tigerwoodKhorns

Nah, the 12AU7A is shot. See the picture. Looks like it got a leak in the vacuum. I bought a nice looking but untested on off eBay. Craig said that it doesn't need to be a close match in this position. Craig was very kind to respond and send a manual. He is mostly retired and I appreciate his hospitality. Craig said that you can run the KT150 and bias it but it will pull the transformer to its ragged edge with the heater. Translation, don't run the KT150s in VRDs. Craig said the KT88, KT90 and KT120s are OK. Looking at the cart below this makes sense. So I have a beautiful, just tested, matched and Cryoed quad of Upscale Audio Tung Sols for sale. The boxes look new as well as the tubes. I'll post them in the garage sale section some time soon, but I am interested in a swap for some similar condition KT88s if anyone is looking for KT150s. My mistake will make someone very happy.

Mark, Do you have a pdf of the owner's manual? I emailed Craig but no reply. I really need to learn to bias these things. I think that I have a few bad tubes too so I don't want to turn them on. One of the 12 AU7XA tubes looks done, all of the silver at the top is missing. Do these need to be matched? I found a good deal on an untested single on ebay that might be worth rolling the dice if they don't need to be matched. I always wonder why people sell them. I now have seen several member say that they have had them two or three times. I will store these if I stop using them as I will likely get the itch later on. I don't know if it is outdated, (Probably) but Craig's site says there are only 28 pairs made.

Not the slot port mod but here are some simple bases that I made for a paid of old B&Ws. Just a piece of wood routered on the edge and painted black. You can use this to plug the hole if you ever want to use the rear port again.

If you are willing to cut the bottom of the speakers, you can cut a large hole and build a short base with a front firing slot port. Put a plug in the rear port and if you ever sell them, you can just include a base (piece of wood) with some feet from Partsexpress that can be attached to the bottom if someone wants the rear firing ports.

Quite a setup. Looks like they were bought right before Klipsch stopped offering them. The seller should offer three or one and if the one sells, then he will sell the pair. Wasn't there a long thread on a single Jub recently? This can make that deal happen.

I have Martin DJango XLs that are ported this way. I put a solid wood plate below them as a stand as my room needs the bass extension. The OP does not want to cut the speakers so this really isn't an option. To answer the question, if he extends the port as a wrap around, it will change the tuning. I'm with @wuzzzer, leave them alone. The thing that was not mentioned is that if the speakers are right against the wall, there will be reflections from the drivers. Not optimal at all.

I am not qualified to answer, but the Prima Luna does not look like a compromise to the extent that is can adjust to account for just about anything. Tubes meet high tech. https://www.primaluna-usa.com/primaluna-evo-400-tube-integrated Watch the video above on the KT150s, if the voltages and resistance can be adjusted by a microprocessor in the Prima Luna, where is the compromise? It will optimize for each tube.

@NOS Valves Craig, deleted - Craig, I sent you am email with a few questions on the VRDs.

@henry4841 My understanding is that the Prima Luna will allow you to plug in even mismatched tubes and will adjust itself to correct. I saw a video where Kevin deal mentioned this stating you don't even need to match the quads and you can run from the EL34 up to the KT150. I really appreciate the info that you provided. I took some electronic courses in undergrad 30 years ago when I was getting my engineering degree and really want to be knowledgeable on this. To cut to the chase, I can run the KT150s but will not get the full power output from them. That is fine, but I imagine that there is a range on those graphs where the tube is designed to work and if you get outside of that area in any direction it is not ideal. Here is a great video where he goes through the simple calculations to get full power form the tubes. About 14 minutes in he shows that if you run at lower current than as designed, the curves are steeper and it is easier to clip moving down the load line. I will not pretend to completely understand the chart, but I have seen many similar charts where you move out of the optimal range and things do not work correctly, safety factors decrease, etc. Here is an initial question. This chart is from the video. If the VRDs run at 1.6A heater current, is that too low as it is below spec? I just noticed that he does mention this at the end of the video. The other items are all stated as 'max' voltage current and dissipation so I assume that these are OK so long as everything is run in a balanced fashion. The person who sold the VRDs had used KT150s and loved them, that is why I picked up a quad of them. I should have done a little more research on them but they are not that easy to find so I jumped when they went on sale. Here is a good link that I will need to study, but unfortunately I don't have the specs for the VRDs. https://robrobinette.com/Drawing_Tube_Load_Lines.htm I'll ping Craig on this one.

There was another one. A single.

I think the VRDs are optimized for KT88s. This guy is gettign 80 wpc but these might be custom amps. https://www.audiocircle.com/index.php?topic=127465.0 Do you have a link to a tutorial as to how to read these graphs?

There were some on sale here recently (like the last year or so). Do a search.

These look like a steal. I just can't justify any more speakers.

Old thread. Need some info. Can anyone supply a scan of the VRD owner's manual? I am new to this. I bought some KT150s. I understand that they will only produce as much power as the amp will allow, but are they in the correct range if used in the VRDs? (will the VRDs provide enough voltage to drive them properly). I'd prefer to underdrive them to make them last longer, but I need to understand how this works. @tube fanatic I need a lesson in tube curves and more info on VRDs. Thanks.

Down to $175, $100 might take them.

You have to post some pics.

You have KLF 20s in an RV?

I think he is referring to one of their RF surround speakers that are kind of a triangle.

Mark, Glad to hear that you are doing so well and thank you very much!

Do you know how to ping him? My @RealMarkDeneen didn't work. Ok, now it works.

I saw a video last night by Steve on the S300s. Here is a video on the ones for sale. Looks like these are something very special. Nice components. I like using this type of bookshelf for 'computer speakers' in an office system. Steve Gutenberg really likes these and he is a big Klipsch guy. GLWS.

I don't know my tangents at all. For $225 though it is a nice deal for someone. Wish I had found these when I was a teenager for $225 in 1985 dollars.

Go get 'em. Really nice deal and they have been for sale for quite a while. https://lasvegas.craigslist.org/ele/d/las-vegas-klipsch-tangent-series/7567487161.html

@RealMarkDeneen Did the Merlin schematics ever get posted?

Oh man, you stop by and class this place use and now I have to go get my dictionary out. Good to see you!