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Bijou All Tube Futterman Headphone Amplifier - Page 140

post #2086 of 3981
12/19/08 at 8:41pm
Fishski, sorry to hear about that. I think this is one for the man himself. Runeight? Edit: hey Fishski, I know how you can find it. With the amp powered down and safely discharged, ohm out the boards looking for differences between the working channel and the one not working.Thinking like a mirror image of one another. Otherwise I would start by replacing regulators in the bad channel and the EZ81. I have a funny feeling about the add-on board however, but mostly because I don't know what its doing.
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post #2087 of 3981
12/19/08 at 9:12pm
fishski, let's start from scratch to try to solve this. As an aside, it could be a delayed result of the earlier problem where you had arcing in the rectifiers (if indeed these are the same tubes).

First thing, disconnect the transformer from the PS board (all leads). Do you still have continuity between any of the windings?
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post #2088 of 3981
12/19/08 at 10:23pm
Quote:
Originally Posted by regal View Post
Can I sub a 6H30 in the input without adding a separate heater transformer or is the 270DAX good enough. The reason I ask is that I haven't known Hammond to even be remotely close to their heater specs. They're usually significantly under rated.
Sorry I hadn't got back to you sooner... yes I have an extra transformer for the heaters.. I think it's an:

166K6 7.56 115V 60 Hz. 6.3 C.T. 1.2 C6H

if I remember right.

I would love for someone to show me something better (single ended wise) than my version of the Bijou with my DDDAC dac (maybe Ferrari's?) . I'm not trying to be cocky... I really want someone to show me something better or any kind of improvement over what I currently have...

I am so happy with this set up that one day I envision a balanced version of this (when finances can support it)...

Alex is the best...in case you haven't figured that out. No one else supports you like he does...

Actually, I'd like to hear what the fuss about Senn's is all about..cause I really like my Grado's.
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post #2089 of 3981
12/19/08 at 10:35pm
sorry to hear as well fishski. To throw one possibility into the pool of answers... my ez81 was arcing internally and blowing fuses left and right. I replaced it and have been operating just fine for 500+ hours. Seems to have been a fluke or a bad tube. GL tracing the problem.
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post #2090 of 3981
12/19/08 at 11:04pm
Quote:
Originally Posted by runeight View Post
fishski, let's start from scratch to try to solve this. As an aside, it could be a delayed result of the earlier problem where you had arcing in the rectifiers (if indeed these are the same tubes).

First thing, disconnect the transformer from the PS board (all leads). Do you still have continuity between any of the windings?
i was wondering about the abuse the EZ81 took the first time around with the PS add-on. i don't remember if i replaced it or not. i do have another EZ81, new or abused, i don't know.

i'm at work right now until 8 am tomorrow. i'll have some time to test the windings before bed and report my findings.

thanks for everyones help.
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post #2091 of 3981
12/19/08 at 11:46pm
Quote:
Originally Posted by huskydawg9 View Post
Actually, I'd like to hear what the fuss about Senn's is all about..cause I really like my Grado's.
the K701 sound outfreakin'standing, even without NFB. to my ears, no trouble driving lower impedances in my build, so i would guess that the Bijou could drive Grado proper. i kind of wish i still had my sr-225 now.
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post #2092 of 3981
12/20/08 at 11:24am
with the transfo removed from the offending PS, i have continuity between all secondaries. the foul smell seems to be coming from this transfo as well. like i said before, it got really hot. i can only assume the worst ...
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post #2093 of 3981
12/20/08 at 11:32am
I'm sorry fishski, but that transformer is a goner. It's hard to damage a transformer unless there is a dead short somewhere. Are you going to replace it? If so, we'll try to debug the rest of the PS when you're ready.
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post #2094 of 3981
12/20/08 at 12:12pm
Quote:
Originally Posted by runeight View Post
I'm sorry fishski, but that transformer is a goner. It's hard to damage a transformer unless there is a dead short somewhere. Are you going to replace it? If so, we'll try to debug the rest of the PS when you're ready.
i'll wire up the other half of the amp unbalanced for comparison before deciding to shell out for another transfo. while i heard a definite improvement going from unbalanced to balanced, i also replaced the cheap RS pot with my attenuators at that time. we'll see how she sounds unbalanced with the new attenuator.

i hope my K701s are still functional. they were plugged in the first time i blew a fuse. i think it was the second time i blew a fuse that the transfo died.

thanks once again. i think i need a drink...
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post #2095 of 3981
12/20/08 at 10:10pm
Yeah, I hope the phones are OK. You can ohm them out for continuity, eventhough that won't tell you much. Your build looked impeccable, so I'm leaning towards the bad EZ81 as the source of the problem. Too bad it had to take out the trafo, if thats the case. If you rebuild the other channel, you want to make sure that you don't measure low resistance on the output of that channel's PS before powering up. You would want to gingerly try a power-up with fast-blo 1 amp, then fast-blo 1.5 amp and then regular 1 amp fuses on hand, just in case. And maybe 1.5 amp regular fuse depending on how it goes. And your sacrificial phones to start. Quick trigger finger on the power button. But if you want to wait awhile before going balanced again, thats good too. The offer stands as I mentioned before, but you have proven yourself a quite capable builder already. ;-)
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post #2096 of 3981
12/21/08 at 3:10am
Quote:
Originally Posted by amphead View Post
Yeah, I hope the phones are OK. You can ohm them out for continuity, eventhough that won't tell you much. Your build looked impeccable, so I'm leaning towards the bad EZ81 as the source of the problem. Too bad it had to take out the trafo, if thats the case. If you rebuild the other channel, you want to make sure that you don't measure low resistance on the output of that channel's PS before powering up. You would want to gingerly try a power-up with fast-blo 1 amp, then fast-blo 1.5 amp and then regular 1 amp fuses on hand, just in case. And maybe 1.5 amp regular fuse depending on how it goes. And your sacrificial phones to start. Quick trigger finger on the power button. But if you want to wait awhile before going balanced again, thats good too. The offer stands as I mentioned before, but you have proven yourself a quite capable builder already. ;-)
thanks for the re-offer . some good news at least - i've rewired for unbalanced and everthing sounds good, including the K701.

i think i'll hang here for awhile and wait for my Vishay attenuator resistors and silver signal wire before i make any decisions. i'd like to spend some time unbalanced with a decent attenuator in place. right now, i'm considering my option$ on a different, smaller chassis for unbalanced just in case i decide to leave it unbalanced.

btw, i left the PS multiplier mod in place on the working PS. i'm a bit too deflated to try Regals mod right now, but will probably try it down the road - especially if i end up ripping the boards out for a re-chassis.
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post #2097 of 3981
12/21/08 at 10:36pm
Here is the chassis with 4 sides for the balanced version, I'll get a bottom cut tomorrow.

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post #2098 of 3981
12/21/08 at 11:52pm
How are you cutting the aluminum? Just curious as I am taking on some other casework - looks like you are using solid bar to join the sides?
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post #2099 of 3981
12/22/08 at 2:49am
The aluminum, is scrap from a surplus metals store. The front and rear panel were the size that they are when I bought them. The side panels were cut on an industrial hydraulic shear, at the scrap metal store. And the corners are bolted with 1/4 inch aluminum square stock that I hacksawed to size, with quality stainless hardware. It's important to use a punch to mark the drill hole or the holes won't look properly centered. If you have access to a metal blade bandsaw and use a guide, you could get good results Pabbi.
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post #2100 of 3981
12/22/08 at 6:42pm
So, I Regal-modded my Bijou this afternoon... this thing is unreal! Cymbals, drums, synth, piano, and vocals all come alive. I never knew what this amp was capable of before, but I'm glad I took time out of my B22 build for this.

Can anyone compare 6N1P to a decent pair (NOS, gold pins) of 6922s? I socketed the cathode resistor while I was in there today and I'm debating picking up some 6N1P-EV.
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