This Friday at the New Jersey Antique Radio Club meeting we had a mini auction. I purchased this 6V6 push-pull stereo amp for $12.00, not bad if I have to say so myself. Its missing its 7199 tubes (I have a spare from my Dynaco ST-70) and the EZ81 tube.
This will make a nice base for a DIY tube amp, or restoration when time permits.
This will make a nice base for a DIY tube amp, or restoration when time permits.
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Nothing wrong with that! I never pass up a chance to buy a tube amp for the price of lunch. You could sack it for parts, restore it for a secondary system such as for your workshop, or, as you suggest, use it as the basis for something new and better.
Sal,
Jim McShane is a good person to pick an EZ81/6CA4 up from.
Since the 'AQ5 and 6V6 are "equivalent", your Bogen is a good candidate for conversion into an "El Cheapo" variant. The Bogen O/P "iron" seems to be on on the small side. That suggests to me you should follow the schematic for both triode wiring and "28" Hz. -3 dB LF limit. The 'T7 splitter/driver should run at Ib = 3 mA. and have 200-220 V. on the plates. Conversion to SS B+ rectification is therefore indicated. The vacuum rectifier "hole" will not be empty. A 6V4/EZ80 will do nicely as a B- rectifier.
Jim McShane is a good person to pick an EZ81/6CA4 up from.
Since the 'AQ5 and 6V6 are "equivalent", your Bogen is a good candidate for conversion into an "El Cheapo" variant. The Bogen O/P "iron" seems to be on on the small side. That suggests to me you should follow the schematic for both triode wiring and "28" Hz. -3 dB LF limit. The 'T7 splitter/driver should run at Ib = 3 mA. and have 200-220 V. on the plates. Conversion to SS B+ rectification is therefore indicated. The vacuum rectifier "hole" will not be empty. A 6V4/EZ80 will do nicely as a B- rectifier.
Eli,
I did notice the iron was a little small. I probably won't rebuild this amp the more I think about it as there are a ton of capacitors under it plus I am missing the top cover not to mention I have my Dynaco ST-70, Dynaco SCA-80 (I know, its S.S.), Scott 299B, Lafayette and Knight integrated amps. I will use many of the parts including the iron to build another amplifier with bass and treble controls. I took a look at your El Cheapo, nice simple amp, I can use your schematic for the base of my amp.
I am in the process building a 6V6 SE amp now (photo attached) utilizing scraps I have laying around in my basement.
This is a great forum to subscribe to, a lot of knowledge is among us here.
PS: You live probably 20 miles from me...
Thank,
Sal Brisindi
I did notice the iron was a little small. I probably won't rebuild this amp the more I think about it as there are a ton of capacitors under it plus I am missing the top cover not to mention I have my Dynaco ST-70, Dynaco SCA-80 (I know, its S.S.), Scott 299B, Lafayette and Knight integrated amps. I will use many of the parts including the iron to build another amplifier with bass and treble controls. I took a look at your El Cheapo, nice simple amp, I can use your schematic for the base of my amp.
I am in the process building a 6V6 SE amp now (photo attached) utilizing scraps I have laying around in my basement.
This is a great forum to subscribe to, a lot of knowledge is among us here.
PS: You live probably 20 miles from me...
Thank,
Sal Brisindi
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That looks like a DB-212 - I have the Sams folder scanned... let me know if you want ia copy.
If it wuz me.... I'd rewire the 7199 sockets for 6GH8 / 6U8 / 6BL8, since I have dozens, and ZERO 7199s...). As I recall it's 3-4 wires to move...
If it wuz me.... I'd rewire the 7199 sockets for 6GH8 / 6U8 / 6BL8, since I have dozens, and ZERO 7199s...). As I recall it's 3-4 wires to move...
Tom,
I hear you, I do have 5 6GH8 tubes to play with, I rather leave the 7199's for the Dynaco.
The Bogen amp is model BD-212. I would appreciate a copy of the schematic whenever you have a chance to email it. My email address is salb203 at optonline dot net
Thanks,
Sal Brisindi
I hear you, I do have 5 6GH8 tubes to play with, I rather leave the 7199's for the Dynaco.
The Bogen amp is model BD-212. I would appreciate a copy of the schematic whenever you have a chance to email it. My email address is salb203 at optonline dot net
Thanks,
Sal Brisindi
Sal Brisindi said:
Sal,
Watcha gonna drive the SE 6V6s with? If you haven't yet decided, think about a 5965.
IMO, tone controls should be COMPLETELY defeatable. Only a few recordings need the help. I'll EMail a Max Robinson designed circuit for the tone control function to you, as the forum software is blocking attachment. Perhaps the moderators will assist me. Use Max's circuit as is or reduce the number of triodes by replacing the cathode followers with DC coupled ZVN0545A source followers, as described in MOSFET Follies.
I'm originally from NJ, Paterson area. Anyway, I'm a ham too and hope to get to a few swap meets this summer.
Just about all the stuff I had to work with lately was off of Ebay. Looks like you got a great bargain there. I like the 6V6 as a nice component (especially 2 in push-pull) for both hi-fi and tube amps, and the 6AQ5 is fairly close as well.
I did get a fixer upper 6V6 PP amp a few months ago (Radio Craftsmen 1948 model), but it cost me over $100, and I had to gut the underside and rewire it as someone screwed it up in the 60's. But I do use it on occasion when I need 2 channels for stuff I need to test out, like my wifes old components we're getting rid of on Ebay, in conjuction with the other new 6V6 amp I built. The only thing is that is has a chrome chassis, and though the sides are perfect, the top is peeling. I think I'm going to remove the tubes, tape over all the sockets and trafos, and grind it down with a wire brush on a drill, then spray on chrome paint from the auto store. Any better ideas?
Just about all the stuff I had to work with lately was off of Ebay. Looks like you got a great bargain there. I like the 6V6 as a nice component (especially 2 in push-pull) for both hi-fi and tube amps, and the 6AQ5 is fairly close as well.
I did get a fixer upper 6V6 PP amp a few months ago (Radio Craftsmen 1948 model), but it cost me over $100, and I had to gut the underside and rewire it as someone screwed it up in the 60's. But I do use it on occasion when I need 2 channels for stuff I need to test out, like my wifes old components we're getting rid of on Ebay, in conjuction with the other new 6V6 amp I built. The only thing is that is has a chrome chassis, and though the sides are perfect, the top is peeling. I think I'm going to remove the tubes, tape over all the sockets and trafos, and grind it down with a wire brush on a drill, then spray on chrome paint from the auto store. Any better ideas?
Eli,
I was going to drive the 6V6's with 12AX7's as I have dozens of them, I can also use 12AU7, 5751, 12AT7 or even 12BH7's I have on hand..
PS: Frank, nice looking amp!
Regards,
Sal Brisindi
I was going to drive the 6V6's with 12AX7's as I have dozens of them, I can also use 12AU7, 5751, 12AT7 or even 12BH7's I have on hand..
PS: Frank, nice looking amp!
Regards,
Sal Brisindi
Sal Brisindi said:
Use the 12AT7 as shown in the El-Cheapo schematic. If you follow the El-Cheapo thread for a bit you'll see why.
The 12AT7 is good in PP amps and wretched in SE amps. The amount of 2nd order HD generated is why.
Low Rp tubes with reasonably high gm make better drivers. The SE trioded 6V6s can be driven by a 12BH7, IF constant current sources (CCS) are used as the plate loads. The idea is to be able to get full power O/P driven directly by a CDP.
5965s are inexpensive. Also, a swap might be arranged (not with me).
Low Rp tubes with reasonably high gm make better drivers. The SE trioded 6V6s can be driven by a 12BH7, IF constant current sources (CCS) are used as the plate loads. The idea is to be able to get full power O/P driven directly by a CDP.
5965s are inexpensive. Also, a swap might be arranged (not with me).
Hi every one!
I'm trying to make sense of the DB212 original schem, but some details of the ground path strategy confuse me. Also I do not understand what's the purpose of keeping some bypass caps been just a fraction of the other channel values (100uF vs 5uF)
I was trying to re draw the power amp section; I'm doingg a mess? or is this right?
I'm trying to make sense of the DB212 original schem, but some details of the ground path strategy confuse me. Also I do not understand what's the purpose of keeping some bypass caps been just a fraction of the other channel values (100uF vs 5uF)
I was trying to re draw the power amp section; I'm doingg a mess? or is this right?
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Sorry,Too late to fix the typos (being/doing) Incidentally I know nothing about this brand and his history, but I'm curious because Bogen amps were mentioned in some passages of Philip K. Dick novels, and it lead me to think they were advanced designs for their time (just a supposition)
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