[JoshK]

Bass bins for my speaker project have been designed.  Modeled and drawn.   I am sitting here trying to figure out what is the best way to build it.

I decided on JohnJ's suggestion for a TD15X in a 5cu.ft. enclosure with a 3" x 16" slot port 26" long (wrapped up the back).  Except, I decided on a twist.   Instead of a standard slot port, I am going to do 4 1.5" x 4" slots on each side of the cabinet, Onken style.  The outer dimensions come to 23" x 22.5" x 31".  Not too bad.  I can stuff the ports if I decide I don't like the ported tuning, which would create an aperiodic tuning that would be pretty close to ideal, I think. 

This gives a 28hz tuning and from memory the -3db point is upper 30's and -10db in mid 20's.  95db/w for most of the passband. 

I am thinking of using the MT baffles (shown previously) in semi-open baffles above this.  I am considering toying with the muffler idea that MBK was demonstrating in diyaudio's cardiode thread.

#2 I was painting my TT plinth.  Its starting to look semi-decent in a gloss black finish.  It needs some more layers and lots of sanding.

#3 tweaked the Aikido PSU and fired up the Aikido preamp for the first time.  Unfortunately, B+ came in way above predicted at 400V (was suppose to be 300V).  I must have plugged the wrong DCR for my chokes into PSUDII.  Don't know how it would be that off.  Tranformer was actually measured and measured values plugged in.   

[GBB]

Josh,
Regarding the Aikido PS - is it possible that the tubes aren't drawing as much current as you're expecting?  That's the only thing that I could think of that would cause you to be that much higher than expected.  Unless you've wired things up really wrong.
What type of PS are your using?  Choke input or capacitor input?

---Gary

[JoshK]

cLCLC.  Yeah, I really need to measure more but I started on something else. 

[GBB]

cLCLC. 

I assume that the small "c" means that you are tuning the power supply voltage with this "c" and that the target voltage is in between what one expects for an inductor input filer and a capacitor input filter.  I've never had good luck predicting the exact value needed for this type of filter - you just need to experiment until it hits your target.

---Gary

[JoshK]

That's it.  I was just surprised at how far off it was.  I know the Hammonds run high because of the 115V primary, that adds some.   Still, that is 33% high. 

The good thing was that ripple was immeasurable on the 600V range of the DMM, which it should be.

[tdangelo]

I recently swapped out my Usher BE-20 stock crossover with some made by Danny Richie.  Nice guy to work work.  The new networks use very high quality part and build quality is very good.  Although the 20's sounded fantastic with the stock xovers they've gone up a level or 2 in refinment an smoothness.  No more phase issues that really bugged me - bass is pefectly balanced and refined - before bass was just to strong and not as well defined.  The platinum bypass caps will take many more hours of burnin but even at 15hrs they sound very nice.  I'm happy so far.  The job took about 5-6 hrs - it wasn't to difficult but just tedious.  At this point I think it was worth it The lower tweet xover make the tweeter a little more alive but not to hot or shrill - the midrange now produces more vocals since it also plays lower - it sounds much better with less voice out of the woofers. IN all it was a good worthwhile upgrade.
 
Tony

[SET Man]

I am not really a tweaker. 

Here is my recent project.  ...

Cheers
--Levi

Hey!

   Whoa! When dose Levi turn in to a soldering iron swinging DIYer? 

   I thought he only buy factory made brand name audio components and open only just to take picture of the inside.

   Anyway, nice works there and have fun

Take care,
Buddy

[jules]

Currently working on:



These boards are part of, what will eventually be a 45W X 2, pure Class A SS amp and pre-amp. It's a DIY from audio-gd and a big project. I might post the build story here as a topic in its own right.

Bluesky: nice project and great dedication to a well designed piece of research. I am guessing that you are holding back on the grounds that you'd be doing A-B testing [banned here on the grounds of generally becoming tedious] but I hope you'll give us your results as your approach is anything but superficial.

Jules

[bluesky]

Hi Jules

Much appreciated comments.  I think it would make for a very interesting project but realised that the blind testing was contrary to existing rules.  It is very much a matter of seeing if the premium parts that I am sure we all buy as audiophiles, really do make much of a difference.

I am guilty of buying the occasional expensive cap or resistor and I "think" they make a difference.  However by the time I get to listen to any changes the time delay makes it difficult to work out just how much difference such parts made.  Hopefully I could provide an overview of the results without causing too much distress to anyone.

Bluesky

[jeffdavison]

Almost done, just have to do the input wiring from the RCA's to the selector switch.

Here's some teaser shots, later I'll post some "up-skirt" shots when done.

My variations are dual rectifed cLCLCRC power supplies ( two p.s.'s but one trans),  and some NOS tubes I had laying around... GZ34's, KT77's and a 421a.

I built the cahssis to match the DC S.E.T.'s I built earlier this year.

JD

[BillB]

 

And a WE 421a ta boot.

My pre is jealous and it is still just parts. 

[jeffdavison]

Bill,

the pre is up and running. Sounds very nice... still burning in. Dissapates ALOT of heat! more than my SET's.

Since your inthe Atlanta area... I surmise this as the link from you signiture says your based here (home of the $200 etc..) I'll extend an open invitation if you'd like to drop by and audition it.


Jeff

And a WE 421a ta boot.

My pre is jealous and it is still just parts. 

[BillB]

I would love to!

[JoshK]

Had a couple days off around the weekend.  Mostly worked on the new bathroom and study, the garden, a new kitchen faucet, but today I decided to play with a tube project.  I had received a Tubelab SE board two weeks ago and got most of the parts in last week, so I stuffed the board today.

The Tubelab SE, in case you aren't familiar, is the DHT SE amp with the powerdrive circuit, its not the same as the SimpleSE which uses a more traditional driver and audio pentodes.  I wanted to build another SE amp for comparison and was always intrigued by George's powerdrive circuit. 

I plugged in my JJ 300Bs to see how they fit.  Boy are they a tight fit!  I have about 1/4", if that, between the glass of the two triodes. 

I have a pair of Transcendar 3K 10W OPTs, a James 5H/200mA choke, a couple different power transformers to choose from, and a 85uf motor run cap for the B+ filter.  That about rounds up the choices.  Nude russian teflons for coupling caps.

[Mariusz]

Hi Josh

Will we see (hear) these eye candy at your place at upcoming "Mini-Rave" ???
If so, what speakers are (will you be) you using with those babies ?

Mariusz

[mgalusha]

I rebuilt my preamp last week. Put in a Swenson regulator and a CCS on each half of the 6SN7 gain tube. Also installed a LDR attenuator, essentially the Lightspeed attenuator but built into the chassis. Supposedly the PS for the LDR attenuator is somewhat critical so I used ultrafast recovery diodes followed by a small 'lytic then a common mode choke, a big cap and feed that into one of the little miniVreg's from AW DIY left over from when I was hacking the DCX's. It has another LC filter and uses a Linear LT1763 reg chip. Works out to a nice quiet supply for the LDR's. Also some lovely polypropylene film bypasses some small panasonic FM caps on the input and ouput of the reg.

The regulator and CCS mods were a big step up and adding the LDR attenuator was also very nice and totally worth the time and expense, which is actually pretty low for the results. This replaced an ALPS pot. Big thanks to Josh K for hooking me up with the Swenson/Pimm regulator boards. 

[JoshK]

Hi Josh

Will we see (hear) these eye candy at your place at upcoming "Mini-Rave" ???
If so, what speakers are (will you be) you using with those babies ?

Mariusz

I was hoping maybe you could bring your Omegas, or do you still have a pair of Omegas?  Otherwise we are stuck with my 89-90db 4ohm MTMs. 

I am not sure if the TubeLabSE will be up and running by the mini-rave as I wanted to get started on my woofer bins.  If it will be running it will be on a bread board, but that might be doable since I don't need to do much apart from clip lead some wires to my transformers and a couple connectors.

[Mariusz]

Hi Josh

Will we see (hear) these eye candy at your place at upcoming "Mini-Rave" ???
If so, what speakers are (will you be) you using with those babies ?

Mariusz

I was hoping maybe you could bring your Omegas, or do you still have a pair of Omegas?  Otherwise we are stuck with my 89-90db 4ohm MTMs. 

I am not sure if the TubeLabSE will be up and running by the mini-rave as I wanted to get started on my woofer bins.  If it will be running it will be on a bread board, but that might be doable since I don't need to do much apart from clip lead some wires to my transformers and a couple connectors.

Do not go bananas over the Rave. Do what you need to do first. If you need anything specific just let me know.
As to speakers - do not worry Josh, we will think of something that will work with whatever.
Omegas are still in my possession and are not likely to go anywhere soon.
We can have those or I can bring over some "prototype" bipolar speakers which I am still working on. They still need some tuning but I am very happy with the results so far. They are small floor-standers with quite amazing clarity and soundstage. The lower bass is not the last word in seismic stimulations but tuneful enough for average music-lover.

I know that you have a lot on your plate and time is limited, so just let me know when you'll be ready and what can I do to help.

Mariusz

[rajacat]

Hi Mariusz,

I've been raving about my Omega Hemp Bipoles for a long time so I'm especially interested in your bipole prototypes. It almost seems counter intuitive as to how they can image so well with their opposing drivers whereas the deep sound stage is to be expected. Most of my friends that have heard my speakers are amazed that the little 4-1/2" drivers can project such a large sound stage and pull a disappearing act. Bass is fairly good too however I do run a sub. I imagine that a pair of the Rhymik OB subs would really create a magic synergy. aa

-Roy 

[Mariusz]

Hi Mariusz,

I've been raving about my Omega Hemp Bipoles for a long time so I'm especially interested in your bipole prototypes. It almost seems counter intuitive as to how they can image so well with their opposing drivers whereas the deep sound stage is to be expected. Most of my friends that have heard my speakers are amazed that the little 4-1/2" drivers can project such a large sound stage and pull a disappearing act. Bass is fairly good too however I do run a sub. I imagine that a pair of the Rhymik OB subs would really create a magic synergy. aa

-Roy

Hi Roy

Absolutely agree with you about the disappearing act of well design bipolar speakers.
In fact my original testing was done in mono (only one speaker) and it almost fouled me into believing that it was stereo reproduction. 
I had a chance to compare them to few speakers which are collecting dust and some which are my faves in my home. Those includes(ed) - AAD 2001 monitors (sold), Omega Super 8s monitors, my own double mouth horns and Martin Logans Aerius i. 
Without any exaggeration, they were on pare with some and better then most.

Their size (31.5"x10.25"x9.25") has some limitations ofcause and integrating two drivers as well as controlling the back wave is nothing to sneeze at but it can be done with fascinating results.
Just so you know, voicing my speakers is done by ear and frequency response is of absolute no interest to me. When it just sounds right that's when you need to leave your tweaker's ego behind either tho the little devil on your shoulder tells you otherwise.

The biggest challenge and effort was put in controlling the back-wave, cabinet (still working with different materials) and bass response. For cabinet of this size the bass is quite OK and pretty tight. (during the bass test some of my wall metal studs start rattling ......  )
In general, three characteristics in speaker design annoys me - boomy/unnatural bass, cabinet resonation due to poor construction and forward/HiFi-ish highs. 

If you aren't to far and would like to hear these we can  arrange it in a week or two when I will have them finished. Still waiting for my Bamboo veneer and then I am taking them on a short demo trip.

If they ever become available, I'll have them in two different driver choice. Both 8" full range drivers tho. Keeping them affordable will be my priority without sacrificing its performance (if ever).

Cheers
Mariusz

P.S

Almost forgot........
speaking of subs - if you like fast, tuneful bass, check these subwoofers out. They have few at special pricing as well.