MJAO G 098 - The Anagram - Crossover revision

nvrgdenuf · « **Reply #80 on:** 3 May 2009, 01:52 pm »

Scorpion,

If the fq response is as smooth as the plot shows, what a fantastic driver. I dont know squat above driver construction, but when I look at different driver fq plots, there seems to be some serious peak or dip someplace. I will think about ordering a pair and get back to you if I get them.
andy

Bonzite51 · « **Reply #81 on:** 7 May 2009, 01:46 pm »

The small story, you can't leave these changes out, then you will underperfom these good speakers. I hope you can see from the picture the chosen values. If not let's know. The Zobel is 3.9 ohm and 47 uF and the parallel notch 1mH and 10 uF.

/Erling

Hi, Erling,

just look at this simple parallel design:

8 Ohm (Alpha 15) parallel with 4 Ohm (Ciare CH250) and common Zobel= 4,2 Ohm+33 uF for both.

http://archive.http://www.audiocircle.com/index.php?action=gallerysearch&cat=0&pos=4

fergs1 · « **Reply #82 on:** 10 May 2009, 02:04 pm »

Greetings Erling, this project looks more inviting every day but I have a question, what sort of load would the mjao present to a valve amp esp a 300b se. Or would this be inviting dissapointment?
cheers fergs

Mr Content · « **Reply #83 on:** 10 May 2009, 02:14 pm »

Hey frergs, dont forget to drop by the Aussie forum

Mr C aa

Mr Content · « **Reply #84 on:** 10 May 2009, 09:57 pm »

Quote from: Mr Content on 10 May 2009, 02:14 pm

Hey frergs, dont forget to drop by the Aussie Circle

Mr C aa

scorpion · « **Reply #85 on:** 11 May 2009, 04:31 pm »

fergs,

I have been playing the MJAO with my Music Angel KT88 PP amp at 4 and 8 ohm output with no problems. Also in Gothenburg it played with one 6B4G SE 3 watt amp with great success. I think ouput transformer was specified to 8 ohm. However at the same meeting it played with another SE amp which I do not know the quality of but then the sound 'wobbled' if you know what I mean. I think it was a mismatch between output transformer and MJAO.

That's the tube story so far.

/Erling

BrassEar · « **Reply #86 on:** 11 May 2009, 06:12 pm »

Erling:

Care to help some of us with your passive XO for a SINGLE Alpha?

TIA

scorpion · « **Reply #87 on:** 11 May 2009, 07:43 pm »

Brassear,

I am a bit at loss hear, what to crossover about to, and why might I be of help ?
For what it is worth I think I will recommend MJK's effort to cross one Alpha15 with the Fostex 103E unit http://www.quarter-wave.com .
I have been doing research into this crossover and I think it will be doing just fine for the purpose designed. A single coil will let through to much in the 1 kHz - 2 kHz band.

/Erling

fergs1 · « **Reply #88 on:** 13 May 2009, 04:33 pm »

Greetings Erling, I wonder if I can just run this by you, could I substitute the monacor midrange with the scanspeak http://www.scan-speak.dk/datasheet/pdf/15m_4531k00.pdf . As luck might have it I can get a pair of these for the same price as the monacors locally, and I imagine the quality of the scanseak would be higher. The graph looks very similar but I'm a nuff nuff when it comes to the specs.Ive passed this project past the better half and so the excitement levels are growing

peace and goodwill fergs

scorpion · « **Reply #89 on:** 13 May 2009, 05:22 pm »

fergs,

A simulation with the ScanSpeak unit:

This should be fine. I have investigated 2nd order crossovers a bit more and would recommend 2nd order Linkwitz-Riley at around 250 hz which will take down the 2 kHz peak in the Alphas to a sufficient low level. 5 mH and 122 uF for the Alphas and 70 uF and 4.7 mH for the Revelator should be about right.
Let us here about the progress.

/Erling

fergs1 · « **Reply #90 on:** 13 May 2009, 06:42 pm »

Greetings Erling, thankyou kindly for your advice. I'm curious is the recommendation for 2nd order L-R just for the scanspeak/alphas combo or have you been investigating them for the original MJAO as well, and will this have an effect when using valve amps?
cheers fergs

scorpion · « **Reply #91 on:** 13 May 2009, 08:35 pm »

With the MJAO 2nd order filter for the Alphas took down the level a bit too much to match with the Monacors so I preferred to stay with 6 dB slopes. Here it seems the Alphas could be taken down some dBs to match with the ScanSpeaks. Also with regard to my trouble with the simple crossover for MJAO I was curious to measure the 2nd order filter and it will perform brilliantly without notch or Zobel which is a comfort.

/Erling

bratislav · « **Reply #92 on:** 22 May 2009, 04:13 am »

Hi Erling,

I don't know if it is just me, but I can't see any of you pictures you posted in this thread (including the final crossover). Could you please repost it ?

Thanks, Bratislav

scorpion · « **Reply #93 on:** 22 May 2009, 10:08 am »

The Gallery is not in place yet so pictures all over the Cicrle are missing at the moment. It will come back I suppose and the pictures with it. I reposted the new version of the crossover in post #72 from another source. I think the text will be enough to understand the rest of the design.

/Erling

nvrgdenuf · « **Reply #94 on:** 24 May 2009, 01:11 pm »

Selling the Monacors used by Scorpion in the For Sale section. Unused and at a big loss.

jkelly · « **Reply #95 on:** 20 Jun 2009, 04:35 am »

I and my friend John finally got around to converting my CS2 clones to the Anagram model.
We took the horns out and made a circular plate for the mid and tweeter.

I used your updated crossover but have some rheostats inserted to play with levels.
I am running the mids about 1/2 volume. (edit: Now replaced with Obbligatos - no pots)

The Monacor speakers are very smooth. I like them.
The tweeter however seems very directional. Together they do
a great job.

I am playing with postioniing to lessen and tighten the bass.
I am starting to think I may want to try different bass drivers. I actually
like the sound of bass from the 18" Goldwood better than the 2 Eminence.
Any suggestions on a new pair of 15" 's ?

I only have about 40 hours on the mid and tweet and hope they
continue to improve and add more magic as they break-in.

On some songs the system is excellent. I am having better luck
with these than the CS2 clones.

Jeff

ttan98 · « **Reply #96 on:** 20 Jun 2009, 12:06 pm »

I made CS2 clone as well, you see I add in a midrange like you and found the overall sound improves. Even better Emerald Physics found that too because CS2.3 now includes a midrange as well.

Cheers enjoy your speaker.

BTW you may like to consider Hawthorn 15" woofer as a replacement, if you do use 2 units per side instead of just 1 unit.

Telstar · « **Reply #97 on:** 20 Jun 2009, 03:32 pm »

Quote from: jkelly

I am playing with postioniing to lessen and tighten the bass.
I am starting to think I may want to try different bass drivers. I actually
like the sound of bass from the 18" Goldwood better than the 2 Eminence.
Any suggestions on a new pair of 15" 's ?

Beyma.

Piek · « **Reply #98 on:** 23 Jun 2009, 10:32 am »

Quote from: jkelly on 20 Jun 2009, 04:35 am

The tweeter however seems very directional.

Maybe because the distance of tweeter and mid is too large (for my taste).

Regards, Micha

scorpion · « **Reply #99 on:** 23 Jun 2009, 05:22 pm »

Very nice built Jeff !

I do think that also the midrange will improve a bit when played in.
I usually sit in the sweetspot when listening but you are in fact right about the tweeter beaming. That is a function of the 'waveguide' build. In fact the effect is less pronounced if the DT-28 is placed on the baffle surface rather than sunked in. A bit contrary to what one would think. But all in all it is a very good tweeter for the price and delivering nice non-fatigueing sounds. I would agree with Micha that placing the tweeter more close to the midrange would allow for a bit better blending perhaps.

/Erling