Shamrock SE-2 Schematic

Bill Fitzpatrick · 6th April 2005, 06:38 PM

I just got the drivers and plans for a Shamrock SE-2 from a member of the forum.

The crossover diagram seems odd though. It's got a series RCL shown across the amp terminals. The values are 8ohm, .25mh and 35mfd. Resonance calculates to 1700Hz. Weird.

If anyone has a schematic for this I would be greatful for a copy. A verbal description would serve as well.

Alternatively, a crossover design for a MTM using Vifa P17WJ008 and D27TG45 would be nice.

Thanks

Davey · 6th April 2005, 08:11 PM

It's not weird, it's an excellent design.
The RCL network is a conjugate which "reverses" the reactive nature of the crossover network and makes the load look more resistive. Beneficial for tube amplifiers mainly. With a good solid-state amplifier the system should fine with or without it.

The SE-2 IS an MTM design for P17WJ008 and D27TG45. You're looking for alternatives?

Cheers,

Davey.

Bill Fitzpatrick · 6th April 2005, 11:59 PM

Quote:

Originally posted by Davey
It's not weird, it's an excellent design.
The RCL network is a conjugate which "reverses" the reactive nature of the crossover network and makes the load look more resistive. Beneficial for tube amplifiers mainly. With a good solid-state amplifier the system should fine with or without it.

The SE-2 IS an MTM design for P17WJ008 and D27TG45. You're looking for alternatives?

OK. I was just surprised to see it.

I'll try Shamrocks crossover design first unless you know of a better one for these drivers.

Thanks

Dick West · 7th April 2005, 12:05 AM

Some web research indicates that the designer of the crossover in question was affiliated with Lynn Olson, a heavy tube user. Mike McCall of Shamrock was in Silverton and Lynn in Portland, Oregon. So, the xover design makes a lot of sense when one considers the tube interest mid 90s when the SE-2 was developed.

Raoul · 7th April 2005, 02:12 AM

Hi Bill,

Funny, I just got back from Eugene. Good to see you weren't riding your motorcycle around MLK last night (reference to your old avatar). I would be interested to hear about your impressions of the Shamrock loudspeaker when you finish building it, although it looks like Shamrock doesn't sell the plans anymore. What is the sensitivity of the SE-2?

Bill Fitzpatrick · 7th April 2005, 04:36 AM

Quote:

Originally posted by Raoul
Funny, I just got back from Eugene. Good to see you weren't riding your motorcycle around MLK last night (reference to your old avatar). I would be interested to hear about your impressions of the Shamrock loudspeaker when you finish building it, although it looks like Shamrock doesn't sell the plans anymore. What is the sensitivity of the SE-2?

Yeah, I read about that. Major bummer. Sometimes I think I should quit riding. Some wingnut ran a red yesterday and almost took me out.

Well, the mid/woofs are 88db and they're wired in parallel. But then considering BSC, if there is any, we're
back to 88.

Frankly, I haven't been able to find what I really want in a satellite unit so I'm just poking around with the lesser choices.

r!sc! · 7th April 2005, 12:12 PM

I have plans for SE-1 and SE-2. BUT, I don't have nice words for SE-1. I've been realy disapointed in crossover and box plans. Then I change the crossover, make some arangement in the box and SE-1 now realy sings...

Maybe is SE-2 better, i don't know... Drop me email for plans.

Boban

Samuel Jayaraj · 7th April 2005, 01:57 PM

Early KEF speakers used conjugate load matching; they make almost any amp perform optimally. I wonder why this is not used more often??!!

Davey · 7th April 2005, 02:34 PM

Bill,

I would try the SE-2 schematic as-is. Admittedly, this set of drivers is rather mediocre and boring relative to the current drivers preferred by the DIY crowd, but the performance is quite good considering the price...IMHO.

Also of note regarding both the SE-1 and SE-2 is that the design of the D27TG45 tweeter changed slightly after the initial crossover design by Mike. However, I'm not sure how much relative difference this made since my speakers used the earlier tweeter and measured excellent.

Cheers,

Davey.

Bill Fitzpatrick · 7th April 2005, 04:09 PM

Quote:

Originally posted by r!sc!

Maybe is SE-2 better, i don't know... Drop me email for plans.

I have plans and seemingly the correct crossover. Thanks.

Quote:

Originally posted by Davey
Admittedly, this set of drivers is rather mediocre and boring

What do you mean by boring?

6th April 2005, 06:38 PM	#1
Bill Fitzpatrick diyAudio Member Join Date: Jun 2001 Location: Eugene, OR	Shamrock SE-2 Schematic I just got the drivers and plans for a Shamrock SE-2 from a member of the forum. The crossover diagram seems odd though. It's got a series RCL shown across the amp terminals. The values are 8ohm, .25mh and 35mfd. Resonance calculates to 1700Hz. Weird. If anyone has a schematic for this I would be greatful for a copy. A verbal description would serve as well. Alternatively, a crossover design for a MTM using Vifa P17WJ008 and D27TG45 would be nice. Thanks

7th April 2005, 01:57 PM	#8
Samuel Jayaraj diyAudio Member Join Date: May 2001 Location: Bangalore, India	Early KEF speakers used conjugate load matching; they make almost any amp perform optimally. I wonder why this is not used more often??!! __________________ Sam

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6th April 2005, 08:11 PM	#2
Davey diyAudio Member Join Date: Dec 2001 Location: Bremerton, WA.	It's not weird, it's an excellent design. The RCL network is a conjugate which "reverses" the reactive nature of the crossover network and makes the load look more resistive. Beneficial for tube amplifiers mainly. With a good solid-state amplifier the system should fine with or without it. The SE-2 IS an MTM design for P17WJ008 and D27TG45. You're looking for alternatives? Cheers, Davey.

7th April 2005, 12:05 AM	#4
Dick West diyAudio Member Join Date: Aug 2004 Location: Illinois	Some web research indicates that the designer of the crossover in question was affiliated with Lynn Olson, a heavy tube user. Mike McCall of Shamrock was in Silverton and Lynn in Portland, Oregon. So, the xover design makes a lot of sense when one considers the tube interest mid 90s when the SE-2 was developed.

7th April 2005, 02:12 AM	#5
Raoul diyAudio Member Join Date: Feb 2003 Location: OR	Hi Bill, Funny, I just got back from Eugene. Good to see you weren't riding your motorcycle around MLK last night (reference to your old avatar). I would be interested to hear about your impressions of the Shamrock loudspeaker when you finish building it, although it looks like Shamrock doesn't sell the plans anymore. What is the sensitivity of the SE-2?

7th April 2005, 12:12 PM	#7
r!sc! Account Disabled Join Date: Jun 2003 Location: Serbia	I have plans for SE-1 and SE-2. BUT, I don't have nice words for SE-1. I've been realy disapointed in crossover and box plans. Then I change the crossover, make some arangement in the box and SE-1 now realy sings... Maybe is SE-2 better, i don't know... Drop me email for plans. Boban

7th April 2005, 02:34 PM	#9
Davey diyAudio Member Join Date: Dec 2001 Location: Bremerton, WA.	Bill, I would try the SE-2 schematic as-is. Admittedly, this set of drivers is rather mediocre and boring relative to the current drivers preferred by the DIY crowd, but the performance is quite good considering the price...IMHO. Also of note regarding both the SE-1 and SE-2 is that the design of the D27TG45 tweeter changed slightly after the initial crossover design by Mike. However, I'm not sure how much relative difference this made since my speakers used the earlier tweeter and measured excellent. Cheers, Davey.

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