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BGW amp 750B anyone familiar with it ?

sfox52 said:
Thanks Elliot! Yep, the spec for the 500d is 200 into 8
ohms, 251 into 4 ohms. The 750a is 200 into 8 & 300 into 4. Mine does seem like more than that, and it so happens that I have some 21000 uf caps that will fit the 2 inch mounts.
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The difference between amplifiers of yesterday and today is the THD % @ the stated wattage.

Amplifiers today will list 0.1 - 1% THD @ the given wattage.

Amplifiers of yesterday listed 0.0008 - 0.05% THD @ the given wattage.

The larger capacitance is better for high current conditions. If you are bi/tri-amping, keep the 750 on bass. They usually perform best under those conditions.

Best Regards,
 
I guess the money question is- can I take a 750a module & drop it on to the 500d? I'll be putting out feelers for a parts unit if so..
 
sfox52 said:
I guess the money question is- can I take a 750a module & drop it on to the 500d? I'll be putting out feelers for a parts unit if so..
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I don’t believe such a modification would be that simple in addition to being noticeable.

Bear in mind 250 watts versus 300 watts yields only a + 0.79 dB gain in terms of output. Humans need to hear + 3 dB for a noticeable difference

The most you can do is compare the schematics amongst both designs to see if it is possible. However, if the goal is to gain more wattage, your power supply (Power Transformer), will more than likely, be the limiting factor.

In my opinion it is not worth it.

Best Regards,
 
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Elliot- thanks again! I'll just use it as is- you are correct about the bass performance! I'm gonna look into an active x-over & try it with the SKA for the treble amp.
 
bgw 750a is a great amplifier a real workhorse. i have mine bought it for 102 dollars cleaned her up and re soldered all connections , has excellent vocals and bass!! massive transformer. would like to see more bgw fans
 
Some More BGW Love model 1000!

Just parted ways with my minty GTA which has allowed this one to achieve "keeper" status. It may become eligible for some replacement caps in the future, but as of now it is dead silent and shows less than 2 mV of offset on either channel. It's the rarest BGW model i know of, and was their first commercially produced amplifier, with circuitry designed by the ex RCA engineer who also engineered the output transistors it uses. Some of you have probably seen a couple of these pics before, but here they are in an open forum for everybody's perusal.

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bgw4.jpg


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bgw2.jpg
 
I'm jealous of that Model 1000, bowtie! I put my 500D back in service in the cave a couple days ago. I'm going to plumb a remote fan duct from another room- makes a nice space heater during extended listening. I may build a couple small subs & use the beast for them.
 
bowtie that is beautiful it it similar to the 750a but layed out different , the 750 had more heat sinking, very nice what is the output ? jack sondermeyer designed it ? do you use it ? it is very clean inside. wow 2 relays per side! keep them bgw's comming! I really like the design easy to service
 
Bgw!

As a new member it's great to see a group of BGW owners and enthusiasts. I worked for a BGW dealer in the 1980's and grew to love them. I currently have a 750B, 250C, 500D and a 7500 that was custom built for me in 1982. All except the 7500 have XLR inputs but work wonderfully.Those that haven't heard a big BGW or a few in bi or tri-amped setups with appropriate speakers (like those for professional sound reinforcement as opposed to home audio) haven't scratched the surface of what is possible with the right equipment.
I have a huge pair of Sonic bottoms still in storage I used with the 750B and 500D in bi-amp mode with Ashley crossovers. The Sonics have a huge horn and 2 12" EV Gold professional series drivers. They weigh 138lbs each and are as solid as the BGW's. I also have a pair of old Shure Vocalmaster columns that I ran with the 250C as a tri-amp setup.
I'd EQ the system out flat with my RTA then tweak the third-octave equalizers to get it "right". I ran everything with a Tascam 688 Portastudio as a board in XLR into a T.C. Electronic Finalizer Express to the Soundcraftsmen eq's to the crossovers The amps were connected to the speakers with original big Monster cable I got for free when we remodeled night clubs, bars and discos. I used a HHB 850 for CD's, a Tascam 122 mk III for cassettes and Tascam DA-30 and DA-45 DAT decks for anything else.
To say it was an "experience" to hear is kind of an understatement. You could feel the kick-drum pedal hitting the drum head, the tips pf the drumsticks on cymbals, tell a Fender Super Reverb from a Twin Reverb or a Marshall from anything else. R&B, Jazz, Blues, rock and anything else fed into it was as good or bad as the source material. I don't think any other amps could do what the BGW's do. I had it setup in my old living room/recording studio for a few years and I've never heard anything better in a house. The only downside was it took a 100 amp electrical system upgrade and I had to turn the amps on one at a time. I still have all of it scattered here and there but hope to put it back together one day. The BGW's were what started it and were the heart of it all.
 
GordonW said:
BTW- when BGW went out of business, Peavey (the musical instrument and PA company) hired many of the engineers from BGW, and bought much of the documentation from them. The Peavey CS800- the original model, as seen here:

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... IS just a BGW 750, with a few mods for durability and usability in a PA environment (more aggressive protection scheme, compressor/limiters built in, and such).

So, if you can find a tech that's familiar with the CS800, they can pretty much inherently work on the BGW 750, should it ever need service. The same caveat as the CS800 applies here- you do need to remove the top cover, and blow out the dust once in a while... that heatsink design seems to just catch dust and hold it, until it piles up into a "carpet" and smothers the heatsink. Barring that, they're nearly indestructible, from a normal-use standpoint...

Regards,
Gordon.
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My memory of Peavy from that era was that they produced a durable amplifier that was affordable to the working musician. Most of my experience was with the bass combos of the time, but I have to say that they sounded pretty bad as a whole.

By the time I was doing PA work the earlier CS-800's were still ubiquitous but not the current model. I did sound at a huge festival in Tuscan. The PA company had a huge stack of CS-800's along a similar stack of their ubiquitous horn loaded 15 and horn loaded 1" tweeter boxes (SP-10?). It was loud, dark and unmusical, but it got the job done.

I worked with a very good drummer in San Antonio who used a CS-400 on his electronic drum rig. I have to say that the sound was dull and lifeless. His rig sounded much better when I subbed a QSC 1400. Big improvement.

Their later PA gear, including the later CS800's improved and when they started selling the PA boxes with the 2" drivers the sound improved exponentially, but even then, it was not in the same class as say a QSC with JBL rig. I did sound for a band in a large venue and put my JBL rig side by side with his Peavy rig. While the Peavy system didn't sound bad at all, and cost about a third less, the JBL system was far more refined.

Maybe it was the sound of those hard limiters that made them sound so dull. Did the first CS-800's have the limiter?
 
Bgw updates

INCORRECT "BTW- when BGW went out of business, Peavey (the musical instrument and PA Company) hired many of the engineers from BGW, and bought much of the documentation from them."

CORRECTION. When BGW went out of business, Barbara Wachner sold it to ATI (Amplifier Technologies Inc). ATI purchased the assets of BGW Systems. Morris Kessler (Mr. ATI) hired Steve Lyle who was the last engineer from BGW. I have history of BGW as I was the VP of engineer for 8 years. I designed all of the amplifiers during my time @ BGW.

Jack Sondermeyer was a good friend and worked for RCA as an application engineer. Yes Peavey hired Jack Sondermeyer in the mid 70’s as their chief designer for their amplifiers. I was still working for Acoustic Control Corp. until I joined BGW in May 1978. Hartley did not steel/hire engineers from BGW.
Duke Aguiar 1/23/2011
 
The only manual I have is available online- it's for the 500D/750A amplifiers. It's not a sexy read, componants & schematics, troubleshooting guides, specs. I like the sound of mine, though I tend to use it when the A/C isn't needed.
 
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