Tube rolling with the Quickie - observations...

[earwaxxer]

After reading much of the 'Crack' posts on tube rolling I feel a bit sheepish in bringing the topic up on the 'lowly' Quickie forum! But hey, I am going to keep on cheering for the Quickie! I love it, and it has transformed my listening enjoyment. Sure, I have 500wpc SS power amplification. Not ashamed of that! Not as sexy as tubes all the way through, grant you. I can also say that the speakers I'm driving to very satisfying levels cannot be done with your lowly tube amps! - There - got that rant out of the way...

Now, tube experiences with the Quickie. What is interesting is that I went from a fairly top frequency heavy modded high power t-amp, to a 'neutral' and smooth high power class A/B in the likes of the Emotiva. The change to Emotiva was spearheaded after the addition of the Quickie. The Quickie added such beautiful drive and 'staging', that the limits of the 50wpc t-amp were revealed. My maggies were begging for more. What I had become accustomed to in the t-amp sound was now a bit lacking in the Emotive. The t-amp has a certain beauty in mids and highs that were very good and satisfying. Of course the Emotiva was new and needed burning in. To make a long story short, I had the GE tubes in with the t-amp. They sounded fantastic. The Aladdin's were not nearly as smooth and sexy. A bit harsh if you will. After some listening with the Emotiva I subbed the Aladdins back in. It seemed like I was getting the best of both worlds. They stayed in for some weeks. The Aladdins also had no ring whatsoever (I would get some ring from the GE's - not bad but usually only noticeable when the music stopped abruptly or there was a quick loud noise in the room with the music off).

Anyway..I was noticing a bit more fatigue than I thought was necessary, although I was listening at higher volumes, so I switched the GE's back in. Wow. Talk about a very cool tone control effect. The bass improved significantly (my sub was blending now much more coherently). The highs had a very nice sparkle (almost like the old days of 'loudness' control). The mids were somewhat less intense but very smooth and agreeable. Very good rock and roll tube with my setup. How cool is that! 

So there you have it. Other experiences welcome. I also have the RCA's. I have not experimented with them with the new amp. Not sure what I would want in a tube roll at this point, but hey, we're never happy for long! Thats what makes us 'audiophiles'.

[Noskipallwd]

Hey Eric, I thought maybe I would resurrect this thread, I have found tube rolling with the Quickster very interesting. What amazes me is the different results that Quickie builders have reported for the same make valves, with respect to microphonics and SQ. I guess I'll list the tubes I rolled and my impressions.
Georges(stock tubes)- Sound is pretty good but microphonics from hell! Actually the ring it makes is quite beautiful, I was thinking if I could get a few tubes of the same construction with slightly different envelope size, I could make an interesting musical instrument out of them. I could call it Tubular Bells, (Pun was intended).
RCA - got these on ebay and they are great sounding tubes, with little microphonics. (like I said, same tubes different results) These have clearer highs and tighter bass than any others I have tried.
Tung-Sol -close second to the RCAs, low microphonics but less accuracy in the low-end.
Mullard DL92 - Very low microphonics, seems to lack clarity in the upper frequencies and sounds a little dark for my tastes.
Sylvanias - Very microphonic, an overall muddy sound, maybe I got a bad pair, but worst of the bunch.
I share your enthusiasm for the Quickie, it never ceases to amaze, how good this little pre-amp sounds.

Cheers,
Shawn

[earwaxxer]

Hey Shawn! - thanks for the input. Interesting run down on the commonly available 3s4 tubes. I agree with your take on the RCA's. I am listening to them for some time now, and I think they will stay. I did manage to order some Mullards from England a little while ago. I think they were used (like very used). Strange ponging noises and some occasional static from one of them. I think I have the Microphonics tamed for the most part. Pic shows my home made tube dampers. I used 3/4 inch copper tube. lined it with velcro so that the tube fit snug. I coated the outside with 5-6 layers of tinfoil bonded with epoxy, then painted it black. Lastly I stuffed the pipe with several earplugs each, and wrapped with rubber bands. I might add even more rubber bands. It seems the more the better. I agree with that perfect ring note! Very sweet. I havent had it with the current dampers I'm using.

Cheers - Eric

[Noskipallwd]

Ha, those are great, I think they should be called tube cocoons. I am using dampers from Herbies audio lab, I have always had good luck With them. I painted my top plate, (Batteries are mounted on the underside), using shellac based primer and Hammerite paint. Surprisingly this reduced microphonics, must have changed the resonance of the plate. I think the single best mod I have made so far was putting the Khozmo 48 step attenuator in, cost more than the kit though. Right now I am running my TT to the Eros, to the Quickie, and then to my Crack. I set the Cracks stepper to a decent level and use the Quickie for volume control. By the way, I read where you replaced the cathode bypass caps with films. I have a couple of Obliggato 49uf PS caps sitting around, I wonder if 49uf would be enough to keep from rolling off too much bass. Maybe I will clip them in and give it a try. Take care.

Cheers,
Shawn

[earwaxxer]

I have a couple of Obliggato 49uf PS caps sitting around, I wonder if 49uf would be enough to keep from rolling off too much bass. Maybe I will clip them in and give it a try. Take care.

Cheers,
Shawn

The 49uF would be adequate. I think Paul said the math comes out to 43uF or above. The Obliggato's would be a good pick. Not a huge difference IMO, but a no brainer. I'm sure the stepped attenuator would be a good upgrade. I like the log taper. Kind of picky about getting the exact volume I want at the time.

Cheers - Eric

[coca]

Shawn, which herbie's halo dampers are you using for the quickie preamp?
I use the halos a lot, but always depending on the situation.

Bernie.

[Noskipallwd]

Bernie, on the quickie I am using the ultrasonic ss dampers, the 3S4s don't get hot so I thought Halos would be overkill. I do have some Halo IIIs on another amp.

I'm sure the stepped attenuator would be a good upgrade. I like the log taper. Kind of picky about getting the exact volume I want at the time.

Cheers - Eric

Yep, that is a problem with steppers. I have a 24 step Goldpoint in the Crack, and I do wish for more fine control. The Khozmo is 48 steps which is much nicer, unfortunately I have the discrete resistor version so it would not fit in the Crack.

Cheers,
Shawn

[Doc B.]

I find the notion of the criticality (sp?) of the resolution of the steps of a stepped attenuator interesting. IME some systems need to have the level at a certain point to "bloom", for lack of a better term. My hunch is that this is due to room modes primarily, and to a somewhat lesser extent the frequency response of the speakers themselves. Note here that I am not casting any aspersions or dictating any rules. Just making an observation.

[Noskipallwd]

I find the notion of the criticality (sp?) of the resolution of the steps of a stepped attenuator interesting. IME some systems need to have the level at a certain point to "bloom", for lack of a better term. My hunch is that this is due to room modes primarily, and to a somewhat lesser extent the frequency response of the speakers themselves. Note here that I am not casting any aspersions or dictating any rules. Just making an observation.

Doc, I have been thinking about what you said, I confused myself at first(something I excel at). I think I understand now, lets see. So you are saying that systems can have a 'sweet spot' or maybe 'sweet band' would be more accurate. A small range of volume levels where the room, speakers, and to a lesser extent the other components in the chain have a sonic synergy. Which can produce optimal sound for said system. Which makes the number of steps on an attenuator of little importance. So is that close, or am I completely of base?

Cheers,
Shawn

[Doc B.]

Yeah, if the speakers are down low they may not sound as full bodied. As you turn up the level you often find a place where the music sort of reaches lower midrange balance, which is what I think of when someone says "bloom". If the steps are far apart the sweet spot where the effect just starts without the music getting a little too loud might be between steps. Or it might not. It would depend upon the speakers and the room.

There's a lot of theories about it, including the notion of the Fletcher-Munson curve. I just took a look at the curves and it is interesting to note that the bottom end seems to be getting pretty flat right at the average listening level in a mastering room of around 82dB. Levels below that is where the F-M curve indicates you need some bass compensation. This assumes your speaker's response is flat and your room does not influence the response, which it of course does. The current standard for equal loudness contours does not agree with F-M down there and basically says you always need bass boost below 100hz, anywhere from 30 to 70dB at 20Hz. Sure seems like some audiophiles I know take that to heart...

[John Roman]

Hey Shawn,
Those are the first affordable solution I've seen for tube dampers. I just checked that site out and I may give those a try. I appreciate the tip.
John

[Paul Joppa]

Many decades ago, SpeakerLab did some experiments with loudness, using a musician (acoustic guitar IIRC, possibly a small combo too?) with microphone in one room, reproduced in another room. They found that the sound was clearly most believable when the loudness was within a couple dB of what was measured in the source room.

Unfortunately they didn't have a symphony orchestra at hand to see if it depended on the size and scale of the source (!) but an informative experiment nevertheless.

[Noskipallwd]

Gone tad off topic but this is interesting so who cares. Okay it is making more sense to me now, Doc. If the study Paul posted about is any indication, a couple of Db is pretty tight. That could fall between steps easily. I have heard the same 'bloom' in headphone systems as well, switching cans I always have to adjust the volume to sound right. Would the causes be the same? Frequency response of the drivers, and the morphology of the headphones, Ie. size and shape of the cups, open or closed back, and the material they are made of, and so on...
You are welcome John, they work better than anything else I have found, not sure why. If you are using them on tubes that get hot you want the Halo models. I bought a  Project RM-3 TT from a neighbor just to see what I could do with it, sounds pretty good for a 500 Tt. It had  a S shaped arm that picked up motor hum from the plinth, I put one of Herbies dampers on the arm and it killed the hum.

Cheers,
Shawn

[earwaxxer]

Many decades ago, SpeakerLab did some experiments with loudness, using a musician (acoustic guitar IIRC, possibly a small combo too?) with microphone in one room, reproduced in another room. They found that the sound was clearly most believable when the loudness was within a couple dB of what was measured in the source room.

Unfortunately they didn't have a symphony orchestra at hand to see if it depended on the size and scale of the source (!) but an informative experiment nevertheless.

Hey Paul - Quick off topic comment about the SpeakerLabs. In the mid 70's I built their large double walled cabnet with the 12" and 10" woofer, with the large midrange horn, and tweeter horn. Those baby's could do some db's. Had an SAE 200wpc. and preamp feeding um, with a Thorens tangential tracker. Wish I still had them. The good old days!

[Noskipallwd]

Hey folks, I picked up 4 Telefunken DL92s for the Quickie, so far they might supplant the RCAs as my favorite. Low microphonics, really tight Bass, bright but not too much, overall less fatigue and a pleasing tube sound. I also replaced the cathode bypass caps with some 47uF Obbligato film caps, really happy with this change. No percievable change in low frequency roll-off. Definitely worth the effort.

Cheers,
Shawn