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Tube rolling the Quicksilver Audio Horn Monos


Tarheel

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With 25 watts I don't see a high plate voltage and after looking at the owners manual I see the amp was intended for this entire family of tubes.

I do agree with Duke here one does have to pay attention to high plate voltages especially with the EL34's and when its high one might use the Industrial EL34 "6CA7" which can handel high plate voltages.

As for the 88's I've always enjoyed these tubes. The sound you should find warmer with more dynamic impact the KT90's are another favorite with the same characteristics with a 50watt plate dissipation v.s. the 88's 42watts. EL34's are 25 watts and 6550's are my least favorite and some of my friends won't even touch them.

New Sensor does 24hr burn in before matching BTW where as Mike does 10hrs

Enjoy!

SET

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Please excuse my ignorance here, but is it wise to put in a tube that has more power dissipation capability in a unit that say was designed for less output power ie, current draw, output transformer, like in the above example, replacing an el34 with a kt88?

Just asking because I am curious

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Please excuse my ignorance here, but is it wise to put in a tube that has more power dissipation capability in a unit that say was designed for less output power ie, current draw, output transformer, like in the above example, replacing an el34 with a kt88?

Just asking because I am curious

No Problem Jack,

Many of these tubes belong to the same family meaning they have the same pin out or with pin 1 tied to pin 8 for the EL34 it allows you to run 6550's 6L6's KT66's KT88's KT 77's KT90's this entire family of tubes providing that the amps biasing and plate voltages are within range meaning you don't exceed the tubes specifacations like its plate dissipation which is a product of plate voltage and plate current. You can run a KT90 with a plate dissipation of 50 watts at 25 watts but you can't run a EL34 with a plate dissipation of 25 watts at the KT90's 50 watt dissipation and so on! One friend of mine has a Jollita 6550 amp that he runs KT90's in it! not that I care for the Jollita but it sounds considerably better with the KT90's in it!

The Horn Mono is such a design! NOS Valve amps are another that allows this!

Sounds like fun huh!

The Horn Mono's are self biasing which makes things easy just plug n' play! A fixed adjustable bias is another story! One just dial's the correct bias current sometimes thats just a voltage drop across a small value resistor this sets the bias current or think of it as a fixed idle power setting that all the tubes will operate at.

If the design allows for a range of bias current then it is that much more versitle.

SET12

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Set12,

Thanks for the education. Years ago I did some electronics, but you know the old saying if you don't use it you lose it. I still do a little now and then on my Ionovacs. I'll have to check out my Dynaco ST70 I recently picked up (uses EL34's) Actually I am thinking about sending it to Craig at NOS Valves for a complete rebuild. I also have a Mac 240 that uses 6L6's humm.....

Jack

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Hi Chuck,

I figured I'd chime in here because I own a pair of the Quickie Horn Monos, as well. My main tubes are the Valve Art EL-34s (wonderful tubes, by the way), but I have experienced equally, if slightly different, results with the re-issue Tung-Sol 6550s.

Where the Valve Arts are smooth and liquid (I use them primarily for jazz, instrumentals, and vocals), the Tung-Sols are detailed and dynamic (I use them with rock, pop, etc.). If you think your HMs need a little more low end grunt and dynamics, I recommend the Tung-Sol's. Or, if you have never tried the Valve Art EL-34s, I highly recommend them.

William

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I have heard original Tung-Sol's and I recall them as some of the nicest sounding of the 6550's indeed, Some of my friends have had the most damage done to their amps by 6550's which is why they like to stay clear of them.

My self I have only ever heard one 6550 amp that I really took a likeing to. A Russian designer with a name that began with an A. I can't remember the name they were 100 watt PPP monoblocks just beautiful sounding and at 5000$ a pair they should be.

EL34's are nice but for the most part the 88's and the 90's are where its at IMO. And I'm sure NOS Valve is under the same assumption for sheer dynamics these tubes rock!

SET12

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Just to clear something up to the novice that may not understand what plate dissipation means. When someone say's a KT90 has 50 watt plate dissipation rating this has nothing to do with the actual watts the amplifier the tubes are installed in produces. The dissipation is the heat that the plate is transferring measured in watts. If you exceed this plate dissipation by much the life of the tube will be shortened and you may have glowing red plates.

500 plate voltage X 100mA current = 50 watts of plate dissipation. A pair of KT90's could be making over 80 or so watts of output power in this operating environment (loosely figured many other variables come into play)

Craig

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Thanks for the help guys. I posed the question and then went out of town before I got your answers. I would really like to try the 88s but I don't here anyone saying to do it.

WPM, Since you have the horn monos have you tried the 88s or 90s? I certainly don't want to damage the equipment but the self biasing feature was a selling point to me when I bought the amps.

I will email Mike at Quicksilver before I make a move.

Craig on another subject..... you suggested I move my cabinets out from the wall 8'' to increase the bass for my LaScalas. How does that work since the woofers fire to the front?

Chuck

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Talked with Quicksilver Audio....Suggested that I ask for low bias voltage if I go to KT-88s. Said that the Tesla KT-88s sound particularly good but again I should order the low bias matched pairs. $120 a matched pair....ouch!

Thank you to all responded as I am indeed a novice.

Chuck

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Hey Chuck,

I never tried 88s (with the Horn Monos) but tried a quad of Tesla 88s in a Jolida 502A I had some years ago. I found them to be a bit too robust for my liking. Great tube if you need power, but I tend to favor tubes that deliver a more euphonic, lush sound. As for the 90s, I have never tried them.

If you go the 88 route, post your findings. I'd be interested to know what you think.

William

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Thanks for the reply William. I still have not decided on tubes for the monos. Its not like you can go listen to them side by side in your amps. I think I will retube the Quicksilver Audio Full Fuction Preamp first and go with the original tubes from Quicksilver for $109/set.

I see you have some Cornwall IIIs coming or have they arrived? Let us know how they sound with the horn monos.

Chuck

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Chuck,

The Cornwall IIIs are still being built. They have about 4-weeks to go [:(] (it seems like an eternity). Luckily, I've been able to borrow a pair of Reference 3A De Capo speakers to hold me over. I must say, the De Capo/Quicksilver marriage is quite a surprising combination, though I am longing for the Cornwall's dynamic range and bass.

I will post a full report with pics when the Cornwall's arrive.

William

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20-25mA in what tester? A maxi matcher? If so at what settings on the tester? I know someone that may be able to hook you up but need more info on this 20 - 25mA rating.

Craig

Craig.....I have no idea but I will forward the email I got from Tube Depot if you don't mind. I am using Tesla 34Ls but would like to try other tubes if I can do it safely. I am a novice in way over my head so any reccommendation will be appreciated. This is my first tube gear. If I stay with the 34L do you have a brand preference? I will be leaving my pc in about an hour so I may not get your reply til monday. Thanks much.

Chuck

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Chuck,

Got your emails.

Without knowing the electrical envoirment that this 20mA to 25mA is measured in it's pretty hard to advise you. You need the plate, screen and grid voltages that produce the 20mA to 25mA that QS recommends. I bet these are Maxi Matcher test results at 450V plate and -48V grid but I'd rather be sure about it. If you can find this out I suggest you give Doug at www.dougstubes.com a call he uses a maxi matcher and may have a few different quads he could supply you.

Craig

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