I second that. I would find a newer amplifier of better quality to play with. Most Bogen products were part of the commercial market for 25 and 70 volt lines and while I didn't see a 25 or 70 volt tap I assume the output transformer is of low quality. While it might be fun to restore in all actuality it has no value.
My thinking is indeed trending towards the eBay option.
Besides, the Chief Cook & Bottle Washer just loves doing eBay listings, packing-up the stuff and getting good reviews. I just sold-off a dozen guitar speakers, and she was ecstatic. Have no idea what's going on there, but the fact remains that I get major Props when I sell-off surplus on eBay.
When next I'm into the undercarriage of the Bogen, I'll take a photo of that diode in the Voltage Regulator circuit. Has to be Selenium, I would think. I believe it's the only solid state thing in there...
Besides, the Chief Cook & Bottle Washer just loves doing eBay listings, packing-up the stuff and getting good reviews. I just sold-off a dozen guitar speakers, and she was ecstatic. Have no idea what's going on there, but the fact remains that I get major Props when I sell-off surplus on eBay.
When next I'm into the undercarriage of the Bogen, I'll take a photo of that diode in the Voltage Regulator circuit. Has to be Selenium, I would think. I believe it's the only solid state thing in there...
A selenium rectifier is cube shaped with fins. One sized for a bias rectifier is probably 1/2 inch on a side. The biggie I got out of a car battery charger as a kid was maybe 6 inches on a side.
A primitive silicon rectifier looked like a "top hat" with wires sticking out of the top and bottom. They were often called top hat rectifiers.
A primitive silicon rectifier looked like a "top hat" with wires sticking out of the top and bottom. They were often called top hat rectifiers.
Thar she blows...
You can't quite see it in the photo, but the "hot" lead from the PST is bare for about 1/2" where it's soldered to the rectifier.
The more I study this thing below-decks, the less inclined I am to power it up on the VARIAC. Looks like the bilge of a typical DYNACO kit, minus the ultralinear Iron.
In fairness, nobody was using thin rosin-core solder and a temp-controlled iron in those days, were they?
OTOH, HP and Tektronix stuff of the same vintage was pretty immaculate (clean solder joints, laced wires, nice layout) but commercial equipment did (and does) cost many times more $$$.
You can't quite see it in the photo, but the "hot" lead from the PST is bare for about 1/2" where it's soldered to the rectifier.
The more I study this thing below-decks, the less inclined I am to power it up on the VARIAC. Looks like the bilge of a typical DYNACO kit, minus the ultralinear Iron.
In fairness, nobody was using thin rosin-core solder and a temp-controlled iron in those days, were they?
OTOH, HP and Tektronix stuff of the same vintage was pretty immaculate (clean solder joints, laced wires, nice layout) but commercial equipment did (and does) cost many times more $$$.
Your wife's nail polish "rides" to the rescue. 2 layers of that stuff on the uninsulated section of wire should restore a margin of safety. Thankfully, this is a comparatively low voltage situation.
You may be dealing with deteriorating cloth wire insulation. Nail polish, followed by polyolefin heatshrink tubing, can resolve the matter.
You may be dealing with deteriorating cloth wire insulation. Nail polish, followed by polyolefin heatshrink tubing, can resolve the matter.
Chief Cook & Bottle Washer
A most excellent suggestion.
In the normal scheme of things, The Chief Cook & Bottle Washer (aka "Oma") does not wear nail polish.
Fortunately, I gave her a bottle of Jet Black (goth) nail polish in her stocking for Xmas as a bit of a joke; the CC&BW is pretty much the OPPOSITE of "goth".
And, of course, I have meters & meters of polyolefin shrink wrap.
The issue is what happens at VARIAC power-up, since I want not to touch the thing until I see what I got. Guess I'll just browse through the circuit looking for suspect areas...
Stayed tuned, boys & girls.
A most excellent suggestion.
In the normal scheme of things, The Chief Cook & Bottle Washer (aka "Oma") does not wear nail polish.
Fortunately, I gave her a bottle of Jet Black (goth) nail polish in her stocking for Xmas as a bit of a joke; the CC&BW is pretty much the OPPOSITE of "goth".
And, of course, I have meters & meters of polyolefin shrink wrap.
The issue is what happens at VARIAC power-up, since I want not to touch the thing until I see what I got. Guess I'll just browse through the circuit looking for suspect areas...
Stayed tuned, boys & girls.
Here is the price for all original tube power amp (a more prestigous one):
original 91B Western Electric Tube Amplifier ~ early 300A Theater Amp theatre | eBay
And here is the price what an "updated" by Mr. Clever and Smart with new parts equipment is worth: $ Zero. Because its no longer an original. Not many get this idea in Audio, it seems.
Happy modding, "improving" and altering with new parts!
original 91B Western Electric Tube Amplifier ~ early 300A Theater Amp theatre | eBay
And here is the price what an "updated" by Mr. Clever and Smart with new parts equipment is worth: $ Zero. Because its no longer an original. Not many get this idea in Audio, it seems.
Happy modding, "improving" and altering with new parts!
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Zener idea goes to before WWII. Zener product apparently existed in 1953, in a specialized (and maybe BellTel) app, but it had to be explained.
Do not diss the older Bogens. Really any Bogen; they did what they were sold to do. Early intercoms intercommed. But as late as 1955 the HiFi were David Bogen's personal projects, dressed-up to sell to well-heeled buyers. The Bogen company was sold in late 1950s so you get the School Amps and such.
https://www.bogen.com/aboutus/aboutbogen/docs/DavidBogenArticleweb.pdf
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Well, for some people it was just school PA.
I love the Bogen sound!
BOGEN DS 265 TUBE AMP - YouTube
I love the Bogen sound!
BOGEN DS 265 TUBE AMP - YouTube
I will gladly trade my Bogen for ONE of those 300As.
Probably even a burned-out one....
This was just to inform that an original amp is worth something, but a "refined and competently enhancedor modded" version, done by Clever and Smart Audio Engineers, is mostly not.
P.S. The owner did use a Sovtek 300B to demonstrate the amps function. So this amp misses the original tube set.
P.S. The owner did use a Sovtek 300B to demonstrate the amps function. So this amp misses the original tube set.
Wow
That's a LOT of money for iron and some ancient "passives".
Of course, IIRC, it had interstage iron, so there's THAT.
MY point was that a Western Electric 300A/B theatre amp is an historically important, nay, maybe THE MOST historically important audio amp ever.
Can you think of one that comes close? I can't.
It's analogous to ALTEC VOT horn speakers which sat behind every screen in America, which also get crazy money, considering that you need to live in an auditorium to use them effectively (I know; I've tried)
The Bogen DB-130? Meh. If I had a Mid-Century Modern bungalow in Palm Springs, and wanted authentic bric-a-brac, it would be perfect.
We shall see; I'm certainly not going to cut into it before I see what Mister Market has to say. OTOH, I ain't holding my breath.
That's a LOT of money for iron and some ancient "passives".
Of course, IIRC, it had interstage iron, so there's THAT.
MY point was that a Western Electric 300A/B theatre amp is an historically important, nay, maybe THE MOST historically important audio amp ever.
Can you think of one that comes close? I can't.
It's analogous to ALTEC VOT horn speakers which sat behind every screen in America, which also get crazy money, considering that you need to live in an auditorium to use them effectively (I know; I've tried)
The Bogen DB-130? Meh. If I had a Mid-Century Modern bungalow in Palm Springs, and wanted authentic bric-a-brac, it would be perfect.
We shall see; I'm certainly not going to cut into it before I see what Mister Market has to say. OTOH, I ain't holding my breath.
Another thread at another place involving a DB130.
https://www.lencoheaven.net/forum/index.php?topic=37136.0
Regards,
https://www.lencoheaven.net/forum/index.php?topic=37136.0
Regards,
I have a mono system myself (which is what got this whole thing started), with
I am building a Salas SSHV2 shunt supply for the preamp; not sure any vintage preamp (let alone the DB-130) will be in the same league.
My shop system uses a TubeLab Simple SE modified to also accept 6AV5GAs (w/ outboard sockets); I am running those at ~23 watts dissipation (~330Vp, 70ma), effective double the book value. We'll see how much abuse those little sweep tubes can actually take. Alternately, a recently recapped Quad 303 (for British music, particularly Keef & Mick).
Not sure where the the DB-130 would fit into this scheme. Maybe in lieu of the Quad 303, but I don't need the preamp section in the shop...
- Rek-O-Kut N33H with Empire 980 arm and Denon DL-102 "compliant mono" cartridge
- PhonoDude phono preamp
- 417A/300B version of TubeLab's Simple 45 amp (CCS on top of 417A) with regulated power from Heathkit IP-32.
I am building a Salas SSHV2 shunt supply for the preamp; not sure any vintage preamp (let alone the DB-130) will be in the same league.
My shop system uses a TubeLab Simple SE modified to also accept 6AV5GAs (w/ outboard sockets); I am running those at ~23 watts dissipation (~330Vp, 70ma), effective double the book value. We'll see how much abuse those little sweep tubes can actually take. Alternately, a recently recapped Quad 303 (for British music, particularly Keef & Mick).
Not sure where the the DB-130 would fit into this scheme. Maybe in lieu of the Quad 303, but I don't need the preamp section in the shop...
What is of interest to me in the DB-130 is the obviously competent power transformer. Consider a GZ37 rectifier into a choke I/P filter and the full 350 mA. of B+ could easily be available. That's enough "juice" for a PP KT88 stereoblock.
Coincidentally, I actually FOUND a spare DB130 PST while doing further transformer inventory (as well as all the iron to make ONE Heathkit W4AM monoblock(!)).
Apparently I was at one time in the process of becoming a "Bogen guy".
I think that's before I actually got single-ended amps to work well (which of course depends on an entire supporting cast, especially stupid efficient speakers).
Let me review the inventory when done; that one may go on FleaBay right away.
This evening I am cataloging the Turntables, especially trying to figure-out why there are FOUR Thorens of different vintage, and what I was possibly thinking...
Apparently I was at one time in the process of becoming a "Bogen guy".
I think that's before I actually got single-ended amps to work well (which of course depends on an entire supporting cast, especially stupid efficient speakers).
Let me review the inventory when done; that one may go on FleaBay right away.
This evening I am cataloging the Turntables, especially trying to figure-out why there are FOUR Thorens of different vintage, and what I was possibly thinking...
PS I THINK there's enuf 5V juice to contemplate a PAIR of rectifier tubes; there ARE two 5Y3s on the earlier DB-130 (NOT the "A" model) so at least 4 amps...
A GZ37 draws 3A. of heater current. A pair of 5Y3s can produce up to 250 mA. of B+ current. The GZ37 is rated for 275 mA. into a cap. I/P filter and 350 mA. into a choke I/P filter. The DB-130 schematic shows a cap. I/P filter and (obviously) more than 125 mA. of B+ are available. The full RMS current of the rectifier winding is available as B+, when choke I/P filtration is employed, which is not the case when a cap. I/P filter is used.
A very rough estimate of GZ37 rectified and choke I/P filtered processing of the DB-130 power trafo's 490-0-490 winding is 415 VDC and 350 mA. SS rectification would make a few more volts available, along with whatever the full RMS current capability of the CT winding happens to be.
A pair of 5AR4s would not overwork the 5 VAC winding, but I highly doubt the max. 500 mA. of B+ the tubes are capable of would be available.
A very rough estimate of GZ37 rectified and choke I/P filtered processing of the DB-130 power trafo's 490-0-490 winding is 415 VDC and 350 mA. SS rectification would make a few more volts available, along with whatever the full RMS current capability of the CT winding happens to be.
A pair of 5AR4s would not overwork the 5 VAC winding, but I highly doubt the max. 500 mA. of B+ the tubes are capable of would be available.