found in hi-fi amps where minimizing hum was very important. It is not really needed in musical instrument amps.

There are two options if you don't have a balance pot. One or the other is used. One option is to have a centre tap (a third wire) on your power transformer heater winding. The other option is to create what is called an artificial centre tap. This is done by connecting a resistor to each leg on the heater winding and then connecting the resistors in series. The series connection point is what is called the artificial centre tap. Which ever type of tap is used, it is either connected to ground or a DC offset voltage (which can help by reducing noise). The artificial centre tap is exactly the same as the hum balance pot set in the middle. The advantage of the hum pot is that you can fine tune the balance to minimize the hum.
 
#734
when i'm arguing about dumb stuff and i'm trying to win, my eyes glaze over. stuff like this i try to absorb ;)

thx for the explanation. i knew they were both to reduce noise so i mistakenly thought they might be related. won't know unless you ask, though.
 
#735
The other "noise solver" that no longer exists is what I like to call the switch of death.

AKA the "Ground Switch" or "Polarity Switch".

It switched one side or the other of the non-polarized incoming AC to ground through a capacitor.

Only problem is when the capacitor fails by shorting out, then you flip the switch to the position that connects the hot side up. Now you've got the chassis floating at line voltage, and there ain't no safety ground to save you.
 
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