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BVV3000 INFINIUM Trial

#261
SergevanR said:
I own a bvv3000, and also had some issues. A friend of mine took a look at it and measured some things. There was over 630v going through the poweramp valves, 6550 valves are Max. 600v so he tuned it to 580v to be safe. Still running the 6550's without a problem. KT88 can run up to 800v, so maybe that's worth a shot. Also swapped out all of the pre amp valves, big difference. More power and less noise. Next step is new power amp valves.
I use a peavey 115 350w eminence 8 Ohm and a 410 400w 8 ohm xl series Hartke with the BVV.
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Would you care to explain how the B+ voltage was adjusted???
 
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#266
SergevanR said:
It works. Another solution is switching to KT88. At least when on unstable 220v grid.
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Maybe "it works", but it doesn't change the plate voltage.

KT-88's MIGHT be a better solution, but some amps are not stable with the KT-88 and the results can be "spectacular" if not. If Bugera recommends the KT series as being compatible than that's probably the better way to go, though my experience has been that (in general) the 6550 tube is more robust overall.
 
#267
Less power going in, less power to to
agedhorse said:
Maybe "it works", but it doesn't change the plate voltage.

KT-88's MIGHT be a better solution, but some amps are not stable with the KT-88 and the results can be "spectacular" if not. If Bugera recommends the KT series as being compatible than that's probably the better way to go, though my experience has been that (in general) the 6550 tube is more robust overall.
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6550 has Max plate 600 volts and my amp was at 632v, so that's too much. That's why my friend tuned down the voltage going in before the biasing infinium circuit. 580v on the plates, that's all I can tell you. I'll ask him if he can write everything down and put it up here.
 
#268
SergevanR said:
Less power going in, less power to to

6550 has Max plate 600 volts and my amp was at 632v, so that's too much. That's why my friend tuned down the voltage going in before the biasing infinium circuit. 580v on the plates, that's all I can tell you. I'll ask him if he can write everything down and put it up here.
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But the plate voltage CAN'T be turned down.

The plate voltage measurement MUST be made with the amp already biased, the very act of drawing quiescent current through the output stage will drop the voltage due to the supply impedance. The bias will affect the MEASURED plate voltage, which is why it must be set before measuring.
 
#270
Sparky Mark said:
Hi SergevanR, could you describe the issues that you were having which prompted you to give it to your friend please? Many thanks again. Mark
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After turning the power on, everything is going fine. After a while, when the amp was warm, the volume dropped dramatically and had a lot of overdrive.When turning it off and back on again it was okay for a few minutes. When turning down the volume on my bass or keeping it silent, it happened again.
 
#271
Sparky Mark said:
Adriano, could you explain what was wrong with your PSU module and how was it fixed please?
Thank you, Mark.
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Well, just right before going silent (blown fuses?), my unit was emitting strange noises through the cabs and after playing with it for about 1h, it went standby on its own. I noticed earlier in that week the infinium leds always lighted up randomly as supposed to. The next day I powered it, I just listened the fuse blowing. As it was under warranty, I didn't try do disassemble it as I suspected it was more than a power tube issue. I doubt audio systemas will tell me specifically what is the problem, but I'll try to ask them.
We all noticed there are maybe design issues, possibly with powering the tubes and, without an schematic, it will be very difficult to guess was does what.
Maybe the users could start by measuring their voltages and posting them. Maybe that would point out a few things?
 
#272
IMG-20170312-WA0005.jpg
 
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#274
I really wish we knew how many BVV3000i have been manufactured and sold. Less than a dozen Talkbass members seem to own one? From this small sample two or three owners are reporting regular use with few or no issues whilst others have had problems. Bugera produces (and I assume sells) a large number of different valve heads which use the Infinium auto bias circuit.

Admittedly I haven't spent a lot of time searching for reports of problems with Bugera's other infinium heads but this type of circuit is accepted within the audiophile market and seems to be working for their guitar heads. I wonder if it is having problems because of the higher power of the BVV3000i and if certain components are near (or marginally outside) their required design tolerance then it falls over?
Good units stay good and marginal units suffer problems?

Unfortunately I only use mine at home so I cannot comment on its ruggedness but I suspect any manufacturing short cuts could be exposed during transit.

I will say however that it is a fantastic sounding head and has convinced me that tube power amps are the best even though I am content to gig solid state.
 
#275
SergevanR said:
View attachment 1086406
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Looks just like ... down to the clipping diodes

Bugera has the real secret in the Infinium. I imagine if a voltage is changed to the input of the Infinium it measures and recalculates all the rest. I don't think Bugera would have though of somebody changing an external resistor. So far this is the most reverse-engineering, and hot rodding I've seen on this head. It may be just a start.
T me, this is part of the "Right to Repair" which consumers don't have for most modern gear. A good warranty and support could be substituted for right to repair, but I still hope Bugera actually releases service manuals, theory of operation, to allow techs outside the Bugera service centers to repair their gear.
 
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#276
seamonkey said:
Looks just like ... down to the clipping diodes

Bugera has the real secret in the Infinium. I imagine if a voltage is changed to the input of the Infinium it measures and recalculates all the rest. I don't think Bugera would have though of somebody changing an external resistor. So far this is the most reverse-engineering, and hot rodding I've seen on this head. It may be just a start.
T me, this is part of the "Right to Repair" which consumers don't have for most modern gear. A good warranty and support could be substituted for right to repair, but I still hope Bugera actually releases service manuals, theory of operation, to allow techs outside the Bugera service centers to repair their gear.
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That's right, the infinium circuit recalculates everything, so that system works great.My friend is going to put in some orange drops or Mallory's and also a few new condensators. Just to make it more stable and quieter. At the moment maximum amount of output is about 35w per valve. It's the best it can do without changing the tran's and firmware of the infinium which seems to be unobtainable.
 
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#277
That schematic looks exactly like an ampeg svt which this amp is essentially an replica of.
I'll have to look at pics of mine to see if the plate load resistors are there, if so, I suppose those values could be raised to put less voltage at the plate of the tube but those would need to be very high wattage to work.
Also, that is not over voltage for 6550's no matter what the textbook specs say, I'm assuming your "tech" has never worked on, looked at schematics or learned anything about any other high wattage tube amp that uses 6550's because those all run 650 volts or more for the b+! Like the SVT! If he doesn't know that, I wouldn't trust him to work on an amp.
Just my biased opinion....
 
#278
The infinium mostly just checks voltage drop across I believe a 3.7 or 4.7 ohm resistor in the cathode of every power tube and adjusts the bias voltage of each tube to maintain the same voltage across that resistor.
It doesn't adjust plate voltage or anything like that.
There is other "magic" going on that I'm assuming checks for tubes out of the acceptable range and will turn off pairs of tubes and other things if it gets out of hand. I wonder if that's what happened with mine, maybe a tube or two of mine are way out of acceptable range forcing a fault condition. Still have to check them. The bugera tubes are the next ones to be tested.
Last night was spent testing 18 ge's I have and finding out all of them are bad....
That sucked to find out!!!!
 
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#279
Sparky Mark said:
this type of circuit is accepted within the audiophile market
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Many times I heard proper biasing is a compromise between good sound and reasonable tube life.
The audiophiles seemed to be OK with shorter tube life in favor of audiophile performance.
It is surprising Infinium doesn't have some options to switch, but maybe in the future?

I don't think Bugera stopped making the BVV3000 because of any real design problems, I think there's just a much better market and margins in their other amps.
 
#280
timv said:
The infinium mostly just checks voltage drop across I believe a 3.7 or 4.7 ohm resistor in the cathode of every power tube and adjusts the bias voltage of each tube to maintain the same voltage across that resistor.
It doesn't adjust plate voltage or anything like that.
Click to expand...
Correct, the statement that the PLATE voltage was adjustable just served to spread more internet myths and falsehoods.
 

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