The beauty of Bogen
- Thread starter Tube Sound
- Start date
yeah not original. It should have 5AR4 or 5CU4. I'd never seen a 5CU4 before, and this is the only thing I've ever seen that actually called for one. Thought perhaps I was seeing a unicorn.
s-petersen
Scott
I had a Fisher 55a, and it took two 5AW4's another odd rectifier
The only thing I didn't like about the DS-265 is how damn close those GZ34 rectifiers were to the power transformer. Other than that, it's a beautiful beast!
Goldenbogen
Active Member
Goldenbogen
Active Member
Thanks gadget. Always the first to answer. 
rpampt
Analogeous Vinylitis
I noticed my pic has disappeared, so adding a link to the cosmetic upgrade of my MO 200A, after Dave Gillespie brilliantly converted it to the "Mighty Bogen" and chronicled in the link that Gadget included a page or 2 ago.
Here is the cosmetic work that I worked through with some pics. Still my main amp.
https://audiokarma.org/forums/index.php?threads/facelift-for-the-bogen-mo-200a.582567/
Here is the cosmetic work that I worked through with some pics. Still my main amp.
https://audiokarma.org/forums/index.php?threads/facelift-for-the-bogen-mo-200a.582567/
Superman541
Well-Known Member
I noticed my pic has disappeared, so adding a link to the cosmetic upgrade of my MO 200A, after Dave Gillespie brilliantly converted it to the "Mighty Bogen" and chronicled in the link that Gadget included a page or 2 ago.
Here is the cosmetic work that I worked through with some pics. Still my main amp.
https://audiokarma.org/forums/index.php?threads/facelift-for-the-bogen-mo-200a.582567/
That thing is gorgeous!
Bogen gear was underrated, probably due to their PA, Sound Reinforcement priorities. Some of their amps have exceptional iron. Their HO-10 pp DHT triode amp was a good example of this, circa early 1950s. The DS-265 is another great example from a little later. The MO-200A is a huge amp, even when dressed up. It uses the same opt. trans. as the MO-100A. Two MO-100As would be my preference over the 200A, with separate power trans. Those 100W output trans are outstanding ! Very wide bandwidth, plus a tertiary feedback winding.
Back in the early 1950s, Bogen attempted to market a transcription type, full function preamp. The multi-EQ curve, phono stage was perhaps the first cascode configured phono preamp. I am the lucky owner of a pair of these PR-100A preamps. While the switchable phono EQ is great for record collectors, the complex line stages with loudness, tone and filter stages could be the drawback which hindered sales. These took five years for me to pair up. Underneath, inside, the wiring is very, very impressive. Sleeving and lacing of the wiring looks so good, I have hesitated from "upgrading" the complex circuitry.
I also have a really cool, Bogen push-button switchbox, a passive phono EQ add-on, in a small, rectangular case. Pics to come...
Of course, Bogen-Presto merged and fortunately marketed the Lenco L-70 idler table as a Bogen-Presto B-62, a unit which awaits my resto.
Bogen made many "sleepers" still under the radar, thankfully...Enjoy !
Back in the early 1950s, Bogen attempted to market a transcription type, full function preamp. The multi-EQ curve, phono stage was perhaps the first cascode configured phono preamp. I am the lucky owner of a pair of these PR-100A preamps. While the switchable phono EQ is great for record collectors, the complex line stages with loudness, tone and filter stages could be the drawback which hindered sales. These took five years for me to pair up. Underneath, inside, the wiring is very, very impressive. Sleeving and lacing of the wiring looks so good, I have hesitated from "upgrading" the complex circuitry.
I also have a really cool, Bogen push-button switchbox, a passive phono EQ add-on, in a small, rectangular case. Pics to come...
Of course, Bogen-Presto merged and fortunately marketed the Lenco L-70 idler table as a Bogen-Presto B-62, a unit which awaits my resto.
Bogen made many "sleepers" still under the radar, thankfully...Enjoy !
I'd like to get my hands on a PR2 preamp. It was a stereo unit, and would have been a companion to my DS-225. Its the lesser known little brother to the DS-265.
I run a pair of MO-100a's. In their current form they do not use the feedback winding though. Apparently its not very linear and end results are less than ideal. I forget the particulars but Dave explained it in his modification thread. Had the same problem with my Rauland-Borg amps. The frequency response measured at the feedback winding was ruler-flat, at the speaker terminals it fell off a cliff after about 5khz.
I run a pair of MO-100a's. In their current form they do not use the feedback winding though. Apparently its not very linear and end results are less than ideal. I forget the particulars but Dave explained it in his modification thread. Had the same problem with my Rauland-Borg amps. The frequency response measured at the feedback winding was ruler-flat, at the speaker terminals it fell off a cliff after about 5khz.
s-petersen
Scott
When I sold mine, it went for less than $200. I like he way the indicators for the settings lit up, there were 8 neon bulbs behind the faceplate, it's like they use LEDs today
s-petersen
Scott
I believe I sold the preamp 2 years before the amp, otherwise I would've mentioned it at the time.
s-petersen
Scott
Bogen certainly did things in a unique way!
Goldenbogen
Active Member
Whats with the pr2? Amp. Channel. Tubes?