Hi Bob,
I designed these speakers specifically for this amplifier. They are about 98dB efficient. It is a 2-way bass-reflex design using the Eminence Deltalite II 2510 woofer and the Ciare 1.38TW horn tweeter. I designed the crossover with a Zobel network for the woofer and a compensation circuit along with required attenuation for the horn tweeter. They have a very live sound, actually they are awesome. It's like the performers are in the room with you. They are pretty flat all the way down to about 48Hz. The first set I built uses the traditional "monkey coffin" design, however I have redesigned the cabinet to be a more contemporary floor-standing version. I have not built the floor-standing design yet, but it should be exactly the same just not needing a stand to elevate them to ear level. I hoping to have the new version built in a couple of months as time allows. Let me know if you are interested.
I want to add that these loudspeakers seemed to take about 50 hours or so to "break-in". The low-end and tightness improved dramatically after running these for a while at relatively loud volume.
Scott
I designed these speakers specifically for this amplifier. They are about 98dB efficient. It is a 2-way bass-reflex design using the Eminence Deltalite II 2510 woofer and the Ciare 1.38TW horn tweeter. I designed the crossover with a Zobel network for the woofer and a compensation circuit along with required attenuation for the horn tweeter. They have a very live sound, actually they are awesome. It's like the performers are in the room with you. They are pretty flat all the way down to about 48Hz. The first set I built uses the traditional "monkey coffin" design, however I have redesigned the cabinet to be a more contemporary floor-standing version. I have not built the floor-standing design yet, but it should be exactly the same just not needing a stand to elevate them to ear level. I hoping to have the new version built in a couple of months as time allows. Let me know if you are interested.
I want to add that these loudspeakers seemed to take about 50 hours or so to "break-in". The low-end and tightness improved dramatically after running these for a while at relatively loud volume.
Scott
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on paper, yes
and at a certain frequency
look at 500hz, or so
then ususally a different picture
I didnt even mention BSC
baffle step compensation
which means SPL loss below 500hz
compensation is done by attenuating above 500hz
subtract that, and it could be even lower than 95db
but I didnt
a calculator will also tell you this
even much bigger woofers often ends at 96db
does it matter
I dont know
but it is partly about whether a speaker sounds 'thin' or 'full'
maybe you compensate some by using tube amp, etc
and not to forget the bigger front baffle
Thanks for your comments.
I did not use a BSC circuit in the design of these loudspeakers. Based on my calibrated measurements and frequency response testing, this is not required and would only offer detrimental effects.
I did not use a BSC circuit in the design of these loudspeakers. Based on my calibrated measurements and frequency response testing, this is not required and would only offer detrimental effects.
KT88 SE Master Kit
After reading the threads on the single ended KT88 amplifier project, I decided to purchase the KT88 SE master kit from scitizen17 and received it this past week. Scitizen17 shipped the kit promptly and the kit arrived safely.
Although I can’t start building for several weeks, I pulled out all of the parts and was impressed as this kit appears to be very well-engineered. I’ve read through the instructions and they appear complete and seem to move straight through the process. Parts quality appears excellent, and the overall quality of construction is excellent, especially considering the price. What you get in this kit, for the money, seems like an extremely good value.
Also, I really like the tube rectification aspect and the use of the 6N1P-EV driver tube. It looks like I will end up with a professional looking product and have a lot of nostalgic fun in the process (reminding me when well-engineered kits were common place in the 1960s).
After reading the threads on the single ended KT88 amplifier project, I decided to purchase the KT88 SE master kit from scitizen17 and received it this past week. Scitizen17 shipped the kit promptly and the kit arrived safely.
Although I can’t start building for several weeks, I pulled out all of the parts and was impressed as this kit appears to be very well-engineered. I’ve read through the instructions and they appear complete and seem to move straight through the process. Parts quality appears excellent, and the overall quality of construction is excellent, especially considering the price. What you get in this kit, for the money, seems like an extremely good value.
Also, I really like the tube rectification aspect and the use of the 6N1P-EV driver tube. It looks like I will end up with a professional looking product and have a lot of nostalgic fun in the process (reminding me when well-engineered kits were common place in the 1960s).
My First Tube
With no idea of building a tube amp and awakening interest in tubes I stumbled over Scotts KT88 SE thread.
I followed over a few months and more and more I had the feeling..
...that this would be a good project for my first build.....
I started thinking about the details and ordered the basic kit from Scott.
I ordered the basic kit because I knew I have enough woodwork skills to build the chassis at a self-help workshop for woodwork next to my home.The transformers I wanted to source here around, even because the shipping costs would have been very high too.
My experience with the chassis....
I build a frame from solid oak which was real fun to do...
I had to get longer speaker terminals as the frame is 23mm thick
so I choosed CMC-858-L-CU-G.
Even other RCA jacks...these are Neutriks NF2D-B.
For the volume control I milled out some wood from the inside and ordered a knob with a little more depth than the one from the kit.
For the topplate I took 2mm aluminium, but I can recommend even more because the transformers (my ones) are so heavy that the plate warps a little bit down.
For drilling the topplate I took Scotts setchassislayout.pdf modified it to the real size, printed out a 1:1 template and fixed it on the topplate for drilling and cutting.....very recommendable!!!!!
Only if your transformers have the same cutouts and size!!!!
To find transformers for a reasonable price and especially OPT's with 5K and siutable power was actually not easy....I sourced mine from vt4c.com with the cheapest shipping option by land that should take 2months + , but they came after 6weeks.
All Mars LM-330B-EU Power (which is a monster of 7kg)
LM-9906c Choke
and 2x LM-5K-25G OPT
The OPT'sare standup so you don't need cutouts, only a few holes...
and the power and choke have nearly the same size and cutouts like the setchassislayout.pdf shows.
Building the amp....
Scott did a very good manual!Very detailed and easy to follow!!!
I had very few questions although my little experience.
It was real fun to build this amp....
I have average soldering skills but I'm a good homeworker.
The only support I needed when I wired the power transformer as the Mars one has different connections.........but no problem with Scotts help.
For wiring I took my own stocks of wire about 1mm pure silver in teflon tube (from an old speaker cable project), 1mm UPOCC teflon for the heaters and CONNEX BL-Ag "balanced" interconnect cable for input to volume control (very good cable)
The tubes I got from Ebay EH 5UGB rectifier, Russian NOS 6N1P-EV driver and I shot very cheap matching pair Shuguang KT88.
I was really exited to hear the amp the first time, especially because I hoped the 10-15Watt will be enough for my 89dB speakers (KEF Q5)
.....but wow...fantastic sound and enough power even in triode mode (I have the feeling it's the better sound too)
A few pics.......
With no idea of building a tube amp and awakening interest in tubes I stumbled over Scotts KT88 SE thread.
I followed over a few months and more and more I had the feeling..
...that this would be a good project for my first build.....
I started thinking about the details and ordered the basic kit from Scott.
I ordered the basic kit because I knew I have enough woodwork skills to build the chassis at a self-help workshop for woodwork next to my home.The transformers I wanted to source here around, even because the shipping costs would have been very high too.
My experience with the chassis....
I build a frame from solid oak which was real fun to do...
I had to get longer speaker terminals as the frame is 23mm thick
so I choosed CMC-858-L-CU-G.
Even other RCA jacks...these are Neutriks NF2D-B.
For the volume control I milled out some wood from the inside and ordered a knob with a little more depth than the one from the kit.
For the topplate I took 2mm aluminium, but I can recommend even more because the transformers (my ones) are so heavy that the plate warps a little bit down.
For drilling the topplate I took Scotts setchassislayout.pdf modified it to the real size, printed out a 1:1 template and fixed it on the topplate for drilling and cutting.....very recommendable!!!!!
Only if your transformers have the same cutouts and size!!!!
To find transformers for a reasonable price and especially OPT's with 5K and siutable power was actually not easy....I sourced mine from vt4c.com with the cheapest shipping option by land that should take 2months + , but they came after 6weeks.
All Mars LM-330B-EU Power (which is a monster of 7kg)
LM-9906c Choke
and 2x LM-5K-25G OPT
The OPT'sare standup so you don't need cutouts, only a few holes...
and the power and choke have nearly the same size and cutouts like the setchassislayout.pdf shows.
Building the amp....
Scott did a very good manual!Very detailed and easy to follow!!!
I had very few questions although my little experience.
It was real fun to build this amp....
I have average soldering skills but I'm a good homeworker.
The only support I needed when I wired the power transformer as the Mars one has different connections.........but no problem with Scotts help.
For wiring I took my own stocks of wire about 1mm pure silver in teflon tube (from an old speaker cable project), 1mm UPOCC teflon for the heaters and CONNEX BL-Ag "balanced" interconnect cable for input to volume control (very good cable)
The tubes I got from Ebay EH 5UGB rectifier, Russian NOS 6N1P-EV driver and I shot very cheap matching pair Shuguang KT88.
I was really exited to hear the amp the first time, especially because I hoped the 10-15Watt will be enough for my 89dB speakers (KEF Q5)
.....but wow...fantastic sound and enough power even in triode mode (I have the feeling it's the better sound too)
A few pics.......
Attachments
Scott,
I' ve seen your pictures from inside, thanks for posting it again.
I was interested in Gregs assembly, since he stated that it was his first Tube.
I was just interested, if his (IMHO) outstanding craftsmanship on the chassis also goes as far as your clean work under the chassis.
Me, for sure, would never have the patience to work as accurate as you 2.
Ciao
Christoph
I' ve seen your pictures from inside, thanks for posting it again.
I was interested in Gregs assembly, since he stated that it was his first Tube.
I was just interested, if his (IMHO) outstanding craftsmanship on the chassis also goes as far as your clean work under the chassis.
Me, for sure, would never have the patience to work as accurate as you 2.
Ciao
Christoph
Well after years of listening to tube amplifiers I decided i wanted to try my hand at building one. I searched over dozens of posts and websites looking for the best kit. I wanted to do as much of the work as I could, but it being my first time I needed some guidance. I came across Scott's kit and was amazed. It had everything I needed. Free rein on the chassis and the assembly, without the hassle of sourcing the bulk of the parts. The manual that was included in the kit was perfect. I was able to follow it step by step as a first time builder with no problems. You can really tell he took his time working out all the details. I'll post a full review of the audio quality when I get a chance but I can say that the sound is amazing so far. It is dead quiet. If you are on the fence about what kit to buy, I highly recommend this one. Here's some pictures of it.
Attachments
Finally got the time to put together the KT88 SE master kit from scitizen17.
I had been looking around for the next step up from the flea watts and chip amps and looked at a number of kits.
This kit seemed to fit the bill and my price point.
Overall, sweet experience.
Kit showed up promptly and was well packaged.
Component quality, attention to detail and instructions were all very good.
Sound so far is excellent, quiet and detailed.
I would like to thank scitizen17 for the time and effort put into making quality kits like this available.
I had been looking around for the next step up from the flea watts and chip amps and looked at a number of kits.
This kit seemed to fit the bill and my price point.
Overall, sweet experience.
Kit showed up promptly and was well packaged.
Component quality, attention to detail and instructions were all very good.
Sound so far is excellent, quiet and detailed.
I would like to thank scitizen17 for the time and effort put into making quality kits like this available.
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