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Bugera all tube head

#82
seamonkey said:
You are just guessing here. I would guess that B* is a large scale manufacturer and has first pick at the high quailty parts. Every tube sellers talks about how the measure and only keep and sell the top 10% of the tubes or parts they get. First in line gets the best parts. B* being larger than LOUD is probably getting first pick.



Again - speculation on your part. B* invests a big in automation - check the videos on Behringer city.



Again speculation your opinions - you can have them, I do, And I see they do have QC. Check the videos. They actually play through every amp before it leaves the plant. I've taken B* stuff apart and say for the price they use the same components gear selling 2 to 3x as much uses.



Ha - no - check their offerings they had 50 new products of their own design at NAMM. Try to copy one and they will sue your *ss off.

Sure they copied SVT for this Bugera. But who cares about some 60's technology. These guys comparing car engines here - look at car engines in the 60's - not of lot of IP that has anything to do with today's car engines.

B* looked inside a SVT and figure out a way to make them just as good but cheaper. You'll see - they will be big sellers. And they'll be just as reliable as you could expect from any tube amp. They will be a big seller in this niche market.
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Yes, I am speculating, obviously. You seem to have put in more research than I have into the hows and whys of b*, so cool, i won't argue with anything you're backing up with evidence. My proposed theories are based on extensive reports of on-the-gig failures and the fact that 2 of the 3 behringer products i've used have done just that, while the only other product I've EVER had die on a gig was a cable (after years of wear and tear). But out of curiosity, what's your theory on how and why their products are so much cheaper than their competitors, if not because they cut costs somewhere? Just because they're a large company who CAN choose the best components does not mean that they actually do. A lower sale price means they're cutting costs somewhere, and I don't buy that the "bigger" brands (smaller brands?) only charge more because they can get away with it due to brand mystique.
 
#83
I would bet they don't have a human hand touch their PCB's after loading the bare board on the frames till it comes out of the cleaning bath? Automation is not a bad thing BTW, so that's not what I am saying. Just a lot cheaper from buying tape reel components to wave solder with greatly reduced labor costs.
 
#86
so judging by the msrp this could sell for a good bit cheaper than a vb-2. i've seen the bugera 1960 tube head selling for around 300 at a local shop and it retails for over 600....so this may be a very attractive product for first time tubers. i've never tried their amps, but i've used their mixers and a delay pedal that both worked out great for me. cant wait to hear a review.
 
#88
B-string said:
I would bet they don't have a human hand touch their PCB's after loading the bare board on the frames till it comes out of the cleaning bath? Automation is not a bad thing BTW, so that's not what I am saying. Just a lot cheaper from buying tape reel components to wave solder with greatly reduced labor costs.
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Watch some of the factory videos
[Invalid or Expired Link Removed]

They show hand assembly phases of construction. Sure the boards are probably wave soldered - so are Ampegs no doubt. It makes for consistent quality job.

Bugera does the same that all manufacturers claim, they test the tubes and reject ones that don't pass. Except they actually show a video of this going on.

All the tubes that don't pass go back on the market oneway or another. Internet and ebay sellers I bet.
 
#89
B-string said:
I would bet they don't have a human hand touch their PCB's after loading the bare board on the frames till it comes out of the cleaning bath? Automation is not a bad thing BTW, so that's not what I am saying. Just a lot cheaper from buying tape reel components to wave solder with greatly reduced labor costs.
Click to expand...

The circuit board in this EQ was touched by human hands.

http://www.talkbass.com/forum/showthread.php?t=286904

I've looked inside a lot of electronics. In the low cost region, a fair amount of surface mount boards are still soldered by hand. It's still a toss up between the cost of capital and the cost of labor.
 
#90
seamonkey said:
Watch some of the factory videos
[Invalid or Expired Link Removed]

They show hand assembly phases of construction. Sure the boards are probably wave soldered - so are Ampegs no doubt. It makes for consistent quality job.

Bugera does the same that all manufacturers claim, they test the tubes and reject ones that don't pass. Except they actually show a video of this going on.

All the tubes that don't pass go back on the market oneway or another. Internet and ebay sellers I bet.
Click to expand...

i won't argue with that vid, looks plenty legit to me. still curious where they're shaving off all the nickels and dimes to keep the costs that low, but who knows, if they sound good and don't break, why the heck not.

as i mentioned my experiences have only been with Behringer amps, not Bugera, perhaps they do things differently from brand to brand.
 
#91
So I looked at the vids. Sorry, not impressed. After a decade in manufacturing I didn't see the manufacture of the amps only testing, final assembly and someone playing around for the camera on one amp with no set pattern for quality testing. Not knocking the brand understand, just no real proof of anything other than standard testing of output tubes. Bench tests and final assembly. The R&B playing in the background was a nice touch, but the continued tapping of the output tubes would probably produce very small batches of finished product, no one has that much time in a manufacturing enviroment?
Just IMHO and IME....not sold by the video.
 
#92
MrTAteMyBalls said:
... i've seen the bugera 1960 tube head selling for around 300 at a local shop and it retails for over 600....so this may be a very attractive product for first time tubers. i've never tried their amps....
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Wow, that's cheap!

I have a 1960 and it sounds great for bass (through my Ampeg 8x10). There's a thread on the 1960 for bass and I'm getting pressed for some sound samples. I don't really have any easy way to record any but I'm trying to figure it out.
 
#98
agedhorse said:
The diodes are at 0 volts DC, and there's quite a bit of local feedback in the first stage, the second stage is the phase splitter, and the third section is a cathode follower driving the grids (no voltage gain) with some bias coordination.
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The diodes sit next to the external amp input, which is exposed to the elements. They sit at undefined volts AC and DC, which is why Ampeg engineers included a diode DC blocker and AC limiter.

My schematics for SVT power amps show one high gain stage with some local feedback and input of global feedback, into a phase splitter, into another gain stage, into a combined anode follower for driving G2 and cathode follower for driving G1.

Are you talking about a different circuit than the SVT?

agedhorse said:
I do not think there's enough gain for the output stage to be driven into clipping before the diodes begin to conduct
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I'm an engineer, and the schematics I've seen included valve names and their operating parameter. This makes it easy to calculate gain, so I don't have to think anything.

agedhorse said:
Sometimes there's more to a circuit than meets the eye
Click to expand...
If the schematics are correct, they correspond pretty much 100% to the circuits they describe.

This is only engineering. :hyper:
 
#99
Show some calculations and measurements to show the diodes are not conducting.
that's not a protection circuit.
Caps are used to block DC
The SVT has clipping diodes, there's no doubt. The diodes are there in the signal path. It is not an all tube path and they have fooled everyone for years.
Just take them out and see if the sound doesn't change. Measure it. You must have the tools being an engineer.
 
#100
Here is my SVT poweramp model in Proteus 7

svt-pa.png


and Oscilloscope window (yellow - input signal amplitude 0.2v, red, blue - power tubes grid voltage, amplitude near 45 V)

Oscil.png


So, as we can see, diodes are not conducting and grid voltage swing is enough to drive 6550's to their full power (with respect to bias about -45V) and input voltage can be raised without clipping.

If I set input voltage about 0.7V (or 1.4V Peak-to-Peak), then I can consider small soft clipping of diodes, but voltage swing on grids of power tubes are in some part of period out of 0 V and go into positive side which is class AB2 of operation, I hope SVT works in AB1.
 

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