Turns out my Fleetwoods differ slightly. The biggest difference is that one has way bigger OPTs -- and a bit of weird circuitry on the input of the power tube. The one with the smaller OPTs -- still substantial for 50EH5s -- is a Baycrest. This one has the same OPTs as Giovani's.
The amp is actually Japanese, and much more neatly constructed than the typical North American or German units.
dave
The amp is actually Japanese, and much more neatly constructed than the typical North American or German units.
dave
Attachments
And here is the minimalist design i'm hoping to get away with... no grid stopper, wired in triode (lower power, lower output resisitance), no cathode bypass (some degeneration, higher output resistance). If i can get away with it, then the only cap in the signal path is the last power supply cap.,,, with only a requirement for 200V i can put a nice poly there.
dave
dave
Attachments
planet10 said:
This looks great. I'd be willing to try this out too. When you say poly, are you talking polypropylene or is polyester good too?
Is that 6CA4 tube of any use in a power supply.
I am also interested in a preamp. Can the ECL86 tubes be used for that?
Cheers,
Gio.
GG said:
In general polypropylene is better.... If i don't have something suitable in my collection, i'll probably just get a Solen.
Yes... we have been having good results with EZ81 -- been using them in hybrid bridges to replace SS bridges,
There is a thread somewhere here on this forum about just such a beast.
dave
They Work
Just for fun, I decided to power up the two old consoles. A little to my suprise, they still worked! Some of the capacitors must be dead as you get clicks and pops. I did get a kick playing an mp3 player through them. The radio sounds very good!
Other than the audio tubes and iron, what is worth salvaging off of these consoles? Are the radio tubes worthwhile to hang on to? I imagine the electrolytic caps will be close to dead. Are the carbon comp. resitsors worthwhile to pull, they are mostly silver tolerance?
These capacitors caught my attention .. they look like some sort of poly.
Gio.
Just for fun, I decided to power up the two old consoles. A little to my suprise, they still worked! Some of the capacitors must be dead as you get clicks and pops. I did get a kick playing an mp3 player through them. The radio sounds very good!
Other than the audio tubes and iron, what is worth salvaging off of these consoles? Are the radio tubes worthwhile to hang on to? I imagine the electrolytic caps will be close to dead. Are the carbon comp. resitsors worthwhile to pull, they are mostly silver tolerance?
These capacitors caught my attention .. they look like some sort of poly.
Gio.
Attachments
Re: They Work
You never know... i save everything i can strip out that isn't obviously pooched... i'm often surprised at what is useful (or saleable).... pull those drivers -- even if it is only for me to see a pic 🙂
dave
GG said:
You never know... i save everything i can strip out that isn't obviously pooched... i'm often surprised at what is useful (or saleable).... pull those drivers -- even if it is only for me to see a pic 🙂
dave
Hi Dave,
Any thoughts on those capacitors? The outside feels like ceramic?
Sorry, with only one good driver I did not bother pull the speakers. I will take pictures next time.
I think I may go hunting for more consoles this weekend. I'd still like to get some more parts for a phono amp as I am not sure about an ECL86 phono amp. Do these consoles ever contain any sizeable chokes?
As for the 50EH5 tubes, I'd like to try a small wattage amp which I would use for the office since I have to play music very quietly.
I have been playing around with PSU Designer II...very nice, I can't wait to build a powersupply using an EZ81. Is there something similar available that would help me design an amp or preamp?
Regards,
Gio.
Any thoughts on those capacitors? The outside feels like ceramic?
Sorry, with only one good driver I did not bother pull the speakers. I will take pictures next time.
I think I may go hunting for more consoles this weekend. I'd still like to get some more parts for a phono amp as I am not sure about an ECL86 phono amp. Do these consoles ever contain any sizeable chokes?
As for the 50EH5 tubes, I'd like to try a small wattage amp which I would use for the office since I have to play music very quietly.
I have been playing around with PSU Designer II...very nice, I can't wait to build a powersupply using an EZ81. Is there something similar available that would help me design an amp or preamp?
Regards,
Gio.
GG said:
I'm not quite sure what those are... Aerovox is a good brand name thou.
I don't think i've ever seen a choke in a console hifi.... organs thou are often quite rich for power supply bits.
dave
GG said:
I took a look at SPICE, but it looks too complicated. Can someone suggest any other tube design software? Is TubeCAD the only other choice? The price sure looks ok if it does what it claims to do.
Regards,
Gio.
Another Console
I have come across another console. This one from a buddies grandma.
Philips console, tube compliment, EZ81, 2X ECL86 and 2X 12AX7.
The 12AX7 are marked Rogers, Made in Holland
The ECL86 are GE, made in Japan
The EZ81 marked Rogers, made in Great Britan.
The power iron is very large. The OP transformers are much bigger (twice the size) of the previous ECL86 OPT that I pulled.
The console had 4 ~6.5" alnico, all paper, full range speakers. The motor is small and the frame is light. However, they are in great condition for their age, but I do not find them too exciting.
This time I took pictures! 🙂
planet10 said:
I have come across another console. This one from a buddies grandma.
Philips console, tube compliment, EZ81, 2X ECL86 and 2X 12AX7.
The 12AX7 are marked Rogers, Made in Holland
The ECL86 are GE, made in Japan
The EZ81 marked Rogers, made in Great Britan.
The power iron is very large. The OP transformers are much bigger (twice the size) of the previous ECL86 OPT that I pulled.
The console had 4 ~6.5" alnico, all paper, full range speakers. The motor is small and the frame is light. However, they are in great condition for their age, but I do not find them too exciting.
This time I took pictures! 🙂
Attachments
Re: Another Console
Philips, made in the same factory as Miniwatts & Valvos -- quite good as far as 12AX7s go.
Those likely aren't original
Mullard (ie Philips but made in England)
Very likely Hammond iron -- you have the bits there for a nice little SE amp (either reuse the ECL86 or go to EL84)
Don't let the tiny magnets fool you, those are quite sought after for open baffles...
I just scored a relative of your console -- similar Philips speakers (different basket, otherwise quite close), not as many ECC83, and the ECL86s were the original Rogers labeled Mullards.
Because of import duties, some parts were shipped from Europe and the units were assembed in Canada with a certain amount of Canadian content.
dave
GG said:
Philips, made in the same factory as Miniwatts & Valvos -- quite good as far as 12AX7s go.
Those likely aren't original
Mullard (ie Philips but made in England)
Very likely Hammond iron -- you have the bits there for a nice little SE amp (either reuse the ECL86 or go to EL84)
Don't let the tiny magnets fool you, those are quite sought after for open baffles...
I just scored a relative of your console -- similar Philips speakers (different basket, otherwise quite close), not as many ECC83, and the ECL86s were the original Rogers labeled Mullards.
Because of import duties, some parts were shipped from Europe and the units were assembed in Canada with a certain amount of Canadian content.
dave
Re: Re: Another Console
Yeah, the OPTs on this console are respectible, so I will try an SE amp. I also want to try a simple 12AX7 phono preamp.
Is there a way to measure the OPT to determine if it is also suitable for an EL84?
Gio.
planet10 said:
Yeah, the OPTs on this console are respectible, so I will try an SE amp. I also want to try a simple 12AX7 phono preamp.
Is there a way to measure the OPT to determine if it is also suitable for an EL84?
Gio.
Re: Re: Re: Another Console
An ECL86 can generally be considered half of a 12AX7 & an EL84 in the same bottle (a bit less dissapation than an EL84) and uses the same range of OPTs as an EL84 -- given the economics of manufacturing, it is likely that the same OPT was also used for EL84/6V6/6AQ5 applications.
To measure the turns ratio, i connect my Variac to the primary (set to 10V) and then measure the secondary. Divide 10V by the measured voltage on the seconday and square it... that is your turns ratio. Multiply that by the nominal impedance of your speakers and you have the reflected impedance of the OPT. For an EL84, 5-8K is typical.
An example can be seen here (my guess is that these OPTs are similar to yours)
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=5764712827
dave
GG said:
An ECL86 can generally be considered half of a 12AX7 & an EL84 in the same bottle (a bit less dissapation than an EL84) and uses the same range of OPTs as an EL84 -- given the economics of manufacturing, it is likely that the same OPT was also used for EL84/6V6/6AQ5 applications.
To measure the turns ratio, i connect my Variac to the primary (set to 10V) and then measure the secondary. Divide 10V by the measured voltage on the seconday and square it... that is your turns ratio. Multiply that by the nominal impedance of your speakers and you have the reflected impedance of the OPT. For an EL84, 5-8K is typical.
An example can be seen here (my guess is that these OPTs are similar to yours)
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=5764712827
dave
timely thread!
I picked up an EL84 SE console last weekend. the name on the brass plate says Stereophonic by Century.
I have cleaned it up and slowly brought it up on a varaic.
I connected a CD player to the amp section and it worked!
Tubes for the amp include:
2 GE el84/6BQ5
2 GE 12ax7
1 Amperex "Buggle Boy" EZ81/6ac4
AM/FM section tubes includes 2 12at7 (plus 3 6BA6, 6AU6A, 6BE6, 6AL5 7 pinners). ALL GEs.
I don't know who mades the iron but the audio transformer has the number TA-8006-606-2-47. It looks like the Hammond iron on the ebay link above.
I did trace out the schematic but basically it is:
input -> volume -> 12ax7 -> bass/treble -> 12ax7 -> balance -> el84 -> output transformer.
The plan is to build Alex's EL84 amp (see: this DIYAudio Thread )
This design uses 1/2 of a 12at7 plus an el84 per per channel. I now have these tubes and a PS 🙂.
The console enclosure was a mess so I junked it.
I think consoles are great sources of tube parts and allow DIY guys get a taste for different tubes and designs.
rick
I picked up an EL84 SE console last weekend. the name on the brass plate says Stereophonic by Century.
I have cleaned it up and slowly brought it up on a varaic.
I connected a CD player to the amp section and it worked!
Tubes for the amp include:
2 GE el84/6BQ5
2 GE 12ax7
1 Amperex "Buggle Boy" EZ81/6ac4
AM/FM section tubes includes 2 12at7 (plus 3 6BA6, 6AU6A, 6BE6, 6AL5 7 pinners). ALL GEs.
I don't know who mades the iron but the audio transformer has the number TA-8006-606-2-47. It looks like the Hammond iron on the ebay link above.
I did trace out the schematic but basically it is:
input -> volume -> 12ax7 -> bass/treble -> 12ax7 -> balance -> el84 -> output transformer.
The plan is to build Alex's EL84 amp (see: this DIYAudio Thread )
This design uses 1/2 of a 12at7 plus an el84 per per channel. I now have these tubes and a PS 🙂.
The console enclosure was a mess so I junked it.
I think consoles are great sources of tube parts and allow DIY guys get a taste for different tubes and designs.
rick
I kept the speakers. I wired them to the output transfomers when I brought the amp up. Each channel includes a 8" woofer and two 3" tweeters in parallel and a 6uF 'crossover'.
No foam rot like some other speakers I've seen! I was going to throw them away but after reading a bit more, I may try to use them. Gee-tar cabinet?
rick
No foam rot like some other speakers I've seen! I was going to throw them away but after reading a bit more, I may try to use them. Gee-tar cabinet?
rick
Any chance you can take pics?
Try throwing the 8s on a baffle (even just a big piece of cardboard... you might be surprised 🙂
dave
Try throwing the 8s on a baffle (even just a big piece of cardboard... you might be surprised 🙂
dave
- Status
- Not open for further replies.