Simple Passive Harsch XO Using PTT6.5 and RS28F in a Waveguide

[xrk971]

I have to start with something cheaper than those.

Would a $37 RST28F fit the bill? Fitted to a WG300 for $16 seems like a very cost conscious yet good sounding combo.

Here was the RS28F and RST28F compared in a WG300:

Hmm... Might just have to look into waveguides for the t34a I've got here first.

You may need to design a custom WG and get it 3d printed - unless the size of the mesh basket on the Bliesema T34A is standard diameter. The WG300 for example is 40mm dia throat.

 

[mainframe99]

I would guess the jantzen waveguide made for the TW034 tweeter (which funnily enough I also have a pair of in my JBL SVA2100's) can fit the T34A, but no way I'm paying that price to find out. 3D printing looks like my only option

 

[xrk971]

The Jantzen WG for TW034 tweeter is 48 euro each - seems reasonable price if it fits. You will spend at least 15 Euro to print one, after you design it. The Jantzen one is machined hard plastic vs 3d printed so might sound better.

What is the diameter of the T34A mesh basket?

 

[mainframe99]

Its massive it would be about 80mm but I think it can be removed, not easily

 

[ErnieM]

The grill comes off pretty easily. Nice flush surface to work with.

Would be very impressive with a waveguide....

 

[PKAudio]

My WG for T34B has throat diameter 39.2 and it is perfect fit, up to 40mm it would still be ok. Jantzen WG has throat diameter 44mm.

 

[dwk123]

WG300

Is there a North American source for these? None of the usual suspects seems to offer them.

 

[mainframe99]

Hmm maybe WG300 could work for the T34A. Will take a measurement tonight

 

[xrk971]

WG300 is 40mm throat so seems perfect for T34A. I guess the grill is much bigger than the dome.

 

[xrk971]

I was lucky enough to have a friend in EU give them to me as a gift. They were designed for the DT300 tweeter which might be pretty good. You could save yourself the trouble of making an adapter if it fits. Priced well at 50Euro too.

MONACOR: DT-300

 

[Solve]

Would a $37 RST28F fit the bill? Fitted to a WG300 for $16 seems like a very cost conscious yet good sounding combo.

Looks like an good combo think I buy those.
Already have the Purifi ordered.

 

[Solve]

Is there any BOM for the harsch crossover?
Or have I missed it?

 

[xrk971]

Passive Harsch XO BOM

Parts Express part numbers

For L1:
1x Dayton Audio CF16-68 0.68mH 16 AWG Copper Foil 257-624 - if you can’t find this as it was a blow out sale - alternate is:
1x Jantzen 1854 0.68mH 15 AWG Air Core Inductor 255-414

For R4:
1x Jantzen 4.70 Ohm 10 Watt Audio-Grade Superes 255-949

For R2:
1x Jantzen 2.20 Ohm 10 Watt Audio-Grade Superes 255-946

For L2:
1x Jantzen 0.33mH 18 AWG Air Core Inductor 255-220

For C2:
1x Jantzen 3.3uF 400V Z-Standard Capacitor 027-270

For R1:
1x Dayton Audio DNR-7.0 7 Ohm 10W Precision Audio Grade R 004-7

For R5:
1x Mills 47 Ohm 12W Non-Inductive Resistor 005-47

For C1:
2x Dayton Audio PMPC-4.7 4.7uF 250V Precision Audio Capacitor 027-230

1x Passive XO PCB for Transient Perfect FAST speaker, adapted to this XO.

6x 0.250 Faston tab PCB connectors (get from anywhere)

Approximate schematic:

Fully assembled crossover:

The PCBs are available here:
Transient Perfect Crossover PCB for 10F/RS225 FAST Speaker | Etsy

 

[Solve]

Passive Harsch XO BOM

Thanks it's tempting to have it integrated and don't mess with miniDSP
even if its quite a lot of money.

I listen to Purifi now in some small boxes I had and it is realy something special.
Just waiting for your TL build to see what you think about it.

 

[xrk971]

You could save some money using all Dayton Audio brand parts - they sound great actually. My prototype XO used all Dayton and measured about the same. Only 8 parts and no really expensive parts. Probably $40 to $50/pair in parts not including PCB and you can P2P it. That’s quite inexpensive for a passive XO. Especially one that can do the whole transient perfect thing.

 

[454Casull]

Wago blocks!!! My favourite thing.

 

[Solve]

You could save some money using all Dayton Audio brand parts - they sound great actually. My prototype XO used all Dayton and measured about the same. Only 8 parts and no really expensive parts. Probably $40 to $50/pair in parts not including PCB and you can P2P it. That’s quite inexpensive for a passive XO. Especially one that can do the whole transient perfect thing.

I put my Prurifi in some old Argon 7220 that I have as tv speakers.
Just stole it and put som small kitchen speakers there and wonder if my wife should recognice it.
No.

Anyway I did I dust of my RPI with Volumio and did an dirty measurement in REW to use it with there DRC.

WTF!
How good could it sound!?
DRC think I would 40hz in those small boxes, in bruel and kjaer listening curve.
I could live with this.
But.
Need ASIO to Cubase and same reference global listening.
So an speaker, desktop as I hope your TL could loose the problem even if I know it's not an perfekt system maybe it's work.
MiniDSP, I dont know, sold mine, have Khadas Tone Board amazing,yes budget stuff as an DIY and now Purifi...

 

[xrk971]

I have used active XO’s a lot with miniDSP and other DSP’s. But I still think a well done passive XO still beats the active solutions in ultimate sound quality. Plus, it lets you try out different amps to see how they sound (if you make as many amps as I do).

 

[xrk971]

Revised Plans for TL with Corrected Baffle Cutouts

Updated drawings for the TL with a removable baffle. I re-measured the driver cutout diamters, depths and CTC spacing. The previous drawing is incorrect for the baffle cutouts, please use these drawings. Drawings are available in PDF and JPG below.

 

[Ugg10]

Thanks @XRK971 for all the hard work, much appreciated by me and many others.

I have been having a play with the Leonard TL calculator and would appreciate opinions on the mini tower and tall&skinny tower TLs that I have (very badly) sketched up and modeled. Both attempt to keep the same line length as XRK's (calculated at 88.75", correct ?) but in different form factors. I prefer the tall&skinny but thought welcome. The models come out pretty similar (I think the T&S has slightly better response but this is in the rounding of the measurements so not significant).