| tried the 6688 [message #31901] |
Sun, 18 June 2006 11:49  |
Forty2wo
Messages: 163
Registered: May 2009
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Master |
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I received a pair of Amperex 6688A. These are supposed to be equivalent to the E180F.
I put them in place of the Siemens D3a.
And in my circuit they are absolutely lifeless. So are they bad tubes? I don’t think so. Are they not really equivalent to the E180f. Maybe, maybe not.
What I think is we should be reminded that how a tube sounds must taken in the context of the circuit in which it is used.I think this is something we forget. It is easy to read that this ‘tube’ sounds great and all the others are shit. But if change the circuit, a tube type that you may have previously written off, might be just the ticket…John
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| Re: tried the 6688 [message #31905 is a reply to message #31904] |
Tue, 20 June 2006 22:28  |
Forty2wo
Messages: 163
Registered: May 2009
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Master |
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Yea, I was expecting a subtle difference between the two types. But no, it sounds like someone put a wet blanket over the speakers, only with less bass. The best way to describe it is it sounds like the tubes were thoroughly worn out and then some. I am sure that they are new, they test fine and each on there own sound the same. I tried them at the same OP as the D3a, Ia 9.5ma, Va 192, Vgk of 2.2V. these Measured with the D3a. the cathode is still not bypassed. will try that down the line. I have a 1k cc, g1 stopper, and a pair of 460 cf for the cathode. I did not detect any oscillations with the D3a. I did not check but would expect less trouble with the lower mu tube. The D3a setup, as it breaks in is sounding very nice. I will at some point try a different cathode scheme and will keep my eye out for another set of 180’s . I will continue to try them as I make changes…John
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| Re: tried the 6688 [message #31906 is a reply to message #31905] |
Wed, 21 June 2006 00:17 |
Damir
Messages: 1005
Registered: May 2009
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Illuminati (2nd Degree) |
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Strange - as I described it, my D3a and E180F tubes sound very similar, D3a a bit more "rough", and E180F little more "smooth". But both have a dynamic, open and direct, powerfull sound.
I think that with choke load you should use bypassed cathode, if not - rp of the triode goes up, not a good thing in combination with L and Cw of the choke (both frequency extremes). Maybe try the bypass first, say 100µF-220µF.
But, I noticed in 6SN7 test that, although similar, there`re differences between the tubes of the same type. Some sound "big, open, clean", and other more in "blanket, compressed, warm, unfocussed" way.
As I said, my pair of E180F is NOS Philips, unfortunately didn`t try other types.
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| Re: Amperex and Phillips E180F [message #31908 is a reply to message #31907] |
Sat, 24 June 2006 09:14 |
Damir
Messages: 1005
Registered: May 2009
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Illuminati (2nd Degree) |
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Hej, dobro dosao na forum! Pretpostavljam da si iz Hrvatske ili iz neke druge ex-YU republike (Bosna?), drago mi je da ima jos lampaskih samograditelja. Ako nisi bas vjest sa engleskim, ja cu prevoditi tvoje poruke, zbog drugih - ipak je ovo USA / internacionalni forum... 
Hvala na informaciji, kako rekoh - imam samo jedan par Philips-ovih E180F, ta lampa je visoka skupa sa pinovima samo oko 43 mm...The English translation of Rajko`s message: "Damir, Amperex E180F is a different than Philips or Siemens. It has completely different internal structure, the reason for about 1 cm taller glass envelope, no gold pins.
I didn`t try them yet, but I have no much confidence in Amperex.
I just prepare myself to build SE 300B, I have 300B`s from ex 300B-PP.
Greetings."
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| Re: Amperex and Phillips E180F [message #31909 is a reply to message #31908] |
Sun, 25 June 2006 02:16 |
Rajko
Messages: 3
Registered: May 2009
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Esquire |
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Hvala Damire.
Pa razumijem engleski kad procitam tekst, ali dosta lose govorim/pisem.Ja sam ti iz zemlje "Nedodjije" :-))). Vidim da si dobio lampe iz Njemacke. Jos ako su ti stigli potenciometri iz Amerike, onda je odlicno Ako hoces, javi se na: macakiljilja@blic.net
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