tube fanatic

Sorry Cap, but your arguments are only partially correct. But, this is not the venue for such a technical discussion. If I can find time during the week between Christmas and New Year, I will start a thread on DIY Audio and discuss it with you there, where it belongs (I assume you are still very active on there as well). We can post a representative amplifier and analyze every factor from input to output and look at what happens everywhere. Then, we can have the input of other EEs to really spice things up a bit! Maynard

Captain, did you measure any phase shift in your breadboarded Sweetie with fb? Some listeners seem to be able to hear it with certain music so I side with Henry in not using any with SETs. As far as simple vs. complex music goes, I like to use large choral works to make some evaluations. In years past I compared the tube amps with SS units having virtually no distortion (but large amounts of nfb of course) and heard little or no difference on such selections. Congested sounding vocals were still that way with the SS amps. At this point my conclusion is that it really doesn’t matter how the amp measures if the listener doesn’t like the sound. So called “accurate” reproduction is not always the most pleasing to listen to. There’s a reason why so many use the tone controls on vintage amps and preamps so liberally. Maynard

I am definitely in Fido’s realm with listening levels. Years ago we had a discussion on here about what I termed the “magic listening level” at which the room contributed little and at which music just seemed right. I recall that the consensus was that lower levels were considered best. I have always contrasted my habits with those of “the guy down the road” whom I have spoken of many times. His usual level is in the 110-115 db range from his CWs. He is a professional drummer (and retired music teacher). Amazingly, he isn’t deaf. The flea power folks I designed amps for all preferred small room, near field, systems and low listening levels as a means of being drawn into the music. Maynard

My wife makes me watch this whenever I get into a crabby mood (as all can imagine, this rarely happens 😄): https://youtu.be/ZbZSe6N_BXs Maynard

I am concerned that you found high distortion from the Sweetie. At 250mw it should be very low. Can you take measurements at the 6Y6 grid so we can see what the driver is doing? If that measures high, try pulling its cathode bypass cap to get some current feedback and measure again. It will drop the gain, but the 6SJ7 has so much it should not be an issue at all. Also, if your signal generator can provide output of a solid few volts rms, you can try driving the 6Y6 grid directly and take that measurement as well. Maynard

I can’t get enough of Dailey & Vincent. They play faster than I can think, especially Jeff Parker on the mandolin: https://www.youtube.com/watch?v=KshIfJSqcHU Maynard

I recently read an interesting article about the carnivore diet. Can you describe your typical daily meals? Are you eating cafo meat and, if so, do you have any concerns about all the antibiotics and hormones you are ingesting? Maynard

Close Mark- November ‘58! Maynard

I may have to try something like this! Maynard

Aside from having an extra tube filament to enjoy looking at I don’t see any need to add the expense of another tube which will eventually need replacement, and another socket. Modern SS diodes can typically handle a 100-200 amp surge so that is a non-issue, and I find that the power xfmr impedance is sufficiently high to serve as a peak current limiter. I have never had a power xfmr fail due to peak current issues. The component which takes the hit is the fuse and often needs to be a slow blow type. Another advantage of SS rectifiers is that they allow the use of very large value input filter caps so that ripple can be brought down to negligible levels very inexpensively. Two caps and a resistor can create ripple values which can only be duplicated by using a more costly choke with a tube rectifier (the value of the input filter cap is generally very low to protect the tube). When designing new equipment it comes down to a matter of taste.

Can you find out who did the servicing and exactly what was done? Owning vintage gear can be costly if critical components were not replaced resulting in failure. Maynard

I can’t agree with this. The extra voltage on the tubes may exceed the rated limits and, in addition, could shift the operating point of the tubes resulting in different distortion characteristics which are not desirable. Maynard

You need to be careful. The 5U4 filament draws 3 amps while the 5Y3 draws 2. If the filament winding of the power xfmr can’t handle the extra current you could have a problem. Also, equipment designed for a cathode type rectifier may use electrolytic caps which cannot handle the peak voltage they would see at initial turn on with a filament type. Best to stay with the recommended type unless you are sure about specs. Maynard

Here are the measurements in case anyone missed the tab at the bottom of page 1: https://www.stereophile.com/content/western-electric-type-no91e-integrated-amplifier-measurements Not overly inspiring given the price point but I bet it would sound very nice into K-horns! Maynard

Many were skeptical that this amp would ever be brought to market. Well, here it is: https://www.stereophile.com/content/western-electric-type-no91e-integrated-amplifier Maynard

Dave Harbaugh was as creative as Rodrigues and his cartoons appeared in many electronics magazines. They cover a variety of topics, so enjoy! Below the featured cartoons are links to many more. https://www.rfcafe.com/references/popular-electronics/hobnobbing-with-harbaugh-mar-1963-popular-electronics.htm Maynard

Please see my comment in the thread on entry level tube recommendations. Regardless of budget, the only way to know what will satisfy your listening needs is to hear the equipment in your system. Maynard

Unfortunately, recommendations don’t usually work out. The only way to make a judgment is to audition an amp in your own system. Perhaps there are forum members in your area who have tube gear which they can bring over. Lacking that, buying from a dealer or company which allows returns (like Decware), is another possibility. Remember, your hearing is unique and only you can judge what will provide the greatest listening enjoyment. Maynard

Many of us can relate to this (looks like my den!) Maynard

Out of curiosity, did you have visual training as a child in an effort to gain binocularity? Do you also have amblyopia? There have been some really great results obtained by developmental optometrists in that area. In fact, some folks who had strabismus surgery as adults have achieved a degree of stereopsis after such training. It was once believed that after age 7 or so the visual system was too matured to allow any improvement, but that has been proven to be incorrect. Sorry to dilute my own thread but this is an interesting subject area. Maynard

You are fortunate not to have experienced recordings in which an entire orchestra is shifted to one side or the other, or listening at asymmetrical distances from the 2 speakers caused unpleasant imbalances. As far as the analogy to binocular vision goes, it is indeed possible to experience depth perception monocularly. In fact, I have known quite a number of individuals who are essentially monocular due to amblyopia, strabismus, or loss of an eye who can gauge depth remarkably well. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4934676/ Similarly, even if you were to occlude one ear(obviously not the case when listening to a single speaker with both ears), it is still possible to experience depth and localization due to sound intensity and reverberant cues. With 2 ears, listening to a single speaker source, it is quite likely to experience “depth” or whatever you want to call it. In any event, we all prefer what we like most. Trying different experiences will sometimes allow us to change our preferences. Maynard

I try to find something to laugh about every day. In this sick world it is very therapeutic. My laugh for today came from this scene from the movie Uncle Buck, my third favorite movie of all time (Animal House and Fast Times at Ridgemont High are #1 and #2). My sense of humor has not changed since I was about 11 years old. I guess I should be glad that one part of me has not aged with the rest… https://www.youtube.com/watch?v=5ibO5kob3OQ (And I just told Henry that I won’t venture out of the tubes section!) Maynard

The voltage drop across a tube rectifier will depend on the voltage applied to the plate(s) and the current draw. You can get an idea about this from the data sheet which shows the expected DC voltage available at the input filter cap (most equipment uses a capacitor input filter - choke input filters have different parameters). An example is below for a 5Y3. The voltage drop for solid state rectifiers is insignificant in high voltage applications. There are some other considerations for the latter as well including the value of the input filter cap. Maynard

Those new to the forum are no doubt unaware that I returned to my roots some time ago and now listen exclusively in mono. Constantly fussing with channel balance (due to recording issues, room acoustics, and asymmetric frequency response of my ears), and being locked into a “sweet spot” became a chore. So, having forgotten how it would be, I decided to give mono a try and could not believe how glorious it is! No sweet spot and, with a speaker in the corner, amazing dispersion into the room. I use a single RB-51 series 2 since my den is on the small side. I recommend that anyone who is frustrated by the difficulty of attaining perfect stereo give this a try. Using a tiny mono tube amp to drive the speaker has really taken me back to the late 50s/early 60s. A couple of years ago I posted a very humorous article by Vincent Gallo in which he extols some of the other virtues of mono listening. It is worth reading! https://community.klipsch.com/index.php?/topic/194365-vincent-gallo-on-mono-listening/ Maynard