Spørsmålet er vel ikke så relevant, da du ikke kan velge AC eller DC, du må ta det som følger med den modellen du kjøper. Og det er jo hele konseptet som teller, ikke bare strømforsyningen. Men tilfeldigvis designet man den første med en AC-adapter, den neste modellen ombestemte man seg og valgte en DC-adapter.
Skal jeg forklare hva AC og DC er ? Altså vekselstrøm og likestrøm.
Alle strømforsyninger er AC-forsyninger (fra lysnettet/stikk-kontakten), men et eller annet sted befinner det seg en likeretter som lager DC, som er den kjørestrømmen enhver forsterker må ha. I den første modellen sitter likeretteren inni hoved-apparatet, i den andre har man valgt å plassere den i adapteren man plugger i veggen.
Ble det klarere nå ?
Viser resultater 41 til 51 av 51
02-28-2009, 23:35 #41
03-01-2009, 03:20 #42
Jeg holdt på å kjøpe VP130 fra USA, men det hele strandet da jeg spurte om 220V strømforsyning. Da fikk jeg som svar at jeg nok burde få tak i den europeiske versjonen. Ikke vet jeg om dette egentlig er noe stort problem, men selgeren hadde tydeligvis ikke mange forslag å komme med, eventuelt så var han ærlig og ga meg bare en anbefaling.
03-01-2009, 15:33 #43
Jeg vet forskjell på ac og dc. Jeg uttrykte meg kanskje ikke helt klart. Det jeg lurte på var om det hadde noen speifike fordeler mht lyd eller støy å ha likerettingen eksternt kontra internt ?
03-01-2009, 15:45 #44
Ja det er en fordel å ha likeretteren i hoved-apparatet. Det gjør elektronikken mindre sensitiv for forstyrrelser/dårlig kontakt, kabel-effekter, etc.
Så jeg syntes den opprinnelige løsningen var gjennomtenkt.
03-02-2009, 22:34 #45
stapedius: Flott om du kan høyra med han karen du kjøpte Bellarien av, om det er mogleg å få ein pris rundt 2500 svenske kroner. Dette er litt meir enn du gav, men mykje mindre enn det som står på heimesida, så det er vel tvilsamt om dette går. Men som sagt, kjekt om du vil prøva.
03-03-2009, 01:45 #46Opprinnelig postet av 2rr
03-15-2009, 18:47 #47
Sidan svar lar venta på seg, og eg byrjar å bli litt utolmodig etter å få lagt inn ein bestilling, trur eg at eg satsar på Needle doctor. Så får eg heller leita fram ein strømforsyning her i landet...
03-16-2009, 04:12 #48Opprinnelig postet av 2rr
03-24-2009, 06:57 #49
3.700,- (SEK) minus moms (25%) er det beste de kan tilby..
03-26-2009, 20:33 #50
OK, ja det var vel det eg frykta. Men takk for hjelpa uansett. Trur eg legg inn ein bestilling her LP Tunes - Feast your ears.. Får da med 230 VAC power supply.
Fekk du forresten med alt du trengte til platespelaren din Stapedius? (ref. handlelista i ein annan tråd)
04-11-2009, 18:08 #51
NEI NEI NEI og Atter NEIOpprinnelig postet av Legatia
JJ ER JJ og Tesla er TESLA
Se ★ J A C - M U S I C ★ EMISSION LABS TUBES ★ YAMAMOTO SOUNDCRAFT ★ NOS TUBES ★ You must like: for en lengre utredningHer er artikkelen :
Why JJ tubes are not Tesla tubes
There is a common misunderstanding in the internet called TESLA-JJ tubes. I don't know which duck invented this word, but such tubes don't exist. There are TESLA tubes, and there are JJ tubes, both made in different factories, by different people, with different technologies. Only the machines are the same, and in the Tesla days they were new, and now they are old. The used materials definitely are not the same. TESLA has used the cathodes from the former TESLA Rosnov factory, but this factory is closed now. Also wires, and nickel technology came from Tesla plants that are all closed now. Cathodes are elementary for tube performance.
May be you know that Yugoslavian "EI" ECC-series tubes are made on old Philips machines. This is EXACTLY the same situation, but I hear nobody talk about EI-Philips tubes. They are regarded something different, which is correct.
Until 1997, the world market prices of tubes like ECC83 were relatively low. There was enough NOS around. Many people thought this situation would always stay that way, and the TESLA management thought so too. (Later they understood the mistake, but were not successful with re-constructing the KT88 tools)
The Russians sold NOS EL84 for 200$ per 1000, and from China you could buy good EL34 and ECC83 for incredible low prices, if you knew the way. It was by that time that TESLA decided to sell off their line of Audio tubes to JJ. In the last years, the TESLA ECC83 was sold for only 2 € in OEM quantities, by company in Austria, who claimed to be their exclusive distributor. From this you can see that the factory price must have been very low. After selling off the audio line, TESLA went on making transmitter tubes, and other devices like vacuum capacitors, and military devices, which they considered more profitable.
So the TESLA tubes like ECC83, EL34, and KT88 were out of production now. The machines were moved out of the building and reinstalled at a factory of a man called Jan Jorgo, better known as JJ.
Unfortunately for TESLA, this was a big mistake. In the years after that, Ebay made the NOS prices soar, and as we write the year 2004 now, NOS prices they still rise 20..30% per year. NOS KT88, or ECC83 is practically unavailable in quantities. Russians and Chinese tube factories raise their prices twice a year due to higher energy costs and higher cost of all kinds. It appears that JJ made a perfect buy!
Since most JJ tubes are made with old TESLA tools, differences are small. They do use a different cathode, because the TESLA cathode factory in Rosnov is closed now. Both TESLA and JJ used to get their cathodes there. So NOS TESLA tubes have cathodes from Rosnov, and where JJ has their cathodes from today, I don't know. This is one difference.
Identical tools are used
Another difference is in the part numbering. E88CC originally is a long life version with gold plated leads, but the TESLA version has only normal leads. In the below picture you can see this difference clearly.
Gold pin TESLA tubes vs. JJ .
The next difference I noted, are some costs savings on the shielding. With this tube there is a shielding plate between the two triodes. With the TESLA tube, they did something nice. The shielding plate was coated black, and is used to transport the heat out of the tube center. So is is used a cooling fin. This is great, because the center anode plate is already hotter than the outside anode plate.
Gray coated shield by TESLA
With the JJ tubes, exactly the same shielding plate is used as with the TESLA tube. Only JJ uses lower cost, untreated white nickel, so the cooling fin function is not present any more. This will give the old TESLA tubes a better lifetime expectation. In vacuum, only black material will radiate heat very good.
For the Czech Post, a GOLD GRID version was made. These are little jewels. Highly underestimated. Most of them have yellow printing. These are from the 1960's.
Here you see a close up of the gold plated grid bars coming out of the mica. So obviously they did not use just gold plated grid wire, they gold plated the complete grid after it was made. What a quality this is!
TEST RESULTS JJ vs. TESLA NOS
I bought a lot of 20 pcs new JJ E88CC (one of those I have pictured above). On my tube tester (Metrix U61B) initially they tested very nice. Then I let one tube warm up, and apparently it started to reduce plate current slowly. This was curious, because with NOS, I never had this. Well ok, JJ is new production, so I thought this was the explanation. I though they need some more burn-in perhaps. So I let the tube run on the tester, and the next day it was testing weak. Oh well, I thought one bad tube out of 20 can happen. Then I tested another, and another and they all went down 5% per hour. I sold this lot where it belongs: on Ebay. I wrote in the Auction why I sold them, and they were with the option to return if not satisfied. Bidders were fighting for them. How typical for Ebay. I got a higher price than expected, and the buyer was satisfied he wrote me. Well, then everybody is happy.
When testing TESLA gold pin E88CC, the experience was so much better. First of all, the needle of the tube tester goes up faster as with the JJ's, and that gave me a good feeling. Same as with all NOS when I see that. Then after the initial heat-up, the Tesla's change their readings only very little, and give a totally stabile reading after just minutes. Wow! Then they keep just this value no matter how long (hours or days) I let the tester run.