edwardre

Q - Too late!!!! My set is in the mail!! But not to worry, I am nothing but pleased to be able to check it out for myself. FWIW, the 'ear' test is truly the only test I value (except for gross non-conformities). It's one of the reasons I purchased the CobrEflEx's.....based upon several 'unscientific testimonials' which, BTW, are the only type of endorsement anyone ever gets from me!

Ed, I too will be interested in your opinion of the Cobraflex horns. As for the SAHF driver, is it a direct bolt-on to the 511B or does it need the adaptor just like the K55? Have you tried the Altec 902-8A with the 511B's? Tom Brennan seems to prefer that driver with these horns. ---------------- Mike, the SAHF has the same thread size and pattern as the K55, so an adapter is required. This is another reason that the Cobra is intriguing to me as I've always wondered about adapters and the effect thereof. Some are longer, some have smaller or larger inner diameters, burrs, etc. Just a host of inconsistencies that provide that ongoing slight doubt.....I have not tried the 902-8A with the 511B's. This (correct me if I'm wrong) had appeared to be a 'higher-end' driver costing considerably more than the SAHF or K55s, and thus I would expect it to perform accordingly. Would be interesting to see if others who have made the comparison feel like the improvement is as exponentially positive as the exponential price of the driver. Also very interesting to me were Q's comments about the SVS. I believe that this is the first mention by anyone that I have read that portrayed a SVS in anything but stellar light. Mike, I'd be interested in your opinion of your SVS, and whether it fills your HT needs? I was first 'tipped off' to the Cobraflex by Chris (Mungkiman) who was on the side of 'sounds terrific'. Add to that both Mike and Q's very positive review and now I can't wait to preview it myself. John W has mentioned that there are differences between the original Cobraflex and the II's, III's. The ones I bought are the originals. John....are the originals 'reflex expansion' types too and exactly what does that mean? Mike/Q.....was the Cobraflex you all previewed an 'original', II, IIB, or III? Visually, they all look the same to me. Finally, WRT the 'folded horn' comments/concerns, I too feel that the folded horn looks exceptionally 'utilitarian'. For use as an air-raid siren and other loud, brash, PA type applications. Just the general 'looks' lends itself to non-musicality. Although I still feel that the folded horn style is visually unappealing, the audio perception has been shattered to oblivion. About 9 months ago I received a Cobra 12 horn. This guy looks very similar to the 511B. "Sectoral-type" horn with the folded horn throat (?) visually protruding from within the center almost to the outer edge. It is also of thin, tinney construction and has a built in driver that is non-replaceable with any sort of 'upgrade'. How could this 'thing' have any musical qualities at all? After discovering that the driver could not be replaced, and the 'folded protrusion' unremoveable, it sat in the garage for 6 months unattended. One day on a whim I hooked up this thing, a 4401 tweeter and a 12" University woofer through a Klipsch AA network. I have to state in all honesty that this mid-horn, in all it's unconventional look and construction, was one of the smoothest, most revealing horns I have ever heard. It's currently hooked up to my tube amp in the garage, with the other channel hooked up to a 12" JBL woofer/K400-K55V/K77 combo. The all University package (except for net) BLOWS AWAY the other package in every single catagory. I have never seen another Cobra 12 anywhere, but would ****** one up immediately to make a pair.

OK....based upon your 'glowing reports'....511B vs Cobraflex.....I immediately went out and scored a pair of these from 'the bay' (before the rest of you drive the price up out of my range!!!). $52 for the pair. As most of you know, I've been a '511B-man' for over 15 years now and absolutely love them. Been praising the wider dispersion for a long time. However, they are not without drawbacks. It's a very 'deep' horn (front to back) and as such, sticks out the back of the Belle considerably. The University piques my interest in this arena. Upon receipt, I'll be looking (or listening) to how the Cobra integrates with the 511B's in my Khorns, if the 'blend' is an additive of the positives or not. Especially where DVD-A is concerned. Hope to have a report soon, they have been enroute since yesterday. Mike - If you like the 511B/K55 combo, you owe it to yourself to give the 511B/SAHF combo an audition. It is (IMHO) even more clear and articulate than the 511b/K55.

Did you try looking it up at www.hifilit.com?

Hey Craig, does the 5ar4 affect the sound much if at all? Is the only benefit of a Mullard in this role the longevity? Finally, I purchased a JJ/Tesla 5ar4 from Ned awhile back. How is the Sovtek better? Should I replace the Tesla? Thanks!

What does it mean when the metallic silverish 'cap' part of the tube is virtually gone? Or, more to the point, what is it and why do tubes have this 'inner glass coloration'? One of the tubes in my preamp has just a few specs of this left....it's virtually clear up there. Bald looking. Seems to work fine. Swapping it with the other channel's tube has no effect (that I can tell) on the sound. Should I start looking for a replacement? Is this tube starting to die?

Yeah, yeah.....Mike, where's that 511b review???

Yeah, it certainly appears that this topic has been beat to death in about every audio forum known to man with the bottom line being the bottom line with just about everything audio.....personal preference. I thank you all for the input and for your patience in 're-hashing' for this tube-newbie. I have to say, I really enjoy this whole tube thing. This is turning out to be one of the most enjoyable passages of time I've had in a while as it pertains to the joys of audio. Everything being discreet (component wise) makes for practically unlimited 'fiddling'. You could never ever in a million years tinker with SS to this degree. It seems like every single thing I do to it makes some sort of audible difference. I doubt I will ever be truly 'done'. Pheasant season is looming for us Californians. Early this summer, I purchased a 'project' travel trailer for bird hunting season. It's a real piece of work. Dry rot everywhere. As a result, I've spent endless hours in the garage restoring it. This affords me endless hours of music listening, as the tube test bench shares the garage. My MO of late has been to come home from work, swap a few caps, resistors, etc on one or the other (Preamp or amp) then spend several hours listening. In fact, I've just come in (it's 12:30AM-ish). Today's 'swap' was to replace two of the last 4 remaining caps that were stock. The 82pF's in the general reigon of the main output coupling caps. I have a bunch of Mallory SX series polystyrene caps that I got en masse with the orange drops. Just so happens there were a handful of 82pF's. I matched up 2 and installed. (The old stock ones measured out to be about 65pF). These seemingly insignificant caps made a huge difference. Almost as much as the main coupling caps. The improvement was very noticeable. Rich sound with no harshness. I have noticed that I like the polystyrenes over the polyprops. They are detailed and have no harshness whatsoever. "Airy". Seem to increase imaging. MD - It is now apparent that the Jensens will have to be tried! Thinking of ordering up 4 this coming week. For now, those Solens are out. I also cut way back on the size, from the 1uf Solens back to the .1uf Black Cats that were originally there, in parallel with 2 .25 Orange Drops for a combined total of .6uf. They are likewise matched within 1%. This is a fairly good sounding combo that seems to bring out the best of both types. Most of the rest of the Orange Drops are being replaced, by the pair, for the polystyrenes. But like you said, everything in the signal path impacts the sound, some subtle and some more noticeable. There are some OD to Polysty swaps that sounded worse. Anyway, onwards. Have you had any experience with the polystyrenes? They certainly have a different sound than the polypropalenes.

Hmmmm.....ok then, what the majority of you have said makes sense. While 're-capping' my tube preamp and prior to starting on the tube amp, I was testing each 'enhancement' prior to going on to the next set of caps to replace. As the tube amp was partially disassembled and inop, I ran the preamp into my ss Bryston 2B-LP 'test bed' amp to gauge the effects each set of caps changed made. Then when I finally moved over to the tube amp, I noticed that the difference between it and the ss Bryston were very subtle as compared to the difference between the ss pre and the tube pre. I just thought that the Bryston ss amp was 'warm and tubelike', or that the ST70 was a little 'raw' where tube amps are concerned. Thanks for the insight. Ed

Ooops! Above post posted to the wrong topic. A thousand pardons. Craig, thanks for the offer. I would be delighted to attempt a 2nd bias pot 'enhancement'. Yes, the ST70 supplies negative V to the output tubes. It did have the selenium rectifier but I replaced it with a diode. There is plenty of room to fit and I will send you the schematics in an e-mail. MH - I received and installed the Solen Fast-caps last evening. PU. Even after several hours of the disputed 'break-in' they were all but unlistenable. To me, the describer 'harsh' refers to an overemphasis on upper mid to high freqs that lends itself to quick fatiguing. Not only are the Solens (in this app) 'harsh', but they are likewise 'hard' across the entire range and completely de-emphasise any semblence of bass. With the bass cranked to the pin for both channels, it was/is still sadly lacking. There's $7 tossed into the toilet. With that in mind, what would be a good coupling cap? Other than $20/per Jensen oils!!! Not sure if I want to invest $80 for this enhancement quite yet..... Thank

Hmmmm.....ok then, what the majority of you have said makes sense. While 're-capping' my tube preamp and prior to starting on the tube amp, I was testing each 'enhancement' prior to going on to the next set of caps to replace. As the tube amp was partially disassembled and inop, I ran the preamp into my ss Bryston 2B-LP 'test bed' amp to gauge the effects each set of caps changed made. Then when I finally moved over to the tube amp, I noticed that the difference between it and the ss Bryston were very subtle as compared to the difference between the ss pre and the tube pre. I just thought that the Bryston ss amp was 'warm and tubelike', or that the ST70 was a little 'raw' where tube amps are concerned. Thanks for the insight.

Generally speaking, is the "tube sound" more the province of the preamp or the amp? (When they are seperate components) If I were to focus upon one or the other to upgeade/enhance in an effort to achieve 'the ultimate tube experience', which one would that be? Within a tube based unit, are the tubes themselves the item most responsible for affecting sound quality?

Yes, MH....regrettably I did get them for coupling. Didn't do enough homework, evidently. But, on the bright side, they were only $7 total and can be replaced....uh....I mean.....WILL be replaced based upon the latest I have read. Thanks for the link.

MH - Aw man.....I told you all I don't know beans from beef jerky about this tube stuff! Looking for a decent 1uf/400v cap, I read on several websites (other than Solen's!) that the 'fast cap' was ideally suited for use as either a network cap or a coupling cap. Just like I read about the orange drops. Jeepers. I guess I should 'mine' for answers more thoroughly in the future. So....guess I will try the fast caps to see what the sound is like, as they were only a buck or so apiece, I'm not out too much and I can at the same time, preview. C&S - The mod I was referring to was the Van Alstine one detailed in the 1982 Audio Basics, the one Colin provided a link to at the top of this thread. Additionally, I've replaced the other old fading caps with Sprague 'orange drops'. As several have (since) mentioned, they lend a rather 'harsh' sound, but so far not too much for my taste as I'm hoping that they will 'break-in' to a more mellower eventual sound. They do provide a lot of clarity as compared to the originals. I figure that caps are relatively inexpensive and since I like to tinker, this tube thing is right up my alley. Thanks for all your suggestions.

I have been fooled more times than I would like to admit. Primarily with a DTS flick. Naturally, the missus is duped far more often than me....I have seen her jump out of her skin at a sudden loud rear noise, get up in disgust and proclaim "I hate these damn speakers", and stomp out to watch a 'Law and Order' rerun on 'regular' TV. Go figure. The dogs are another source of entertainment with a well recorded DTS soundtrack. Usually they just lay there suffering through it, but every now and then......

Yeah, that was my thought.....let the new sound soak in for awhile then adjust my thinking accordingly. Are the leads the only thing different between the 716p's and the 715's? I don't think mine have either identifier on them. How would I know what I have? Thanks!

I have almost finished performing this 'enhancement' to my ST-70. Despite the fact that the Rat Shack no longer has the items required, I did manage to aquire the lion's share of components locally except for the 1uf 400v coupling caps. I have Solen 'fast caps' on order from Welborne, should arrive soon as the order was placed early last week. In any event, for now I've substituted with .68uf's. Larger than the original .1's, but not quite up to the minimum spec of .8. After setting the bias to 1.56V (BTW - do not replace the 10K resistor with an 18K like the missive states, you probably won't get the bias to go lower than 2v. Leave the 10K in and try it first.), I've been running in this config for about 25 hours now. My initial impression is positive. First, the tubes definately burn brighter. Like little beacons even under the bright florescent lights of my garage. Hope this doesn't accelerate the life expectancy. Soundwise, the article pretty much nails it. Whereas in stock configuration the bass was overly 'boomy' 'loose' 'undefined', especially at decent sound levels, it is now much more taut and articulate. Overall throughout the freq range, there is a healthy robustness while retaining the original musical qualities. More importantly, the response is even across the amplitute range. It 'sounds' the same at low or high volumes now. Although this is a bandwidth limiting mod, I can detect no decrease in freq. response. In fact, if anything, the highs sound more 'airy'. Finally, there is a tremendous reduction in 'hum'. Used to be that I had to try different wall socket/extension cord/2-prong to 3-prong adapter combos to reduce this (like my KSW200 subwoofer). Now, it does not matter what I plug it into, it is dead quiet. This alone would be worth the few pennies it cost to enhance. All in all, for someone just breaking into the tube scene (like me) who has one of these and is a 'tinkerer', this is a nice little project that serves to familiarize you with your equipment beyond just the on/off switch. I recommend it for those with a (very) basic level of electronics exposure as well as a fundamental knowledge of how to use a soldering iron.

Cool! I'll be busy taking fresh pics the next few days. Really appreciate it! BTW - Great job on the site itself. Neat to have member's (and other's) setup's all in one place. Keep up the good work!

Well hey Justin, that's mighty generous of you. I might just take you up on that. Should I just send you an e-mail?

Hi Fred, thanks for the input. You're the 2nd person who has said that 715/716's wouldn't be their first choice. However, I've read that they are suppose to be a good 'upgrade'. Would be interested in hearing your reasons for not using? What would be a good substitute? WRT tubes, think I'll just wait it out and try and score a Mullard from e-pay to match the 3 I have. Thanks!

So...with the advent of the 'new and improved' BB format, it would appear that the 'comments' section of the profiles were not migrated over from the old format? Where then should we list our equipment? A year or so ago there were 'discussions' as to the value of adding your equipment to your signature as when people searched for specific information, anybody with that equipment listed in their sigs would be ID'd, thus 'polluting' the search. One solution is what a lot of folks do....have a 'My System' link as a sig. However, not all have someplace to do this. Suggestions?

I heard from HornED via e-mail a week or so ago. He said he had been 'out' for the past few weeks and is leaving for another 'out of pocket assignment' at the Northern California Renaissance Pleasure Faire in Gilroy CA, working the Enchanted Garland booth.

Thanks all for the input. Dean - the JJ's have maybe 10 hours on them Purchased as a matched quad from Triode awhile back. The Mullards are at least 25 years old. When I had them tested a year or so ago, they were still good and fairly 'matched'. Mobile - I 'upgraded' to the Orange Drops only because they were readily available and I had read that they are tonally desireable. They seem bright to me but I will certainly wait and put a few hundred hours on them before deciding upon more 'tweaks'. What type(s), in your opinion, are a better fit? Guy - I did not check the mfg code, but will tonight. They have a dark brownish base and I believe that they have single 'halos'. I have been scoping the bay for a few days now, but man, those Mullards are in demand! C&S/NOS - As you probably know, the ST-70 has a single adjustable bias pot per channel. I'm very new to this audio field, but would either of you know if this pot is sufficient or should I start looking around to add another? The adjustment is to adjust some voltage to 1.56V on each channel. With this in mind, when I do adjust each to 1.56V, am I 'balancing' out inequities in the tubes? Thanks!

Just about finished with the ST70/PAS upgrades. I understand that most caps (I've replaced all with 'orange drops') take some time to break in. However, I'm noticing that the Tesla tubes I'm currently running are a bit on the 'harsh' side. WRT the easily available tubes....JJ/Teslas, Sovteks, or Svet's, which should provide the best overall tone? Should I 'wait out' the cap break-in period first? Will I notice a significant change as the caps break-in? Finally, originally I had Mullards. Probably never obtain the same sound with the abovementioned tubes. The problem with the Mullards is I busted one so now I have 3. Would it be sacriligious to use 3 Mullards and one JJ? Would this combo still sound better than 4 JJ's? I'm a little apprehensive to just experiment as I've blown it in the past......

Fem.... Using the digital out of the DVD player, I set my 3802 to "auto" rather than DTS or Dolby D or PCMII. Then, upon selecting DTS on the disk-to-watch, the 3802 auto-detects DTS mode and you should see "DTS" on the front panel display of your 3802, and the corresponding LED lit.