luvdunhill
Headphoneus Supremus
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someone needs to put a bug in pabbi1's ear about those Amperex "upgrade" tubes
Bijou All Tube Futterman Headphone Amplifier
- Thread starter dBel84
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someone needs to put a bug in pabbi1's ear about those Amperex "upgrade" tubes
pabbi1
Cavalli Audio Spiritual Advisor
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Noooooooooo - my Bijou needs Regal mods first, and the cathode resistor is NOT socketed, so that is the last thing I need to do - modding a working amp.
Besides, Raven is being biased as we speak, and I have been buying 307a, 7w7, and 5v4 (along with a couple of pairs ov 83 and 866a), so the Bijou is staying exactly as it is - unless someone else wants to mod it, or, it gets a new home.
Besides, Raven is being biased as we speak, and I have been buying 307a, 7w7, and 5v4 (along with a couple of pairs ov 83 and 866a), so the Bijou is staying exactly as it is - unless someone else wants to mod it, or, it gets a new home.
balderon
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Quote:
The parts should be delivered Tuesday. I hope it will solve my thermal problem. Thank you for the help.
| Originally Posted by runeight /img/forum/go_quote.gif Yes, you can use the bigger transformer without changing the op points for the mosfets. However, watch out for the heater voltage. The bigger transformer probably has a large current heater winding. Since it will be more lightly loaded it will have a higher voltage. |
The parts should be delivered Tuesday. I hope it will solve my thermal problem. Thank you for the help.
jkroon
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Attachment 17356
Here's what I have done so far. Still waiting on the bijou kit. The sides are soft maple, the top and bottom are 1/4" aluminum plate. I brushed the aluminum with a wire wheel, hard to see in the picture. Inspired by Amphead's oak and cocobolo chassis on post #136 of this thread. I know, no points for originality here. But this is the first time I've ever even cut a piece of wood.
Here's what I have done so far. Still waiting on the bijou kit. The sides are soft maple, the top and bottom are 1/4" aluminum plate. I brushed the aluminum with a wire wheel, hard to see in the picture. Inspired by Amphead's oak and cocobolo chassis on post #136 of this thread. I know, no points for originality here. But this is the first time I've ever even cut a piece of wood.
jkroon
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TimJo
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Quote:
Thanks for the tip pabbi!!! I was able to pick up a pair RCA's for $11.50
I also got a pair of Amprex 6dj8's from the same guy for really cheap.
I hope some others were able to score some as well...
| Originally Posted by pabbi1 /img/forum/go_quote.gif just a heads up... There are some smoking deals on ebay at the moment. I have no knowledge nor affiliation with this seller - and have plenty of EZ81 put back - for at least 4x what these auctions might go for. |
Thanks for the tip pabbi!!! I was able to pick up a pair RCA's for $11.50
I also got a pair of Amprex 6dj8's from the same guy for really cheap.
I hope some others were able to score some as well...
emelius
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no balanced super bijou plans yet?...
jkroon
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OK, I got most of my stuff from glassjaraudio.com. I'm still missing the tube sockets and the two pin phoenix connectors. Everything is soldered on the boards except for those two items. While I'm waiting for my parts to arrive I have a question about the voltages. On my transformer I'm getting 300V instead of 260v, and 7.5V instead of 6.3V. The power at the outlet is 120V. The primary of the transformer is 115V. I guess the slightly higher primary voltage (+5V) is the reason for the higher secondary voltages, but will this be OK?
Clutz
Tells us when we're offset.
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You're probably getting 300V instead of 260 and 7.5V instead of 6.3 because the transformer is unloaded.
120 / 115 = 1.043. 300 / 260 = 1.15, 7.5 / 6.3 = 1.19.
So, the extra five volts of input is about 4.3% higher than expected, but the output voltages are 15 and 19% higher.
It's because the transformers are unloaded.
120 / 115 = 1.043. 300 / 260 = 1.15, 7.5 / 6.3 = 1.19.
So, the extra five volts of input is about 4.3% higher than expected, but the output voltages are 15 and 19% higher.
It's because the transformers are unloaded.
balderon
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Quote:
As expected changing to the 270FX worked out very well. The tranfo barely warm and the B+ is at spec with plenty of power to spare (even after drawing the additional 20ma). The heater voltage increased to only 6.5v.
| Originally Posted by runeight /img/forum/go_quote.gif Yes, you can use the bigger transformer without changing the op points for the mosfets. However, watch out for the heater voltage. The bigger transformer probably has a large current heater winding. Since it will be more lightly loaded it will have a higher voltage. |
As expected changing to the 270FX worked out very well. The tranfo barely warm and the B+ is at spec with plenty of power to spare (even after drawing the additional 20ma). The heater voltage increased to only 6.5v.
pabbi1
Cavalli Audio Spiritual Advisor
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Quote:
My balanced Bijou sounds pretty super with the hd800...
| Originally Posted by emelius /img/forum/go_quote.gif no balanced super bijou plans yet?... |
My balanced Bijou sounds pretty super with the hd800...
bhjazz
Headphoneus Supremus
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Quote:
The Super Bijou is listed at Cavalliaudio as "in the works." We'll see what lies ahead, but I'll bet Alex has something cool up his sleeve.
1300
| Originally Posted by emelius /img/forum/go_quote.gif no balanced super bijou plans yet?... |
The Super Bijou is listed at Cavalliaudio as "in the works." We'll see what lies ahead, but I'll bet Alex has something cool up his sleeve.
1300
TimJo
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bhjazz
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Quote:
Nice catch! I completely forgot about that little post. Thank you TJ!
| Originally Posted by TimJo /img/forum/go_quote.gif He gave us a preview a few months back.... 
Bijou II |
Nice catch! I completely forgot about that little post. Thank you TJ!
mugdecoffee
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I just made a szekeres amp/buffer and was thinking about adding it as an active ground channel to my bijou amp. Is there anything wrong with this? For wiring I'm thinking input ground->buffer input and power from a regulated 12v grounded to start ground. Does that make sense?
Should the active ground improve the sound somewhat? Is there any disadvantage to using a solid state ground buffer or one of a different design than the rest of the amp? Am I missing something?
Also, it be too much to ask of the 270dax to get the 12v supply from the two heater windings in parrallel, no?
Should the active ground improve the sound somewhat? Is there any disadvantage to using a solid state ground buffer or one of a different design than the rest of the amp? Am I missing something?
Also, it be too much to ask of the 270dax to get the 12v supply from the two heater windings in parrallel, no?
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