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Post by dean0 on Nov 26, 2009 17:27:14 GMT
New amp build ;D Need some confirmation before I wire up the trafo. Im using the Hammond 370FX. For UK voltage, what should I use on primary 220vac or 240vac, does it matter? For 240vac; -Connect Brown to Black -Blue (Active) -White (Neutral) Look okay? Info from here; www.hammondmfg.com/300series.htmps Can the Chassis Earth from the IEC connector be connected to the star Ground? Thanks
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Deleted
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Post by Deleted on Nov 26, 2009 20:25:16 GMT
Dean Use 240V not 220V. U.K. like Australia now has the 230V standard,which means it is permitted to go as high as 253V. Using the 220V setting, if you are in an area where the voltage is more likely 240V may cause excessive output voltage from the transformer. You should be able to connect IEC earth to star ground, but personally, I would connect it to just the metalwork where the transformer is mounted , or aa mounting scew of the transformer if it is not a toroidal type.and perhaps the front panel if it is metal. You can always connect the 2 together if there are hum problems. SandyK
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Post by dean0 on Nov 30, 2009 16:26:31 GMT
My build is coming along nicely, just waiting for front/top panels to be done and then I will wire it all up. Can someone double check my wiring so far, I have the primary configured for 240VAC input Hammond 370FX trafo ( Hammond Mfg. - Universal Primary - "Classic" Power Transformers) Primaries; (240VAC) BROWN / BLACK - Tied together BLUE - Live White - Neutral Thanks
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Post by dean0 on Dec 1, 2009 17:51:11 GMT
maybe a future 'upgrade'... they sure do look pretty!
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Post by dean0 on Dec 2, 2009 16:26:25 GMT
Power supply tested, left on for a couple of hours no problems, had to adjust the voltage 3 times to keep it at 250v. Still waiting on panels before I go ahead and hook the rest up, more pic's later this week, I hope...
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Post by PinkFloyd on Dec 2, 2009 19:10:32 GMT
You're making a nice job of things Dean! Keep the pictures coming mate
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Post by dean0 on Dec 2, 2009 20:03:03 GMT
You're making a nice job of things Dean! Keep the pictures coming mate thanks, will do
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Post by dean0 on Dec 16, 2009 18:36:17 GMT
Finished my build but I have hum/buzz problem. With nothing connected, I can turn volume 20% with no noise then I get hum/buzz. If I touch starground and my volume knob the hum does decrease a little, also tried moving some wires with no success. When my DAC is connected the hum/buzz is worse, but music plays fine. Iam not using the NFB atm, and remove R12, and replaced R1 with 300ohm. Voltages both measure a constant 250v on both boards. Iam thinking that connecting starground to volume pot, and Amphead's Heater Mods may help, any ideas or input would be much appreciated. More info here; www.cavalliaudio.com/bijou/main.php?page=overview
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Post by dean0 on Dec 16, 2009 19:23:07 GMT
okay, I seem to have solved one issue of noise when the DAC is not connected, running a peice of wire from the starground to the chassis got rid of noise, only on full volume their is a slight hum, bearly audioble. But when the DAC is connected Iam still getting noise, alot less than before but it is there. Iam using Gamma y2 DAC powered by usb and feed via Optical from my soundcard. When I unplug the usb power source the noise goes, does that mean using a different 5v external powersupply would eliminate the problem? Is their any negetive effects on SQ using Amphead's Heater Mods, I may do this mod to see what kind of effects it has.
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Deleted
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Post by Deleted on Dec 16, 2009 20:17:49 GMT
dean0
I always earth the shaft of the volume control to the main earth. I usually use something like the earth tag (large outer ring) from a recovered old large RCA socket.If need be, to make it a little larger, I snip through the side opposite the solder tag and spread it open a little. SandyK
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Post by dean0 on Dec 16, 2009 20:46:27 GMT
Nice idea, hopefully I'll have time tommorow to sort these hum issues, and other mods Ive stopped working on the amp for tonight, and just enjoying the music regardless of the hum. I have to say this amp sounds beatiful, the pairing with my HD650's is a match made in heaven, smooth mids, rich inviting sound and very musical. Iam not the best at describing what I hear... but this is the best I have ever heard, Iam listening to some Peter Green atm and loving it, his guitar never sounded so good! I'll update more and take finished pics when I have sorted these issues, back to the music!
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Post by dean0 on Dec 17, 2009 16:07:12 GMT
quick update, I connected the starground to the chassis and also iec, and the the buzz/hum has been almost eradicated, you can bearley hear it only over 50% volume, also my B+ went up from 249v to 254v. I have trimmed it down and is now constant 250v accross all boards. But there is still a very faint hum which I would like to resolve. Moving wiring has no effect, Iam thinking Amphead's Heater Mod may be my next option. [/url]
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Deleted
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Post by Deleted on Dec 18, 2009 7:30:52 GMT
Miguel The answer to your question is here : www.cavalliaudio.com/bijou/main.php?page=ampschematicHalf a 6922 provides gain, and feeds the other half of the 6922 which is used as a phase splitter to drive both halves of an ECC99 in push pull. Both valves are twin triodes. Alex
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Post by dean0 on Dec 18, 2009 18:20:08 GMT
the boards and parts are relativley cheap, the expensive part is the trafo and case (depending on what you use). BTW I have some Amperex 6DJ8 Bugle Boy and EZ81 valves on the way! ;D
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Post by dean0 on Jan 6, 2010 20:31:27 GMT
Valves arrived from Holland Still waiting on Vish-Dale 23 Stepped Attenuator, and resistors for the Regals Mods. More Pics and impression once its all fitted. edit. what is a good technique to clean valve pins?
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Post by dean0 on Jan 20, 2010 18:24:36 GMT
Update; - Bugle Boy 6DJ8 Valves - EZ81 P/S - Regal Mods - 100k Stepped Attenuator
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Will
Been here a while!
Ribena abuser!
Member since 2008
Posts: 2,164
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Post by Will on Jan 31, 2010 12:15:45 GMT
How are things going with the Bijou, Dean?
Also, where'd you get the Hammond traffo from?
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Post by dean0 on Jan 31, 2010 13:05:06 GMT
Going great, this Amp and HD650's is amazing, the difference between the Bijou and SCHA is mind blowing, seriously! But as others have mentioned on head-fi this amp is not so good with low impendance 'phones, like Superlux HD681, which is a shame... The Hammond Traffo is from here; www.tube-town.net/ttstore/index.php/cat/c155_300-Series-Classic-Tube.htmlGood price's, cheapest I could find.
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Post by dean0 on Feb 28, 2010 18:51:09 GMT
More update's - Rewiring the power/heater wiring with 18awg Silver Plated Teflon wire, the stuff I was using was 22awg. - Shielded Input/Output Wire. - Replaced coupling/output caps with M-Caps. - Goldpin ECC99 Valves. I will post more pics/impressions once I have wired it all up.
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Z
Fully Modded
Posts: 3,391
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Post by Z on Mar 26, 2010 16:56:59 GMT
is this thing really that dangerous to build? there's a disclaimer on the glass jar site.
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Post by dean0 on Mar 26, 2010 17:39:21 GMT
This was my first 'high voltage' build, as long as you read and double check everything (and posting pictures if unsure), you should be okay. It went together very smoothly thanks to all the info/threads on this amp. What headphones would you be driving?
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Z
Fully Modded
Posts: 3,391
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Post by Z on Mar 26, 2010 18:11:14 GMT
hopefully some dt150's 250ohm in the future. right now some dt770 80ohm and futuresonic atrios (i had merely lost them ). i was wondering about the mods and if they are worth it. i looked up the regal mod and it said something about 10mw into the tubes being better than 3mw. what's all that about? is it worth the money?
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Post by dean0 on Mar 26, 2010 18:29:04 GMT
Yes, the mods involve changing some resistors (costs nothing), so it is better to perform the mods when building from scratch. After the mods the amp sounds more foward and 'aggresive', which compliments the already laid back tube sound when stock. I would also recomend the Hammond 370FX, if performing the mods. The best tube combination IMO is 6DJ8 Bugle Boy 1960 & ECC99, you will also need the EZ81 for Regal Mods. If you are using low/high Impedance headphones you will need the NFB, or bypass it if using just High Impedance Headphones. ps You joined in March 2010 and over 1000 posts!
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Z
Fully Modded
Posts: 3,391
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Post by Z on Mar 26, 2010 18:33:51 GMT
yeah, i'm hot shit you know.
so it would probably be better to just buy all the parts separate and not a kit?
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Post by dean0 on Mar 26, 2010 18:41:35 GMT
Yes, if you are doing the mods, you can change the film caps/tubes to your own liking.
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