henry4841

Maynard taught me to measure plate voltage, when finding dissipation of a tube, from the cathode to plate. You did it mathematically. 🙂 I am sure Eico used an output tube that has a higher dissipation probably more in the 30 to 35W range. I would just be careful selecting replacement power tubes when and if it becomes necessary unless you lower the wattage being run in the tubes. I would sure like for you to look at the schematic of my Eico ST-70 and see what you think about just using the amplifier stage for a new build not using all the other circuits I really do not care for. That and I do not care about not having an original Eico ST-70, just want a PP EL-34 type amplifier.

Redneck county boy like myself way. 🙂

The biggest difference in sound is going to be from a PP, push pull, tube amplifier or a SET, single ended triode. Both sounds are entirely different. I lean towards SET as favorite form. PP is going to sound a lot like all the SS PP amps but probably better for those that love tubes.

Very good point Maynard. I do a lot of listening when seriously comparing two amplifiers. Many, many hours. I have not done it in a long while but that is what it takes for me convince myself there is an improvement or not. Now at this time in my life those kind of things are not that important to me. My worse sounding tube amplifier sounds extremely good to me or I would not have kept it. It would have been torn down for the parts. I like all the tube amplifiers I have decided to keep.

I've heard as much on the net myself. I have use of the Edcor OPT'S already on the EL-34 amp to use but I sure want to install Hammond 125Dse's on my new build. I may just have to fork over the extra $150 or so for those Hammonds. To me they just sound better than Edcors, at least on this Sweetie. Just me probably.

I like this forum with the new rules. Just me.🙂 As far as the deleted thread, all the old timers on this forum knew it was coming.

Some progress, about an hours worth. My GF and I decided to sit on the front porch together for awhile this morning limiting my time in the wood working shop.

My last build consisted of 6 circuits. I just look for active devices when I look at a schematic and consider the components around that active device as a circuit one has to build to make that active part work as it should. Much easier for me to visualize what is happening in an amplifier. This one is more complicated for me to build being as you said some of those tubes are dual triodes or pentodes with separate circuits needed to make them work. I am thinking of using the parts from my Eico ST70 and just make an amplifier using just the amplifier section of the schematic for a build. Still more than I want to tackle but I do need to do something with that Eico of mine. Again great work George.

I have decided this is what I am going to build next. I already have all the big iron and tubes so why not improve the old built EL-34 amplifier I have. It may be a KT-77 tube amplifier or possible an EL-34 built around the EL-34 tubes I recently bought on Ebay. The circuit for either one is the same with possible some changes in the cathode resistor biasing the tube at it's best spot. Right now I am favoring the Tubelab SSE circuit. I like it for it's simplicity and easy build. Other than a constant current circuit added to the input tube the design is a very simple one. There have been many builds done with this design by George Anderson. Started on the wood chassis with cherry wood and plate aluminum in my woodworking shop yesterday. Pictures are forth coming.

The designs for class A and class A/B amplifiers using discrete output transistors or tubes is has been pretty much standardized. There are designers putting their personal touch on the sound they like best into their designs but not so much anymore. Advances in electronics has improved and is still being perfected in the chip amp amplifiers currently being designed and perfected. Discrete component amplifiers are on their way out, for mass produced products that is, and the chip amp topology is on the rise. Still a demand for the old designs for audiophiles though, with some wrinkles with those designers who like to play. What can I say, those newer chip amps sound really good. Instead of tube computers we now use a computer designed around a chip, or as some call them a processor.

The reason I ask is George Anderson and Modjeski likes to run a high voltage and less current in their designs. If my math is correct you are running 30W of dissipation on your tubes. What are your tubes rated for?

Thanks Chief. This is what I was after when starting this thread. Roy's interaction with us. Anybody have any questions they would like to ask about Klipsch R&D this is the place. Good clean conversation of things that really should matter on this forum. Who knows we may get an answer from the Chief every now and then.

A PP amp is too much for me these days. I have only built two of them. How many ma of current you running in those output tubes along with the plate voltage? Just curious.

So you like those orange drops as I do. Sound good to me as well.

I thought as much being Roy asked Guttenberg why he wanted to interview him. Makes me think he is humble as well as smart.

I make my share. The getter on those tubes look really good. Good indication the tubes are still good without having a tester.

I just recently found out the chief participates on this forum. Something you old members already new. That being said there are very few audio sites that have an audio engineer participating on a forum. At least at the caliber of Roy. The Klipsch Chief engineer at that!

Roy blush, come on. Only normal folks do that.

Sonic wise I think they are both the same or at least close enough. I do not believe you will need to change anything else in your speakers to use a composite horn. Me, I'd rather have the metal horn. Old fashioned.

Doubt he has it but why not give him a call. Seems like a really nice guy the few times I have spoke with him.

I have just about decided to rebuild my Tubelab SSE EL-34 amp that I built years ago for another project. If so I will start another thread of the build for those that like such things. Not a whole lot more to say about this premium Sweetie that has not already been said other than I really like the way it sounds and looks. As you can see there are some improvements in appearances that could be made to the SSE EL-34. Actually using Gold Lion KT-77 tubes now. I've made an offer on Ebay for some used old EL-34 tubes. Update, seller took me up on offer. Mine now. Nothing sounds like those old tubes. Supposedly test excellent from seller with 100% feedback rating.

I think it a shame there are not more stores like this. Repairs are not done in house according to the owner but he did say he has one young guy that does repairs to vintage gear for him that is really sharp. No comebacks is the way he phrased it. Hard to leave the store without purchasing something. Caught some of my money Monday!

I wonder what the horn guys at Klipsch are working on now?

I usually just figure the active circuits, the ones around the tubes. I see 7 tubes. I have an Eico ST-70 I started modifying and restoring a number of years ago and put on hold. This week I tested the tubes in it at Classic Audio and to my surprise all but 2 of them tested as new. The other 2 tested 97%. Not having a tube tester and fearing some of them may be bad was one reason I put the project on hold. Now I know I have really good iron and good tubes I am thinking why not just use these parts and build an amplifier using one of my wood chassis with less controls and frills instead of restoring it. The tubes are all original ones and them and the iron are worth more than I paid for the entire amp years ago. Below is the link on this site when I bought this amp. I was in the process doing the Tranola mods Mike Stehr mentions when I put it on the shelf. https://community.klipsch.com/index.php?/topic/196477-eico-st-70/

The Sweetie amp of mine, the personal one I built years ago before this one, was one I always liked the sound of but not one I played that often for a number of years but it was in my regular rotation of amplifiers. There was always something drawing me in to wanting to hear it again. It is the lovely vocals this amplifier makes. None no better of any of my amplifiers. Many of my amplifiers sound as good in the mids but none any better. The sound it makes just grew on me the more and more I listened to it. I figured for what was required for a low cost forum build the Sweetie was the one and I still do believe that. Dollar for dollar it is a design that meets that requirement, low cost, great sound, better than any amplifier I have built. I believe the more you listen to it the more you will like it. That is for anyone that likes the SET sound. Many do not. My preferred sound is a SET tube amplifier. This Premium Sweetie has over $250 in cost just in the iron once you add shipping more than that. Each one of the transformers were roughly $63 apiece and there are 4 of them, OPT's and PS transformers. Then two PS sections using Nichicon 105C caps adds up as well. I do believe it helped improve an already good sounding amplifier.