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Post by PinkFloyd on Dec 15, 2007 8:01:13 GMT
I don't really want tat but something thats going to be worth while building What about this? beautiful PCB (top quality) this is really gonna be FUN to build and, Sandy, it's a hybrid......... YES it has "valves"...... ooh pretty glowing thingies...... IMO looks like it's worthwhile building Leo....... the PCB itself is top quality and just crying out "populate me with parts"... looks good
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Post by Deleted on Dec 15, 2007 9:33:50 GMT
"Sandy, it's a hybrid......... YES it has "valves"...... " Excuse me while I regurgitate !
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leo
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Post by leo on Dec 15, 2007 13:39:18 GMT
I did build the Millet Hybrid, the version before the millet max, I also tried out the optional discrete buffer
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Post by leo on Dec 15, 2007 13:52:52 GMT
Be interesting to see what you think of the Max version Mike, especially how it compares against the X-cans
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mrarroyo
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Post by mrarroyo on Dec 15, 2007 14:17:31 GMT
Leo, what do you think of the sound from the Millet Hybrid you built? Did you use boutique parts?
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Post by leo on Dec 15, 2007 16:33:25 GMT
Leo, what do you think of the sound from the Millet Hybrid you built? Did you use boutique parts? Its an amp that has its followers and proving quite popular, I found it smooth with a wide sound stage, not as accurate as I'd have liked but certainly not bad. The optional discrete buffer was a worthwhile upgrade improving bass I tried various caps in it, Panasonic FC,BG N types and Silmics with Multicap RTX and Auricaps for the lower value films, also tried a couple of different tubes GEC and RCA All resistors was Dale RN60's, regulation was from ALW super regs, diodes was MUR860 and transformer was a frame E/I core. After I'd finished playing about with it I gave it away to a friend who loved it
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Post by mrarroyo on Dec 15, 2007 19:15:30 GMT
Lucky friend!
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Post by jelosno on Dec 17, 2007 0:49:10 GMT
If you use Polycarbonate instead of Perspex it would be very hard to scratch it. The stuff comes under many different names. Bayer calls theirs MACROLON. I use them in UV resistant form as headlight covers for 4x4s and motorbikes. Have saved me some money already. Cutoffs I use to direct/channel airflow in my PCs so they can run with less fans = quieter. Polycarb is easy to work with. Stefan PS just found this: www.omnexus.com/tc/Polycarbonate/index.aspx
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FritzS
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Post by FritzS on Dec 17, 2007 3:45:26 GMT
Sandy - why?
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Post by Deleted on Dec 17, 2007 4:39:06 GMT
Excuse me while I regurgitate ! "Sandy - why?" Fritz This amplifier needs very close matching of transistors to achieve good results . Good,not great . As for using car radio type valves with very low HT, and LOW performance, or for that matter, any valves, is a retrograde step. This design has been more cobbled together to show that the combination is feasible for ADVANCED constructors. The performance figures don't appear to be readily obvious either. I was forced to adapt to technology in my 44 year employment in Telecommunications with Australia's Telstra. It is not as if I haven't grown up with valve technology and experienced it first hand. I have. And despite the early generations of semiconductor amplification sounding horrendous, semiconductor technology has long since eclipsed the performance of valve technology in every aspect, except for the rosy feeling that valves give to many people who want to stay comfortably living in the past. I am not saying that valve technology can't be made to perform very well indeed overall, but that the cost of valve amplification with such qualities comes at a cost that is prohibitive to most people. Greenhouse gases friendly ? No way ! No wonder Graham felt that his seeds had fallen on barren soil ! SandyK I better watch out that I don't get savaged by a pack of Pitbull terriers !
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Post by FritzS on Dec 17, 2007 8:39:32 GMT
Excuse me while I regurgitate ! Fritz This amplifier needs very close matching of transistors to achieve good results . Good,not great . As for using car radio type valves with very low HT, and LOW performance, or for that matter, any valves, is a retrograde step. This design has been more cobbled together to show that the combination is feasible for ADVANCED constructors. The performance figures don't appear to be readily obvious either. I was forced to adapt to technology in my 44 year employment in Telecommunications with Australia's Telstra. It is not as if I haven't grown up with valve technology and experienced it first hand. I have. And despite the early generations of semiconductor amplification sounding horrendous, semiconductor technology has long since eclipsed the performance of valve technology in every aspect, except for the rosy feeling that valves give to many people who want to stay comfortably living in the past. I am not saying that valve technology can't be made to perform very well indeed overall, but that the cost of valve amplification with such qualities comes at a cost that is prohibitive to most people. Greenhouse gases friendly ? No way ! No wonder Graham felt that his seeds had fallen on barren soil ! SandyK Sandy, in my youth I handicrafts with tubes - some RF and audio with D.. tubes - and had an Heathkit amp 2x 8W, 4x ECL86 I think a ECC88, E88CC, 6922, 6DJ8 or substitudes does this job better, and I had seen a amp like Millet Hybrid with this, but I forget where This worthwhile information I found today: Bauanleitung für einen Invers Futtermann OTL mit ECC88 - von Mario Benndorfwww.jogis-roehrenbude.de/Leserbriefe/Benndorf-KH/Benndorf-KH.htmwww.jogis-roehrenbude.de/Leserbriefe/Benndorf-KH/Benndorf-KH.gifPCL 805 - Röhren-Kopfhörerverstärker - von Helmut Beckerwww.jogis-roehrenbude.de/Verstaerker/PCL805-KH-Amp/PCL805-KH.htmmore about tubes:www.jogis-roehrenbude.de/Roehren-Geschichtliches/ECC88-Familie/ECC88-Familie.htmwww.krauhs.net/documents/ecc88_e88cc_6922.htmlwww.duncanamps.com/
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Post by Deleted on Dec 17, 2007 9:24:48 GMT
Friedrich I played with valves in all different kinds of gear as a hobby, and also in Telecommunications equipment ,and program line amplifiers and monitor amplifiers for around 25 years. A friend and myself also used to go to all the local HI-FI shows as well as an Interstate trip to Melbourne for one HI-FI show, so we had plenty of opportunities to compare valve and solid state gear. I just firmly believe that valve based amplification has much greater limitations than properly designed solid state gear. However, that doesn't mean that I will not try to offer advice when the occasion arises regarding valved equipment, if I feel that I am able to help. BTW, I have also given up on amplifiers using FETs in the output stage. I have been there , done that, as a posted photo of a still working MOSFET amplifier that I made almost 30 years ago, will testify. Alex
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Post by leo on Dec 17, 2007 11:11:52 GMT
Its not just me who finds mosfets sound smooth and artificial then same with discrete J-fets Thing I don't understand is why 80% of these tube headphone amps only use 20 odd volts of HT feeding the anodes of the likes of ECC88 when this type of tube sounds better with higher HT
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Post by FritzS on Dec 17, 2007 11:18:23 GMT
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Post by Deleted on Dec 17, 2007 11:26:07 GMT
"Thing I don't understand is why 80% of these tube headphone amps only use 20 odd volts of HT feeding the anodes of the likes of ECC88 when this type of tube sounds better with higher HT " Leo Because they have never seen a copy of the old Radiotron designer's handbook ? Seriously, these valves perform much better with correct HT voltages. Haven't these guys heard of cathode poisoning ? Alex
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Post by FritzS on Dec 17, 2007 13:08:24 GMT
Alex - you have right The most of the amps from my links use 200 V or more. Of all the tube amp schemas I had seen - the basic design can reduce to some few and the most are old knowledge. I have two old electronic engineer textbooks from 1948/49 - amazing what you can all see here
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Post by leo on Dec 17, 2007 15:28:45 GMT
Spot on Alex!! theres the valve lovers on here but I doubt any could disagree with that post
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Post by Deleted on Dec 18, 2007 5:25:14 GMT
For anybody interested in learning more about how valves work. I have a copy of a .pdf entitled "Inside the Vacuum Tube" It is a rather old book, but quite informative. It can be sent as 2 emails and recombined using a program like the freeware "HJ Split" if anybody is interested.
SandyK
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Post by FritzS on Dec 18, 2007 10:55:52 GMT
Sandy - thank you Did you know producer's of power JFET's? I know only one producer.
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Post by Deleted on Dec 18, 2007 11:20:08 GMT
Friedrich Hitachi, Vishay, I.R. , Exicon Exicon may be still making suitable replacements for Hitachi , who I believe no longer make them ? Alex
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Post by FritzS on Dec 18, 2007 11:43:49 GMT
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Post by Deleted on Dec 18, 2007 11:58:19 GMT
Friedrich Jaycar was selling those Exicon devices as replacements for the obsolete Hitachi types.
SandyK
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Post by FritzS on Dec 18, 2007 13:45:56 GMT
For mid-power 500-650 mW I found some at Farnell Today at 2:10pm, leo wrote: IRF610 etc? IRFZ24N etc? IRF610, IRFZ24N are MOSFET's and not JFET's I search JFET's with Power Dissipation between 650mW .... 10W Fairchild have some (please copy the complete link in a new browser window) www.fairchildsemi.com/sitesearch/fsc.jsp?command=toggleSort&attr1=Junction+FET+%28JFET%29%2F%2FPd+Power+Dissi pation&attr2=0&q=50&qt=1197986310&vid=%24__visitId__%24&i=part_number&qid=%24__queryId__%24&s1=Product+Volume%2F%2F0&s0=P roduct+New%2F%2F0&g=Family&a1=Family%2F%2Fv%3A0&a0=AAAFamily%2F%2Fv%3A0&as=1&qtid=%24__queryId__%24&t=0&ia=1&c2=e%3A0%2F% 2FFamily%2F%2F%3Aeq%2F%2FJunction+FET+%28JFET%29&c1=e%3A12%2F%2Fpart_type%2F%2F%3Aeq%2F%2Fg&c0=e%3A0%2F%2FAAAFamily%2F%2F %3Aeq%2F%2FJunction+FET+%28JFET%29&datags=Junction+FET+%28JFET%29%2F%2FPd+Power+Dissipation%2F%2Fasc&domains=fairchild_db %3Apart_number&text=
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Post by leo on Dec 18, 2007 14:10:07 GMT
IRF610 etc? IRFZ24N etc?
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Post by leo on Dec 18, 2007 15:47:22 GMT
Shit, I hit modify instead of quote, sorry Fritz What about mailing Fairchild and asking for a few free samples ? do you need a lot Fritz? I thought 2sk176/2SJ56 was Mosfets?
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