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I went to pick up a speaker and an amp. Look what I got!

hammr7 said:
If you keep the "flame linear" 400, make sure those fans are always working. The amps themselves are powerful workhorses, but had a reputation of getting really hot. The 700s were worse than the 400s at burning up, but both originals came without fans, and both models got horrible reliability reputations. All they ever needed was after-market fans.
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Thanks, I will do that if I keep it. First I have to undo the changes the previous owner had made.
 
I powered up the PL400 on the weekend. Seems I have very low output. I cleaned it up and undid the mods. I've even found someone local who will build a nice solid walnut cabinet for it. He has the amp for the moment so he can fit it to the cabinet. Once I get it back, off the amp goes to my tech.

As for the speaker drivers, I have a pair of EV VMRs on the way. I am studying right now on how to build transmission line cabinets for them. At the same time, I want to try out a few ideas I have. When I was a kid in the mid 70s, I decided to replace the crappy speakers my all in one stereo came with. Because I was only 13 or 14, I used scrap plywood from our house my dad was building, and researched speaker design. I ended up going with the best 10 inch dual concentric speaker radio shack had. And I built a pair of bookshelf sized speakers (I needed small to fit in my small bedrooms shelves). I only realized about 10 years ago that I had built a pair of transmission line speakers! It makes sense in hindsight.

So far, from all the quick and dirty modeling I've done to date, I will need Cornwall sized cabinets to do a proper job. I am trying to model them as per the Interface D cabinets because I like the look. And I think I am going to install the SP15As down-firing. According to my ratio calculations, that makes them pretty close to Cornwalls in size. The Mid and tweeter are going to install on the top front of the cabinets and they will be the only part of the speakers covered in grill cloth. The transmission line port is also going to come out the bottom. The insides will be quite different from the Interface D. From what I can tell, the Interface D uses simply a port. Mine are going to use internal panels to direct the sound through the bass box. I am waiting for the VMRs to arrive so I can measure how deep they will cut into the top front.

So it seems this last audio purchase is a gift that keeps on giving! I have a project to help keep me sane into this new lockdown, and most of the expensive parts are already acquired! I read up on the work a fellow over at DIYAudio did. Impressive stuff! And then, while searching for Interface D's I saw a link to his speakers on eBay. He sold them for some nice coin. I asked him why he sold them, and it was because he was starting a new project, and he didn't like the speakers. He said they took away from his listening pleasure. His replacement speakers are a completely different concept and very nice. I'll never do that caliber of work (it was really professional), but I can simplify my life by making my work easier. And I have to keep in mind he found they hurt his ears. I'm thinking this must be that harshness the ST350A is known for, but I thought that issue was addressed in the interface d. My thought is he used a different crossover design and maybe eliminated the EQ. Anyway, I do have to plan for the possibility I won't like it either. Assuming it is the tweeter, I can have a plan b for that.
 
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Awesome. Keep it going. I don't think the st350'a's are Harsh at all. in fact a bit limited in the extreme highs.
Not that I can hear them anymore anyway .
 
Nyjblbob said:
Awesome. Keep it going. I don't think the st350'a's are Harsh at all. in fact a bit limited in the extreme highs.
Not that I can hear them anymore anyway .
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That made me laugh!

I'm glad to hear positive things about the ST350As. My gut feeling is that he deviated from the design somewhere, and that is why he didn't like them. I will also be deviating from the design, but I'm going in there eyes wide open. I still have lots of research to do. Then I need to plan out the cabinets, and find a cabinet maker. I'm hoping the guy I am currently working with for the PL400 will work with me on the speaker cabinets.
 
Best of all All EV, just the woofer and cabinet size is not the same as the interface D's. I bet any good EQ will work to balance everything
 
I actually have a decent EQ here, and I will be playing with that. I also may invest in a DSP to assist in designing my crossovers.

That's what I love about AK. There are so many ideas that people provide on approaches to take when we are in unfamiliar territory. I was seriously just going to sell the drivers, but I love the design on the Interface D. It appeals to my eyes, and my wifes! :thumbsup:
 
I found a couple of EV Interface B EQs. They should arrive soon. My understanding is there are 4 resisters to change to make them equivalent to the Interface D EQs.
 
Nyjblbob said:
Nice! they should be quite the bargain giant killers!
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I hope so! It will a be very interesting project. I have also started developing a relationship with a carpenter who is building a wooden case for the PL400, so the cabinets may be moving closer to reality. We shall see!
 
BilboBaggins said:
I found a couple of EV Interface B EQs. They should arrive soon. My understanding is there are 4 resisters to change to make them equivalent to the Interface D EQs.
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If you need some pictures of the PCB from an actual Interface D EQ, i'd happily open up mine and send them to you. I was heading down the same road you are now but got lucky and found a model D EQ for my speakers
 
bigcaddy64 said:
If you need some pictures of the PCB from an actual Interface D EQ, i'd happily open up mine and send them to you. I was heading down the same road you are now but got lucky and found a model D EQ for my speakers
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That would be fantastic bigcaddy64! Thanks, that would help a lot!
 
Here are the pictures, Bilbo. If you need any specific values of anything, just let me know and I’ll get them for you.
 

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bigcaddy64 said:
Here are the pictures, Bilbo. If you need any specific values of anything, just let me know and I’ll get them for you.
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Thanks bigcaddy64! This is great! I'll review it this weekend, but I think you got good shots of the resisters. I'm hoping the Interface B EQ arrives next week sometime.
 
On the topic of the PL400, I heard from my carpenter this afternoon, and he has the wood, and is expecting to finish the cabinet next week. Then I can bring the amp to my tech. This is moving along nicely on all fronts!
 
It's great to see that things are working out well for you currently and hopefully your project will continue in the same manner. Hopefully your satisfaction with the completed project will be very gratifying!
 
doctorolds said:
It's great to see that things are working out well for you currently and hopefully your project will continue in the same manner. Hopefully your satisfaction with the completed project will be very gratifying!
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That is one thing that worries me. No matter what, I am going to pay a fair amount for the cabinet materials and work. If I don't like them, what do I do? :dunno:

In that vein of thought, if I design it right, I should be able to re-purpose a good part of the cabinets. At that point, I could emulate the Cornwall bass portion and hopefully be happy. I just need to research some more, and I will make a decision on that. At the moment, I haven't settled in on one design.
 
I'd say try to experiment with the current cabinets if possible??? Were you able to get the T/S parameters for the drivers? If not, do you have a DATS test unit from Parts Express? It's fortunate that the crossover parameters for some driver's can be found in some of the threads here on AK. In the event that your not quite happy with the initial design/crossover you can manipulate as needed to obtain satisfactory results. In my opinion EV driver's are a good choice for a project, and I am hopeful that you are successful with your project. Best of luck to you sir!
 
Nice find on the EQ's I saw those also,

BilboBaggins said:
I am going to pay a fair amount for the cabinet materials and work
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Wondering why a solid material was used versus veneer which would usually be the route to go due to
cost and wood expansion issues?
 
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