Bogen Rp200

[Toxophilite]

Hmm
Picked this up for $25 the other day, missing most of the tubes but I did get a nice pair of telefunken 12AT7
Normally I'm loathe to dismantle stereo tube amps but the multi-tap (4, 8 , 16) OPTs are sure tempting
THey look pretty beefy compared to the AO-43 OPT I held next to them (probably as a result of being multitap)


It's 2 channels of pushpull 7189 which can handle plate voltage up t0 440vdc and can put out 10 watts each
The amp is rated at 20 watts a side
These might be good OPT upgrades for my deluxes..hmmm


Seems a shame though

[Ed_Chambley]

Early 60's receiver. Nice score for $25.  It looks like it is very salvageable.  This unit has a decent phono stage.  In the audio world I think Bogen is underrated.  No it is not a Fisher 500, but it is a very good sounding receiver.

I don't think the OT's are larger because of multi taps, it is likely they have a much larger Bandwidth.  Sure, you can build a deluxe with the iron.  I am using a similar Stromberg Carlson stereo amp.  Long term project, but so far I have it with Dual OT in mono switching off one of the OT's for a half power except mine is 10 watts per channel.

Lots of things can be done with these, but if you do not have a tube stereo you may want to hear it before dismantling.

[eleventeen]

Fantastic $25 buy, congrats! I am always looking for trashed stereo tuners w/integrated amps. That might fetch $200+ on ebay because it appears to be in physically very nice condition, not trashed at all. But that would of course require of course tubing and testing. Agree, very beefy iron there.


As for replacing OT's on a Deluxe, that will seriously change the nature of your Deluxes, into much more of a full-range hi-fi situation. I have no way of knowing if that would be desirable for you. Those trannies look to be 6L6-capable to my eye. Of course the pair concept has got to be tempting with your pair of Deluxes.


If you could stand up or orient the two chassis next to each other, you could temporarily solder one of those trannies into one of your Deluxes as an experiment. We are talking 5 or so wires strung between one chassis and the other, right? Not the worst thing my bench has ever seen. You'll likely have to fiddle with your neg feedback resistor, but again...not that difficult.

[PRR]

> 7189 which ....can put out 10 watts each

This is a two-channel ~~20 Watt per channel push-pull power amp.

Not any 10 Watt amps. A single 7189 can only do like 6 Watts; it needs to work against another to team-up for the 20 Watts.

Also these OTs are push-pull, and will be very unhappy if you try them single-ended.

Two tubes and one OT is the big-end of an "18 Watt", a popular configuration (usually seen with 300V EL84 instead of 400V 7189).

7189 is become scarce; most modern Guitar-Market "EL84" will stand 400V over a useful life (because so many were over-abused in guitar amps). The Russian "equivalent" may not be happy at higher voltage.

The obvious thing is to fill it with power-stage tubes, and cobble the front-end to more guitar-like preamplification. This might just mean whacking-out half of the phono preamp to give one stage with no EQ and hi-Z input. The volume and tone networks are perfectly usable for guitar amplification. There's probably a mono switch to feed the one guitar to both power amps. You may wish to lighten-up the NFB from speaker to the stage before the power tubes. Presto: a 40 Watt stereo/mono monster which is over-weight for guitar but also able to reach far below 50Hz for bass application. Retain the Tape In and jack your iPod through for break music.

[Toxophilite]

It is rather a large beast to use in it's current configuration as a guitar amp!
Too square! not long and narrow enough. I made a 40 watt amp out of trashed mono Sherwood S-1000 once and I had to hang it from the face plate (with special added supports)to fit it in a cabinet, then all the tubes were on the iniside!



I did know it was a pushpull amp (it has sockets for 4 power tubes!)


I was referring to a single 7189 tube though perhaps my first sentence was a a little confusing



"It's 2 channels of pushpull 7189 which can handle plate voltage up t0 440vdc and can put out 10 watts each
The amp is rated at 20 watts a side"


I should have said:



It's 2 channels of pushpull 7189.
The 7189 can handle plate voltage up t0 440vdc and can put out 10 watts each in pushpull
The amp is rated at 20 watts a side


Does this mean I have to buy an ipod??  waaaaa  I'm still resisting cell phones etc.

[eleventeen]

I almost dislike getting something like that in such good condition. It seems like such a shame to tear it apart and I'd feel bad doing so.

[DummyLoad]

find a pair of AR 2x or any modern efficient bookshelf hi-fi speakers and fix it up as a bench stereo. 


--pete

[Toxophilite]

yeah I feel the same way
It's in decent condition despite needing a schwack of tubes
4 7189 (I have 2!)
3 12AX7 (have lots of those)
2 7247 ( I have one)


then it would probably be prudent to recap the power supply


I might save it or I might flip it.hmmm