Decware // Reference ZMF OTL

[goldwerger]

Hi everyone!

This thread is intended to be dedicated to the Decware // Reference ZMF OTL tube amplifier, the result of a collaboration between ZMF and Decware, two leading bouqitue brands of headphones and amplifers, respectively (both hailing from Illinois).

Since posting my review of this amplifier earlier this year, I've received several private messages with questions from current and prospective owners. I thought it may be a good idea to have a public thread, so knowledge can be captured and widely shared.

This is your space for anything related to this wonderful amp: from tube rolling, headphones, and chain synergies... to tips, troubleshooting, and advice.

Resources:

• ZMF product page: https://www.zmfheadphones.com/decware-amp
• Head-Fi product page: https://www.head-fi.org/showcase/decware-zmf-reference-otl.26421/

ZMF YouTube video:



My review:

https://www.head-fi.org/showcase/decware-zmf-reference-otl.26421/reviews#review-30541

 

[busseysound]

Thanks for setting it up! If time permits this week I'll be posting my journey with it over the last 2 months with tube rolling, etc. I have been blown away by this amp in combination with my VC's.

 

[goldwerger]

Thanks for setting it up! If time permits this week I'll be posting my journey with it over the last 2 months with tube rolling, etc. I have been blown away by this amp in combination with my VC's.

Excellent. Looking forward to reading about it here!!

My current tube roll is a little unique, using Tung-Sol 5687 for output tubes (with adapters). I loved the 6N6P, which (other than being more readily available and much cheaper) is very smooth and relaxed, but the 5687 (mine are dated 1957) tubes offer a bit of extra transparency that is so great. Note that some adapters won't fit and will need to be mounted on top of tube extenders (a bit of buildling two little stacked twoers), but I did find adapters that fit, so it can be done very easily. For input tube, I'm currently using RCA 6BQ7A (black plates o getter 1957). I'll be rolling in a PCC189 soon and try that. For rectifier, I'm using the always reliable GZ34 (Philips Miniwatt brown base DD getter).

Most of my listening on this amp is with the AC and AO, as well as the ADX5000 (really good synergy with all).

I also love this as a preamp into the Decware Taboo (I have an older SE84TS+ model). On this combo, the Caldera is as good as I've ever heard it. Same for the Susvara (with a powerful gain tube on the Taboo).

 

[OctavianH]

What's the price of this amp? I cannot find any info about it.

 

[goldwerger]

What's the price of this amp? I cannot find any info about it.

Here is the product sale listing on ZMF's website:

https://shop.zmfheadphones.com/collections/amps-dacs/products/decware-zmf-otl

Price is $4,200

If you already bought a ZMF headphone or going to get one, there is a bundle price which, I believe, is a few hundred dollars cheaper (not sure exact figure, you can reach out to @zach915m for the specifics)

 

[cats4cans]

Is there a summary of the differences versus the CSP3? Or is only loosely based on it because they’re both Decware OTL. Looks like some seriously bigger caps, different power tubes, and I’m assuming a fully tricked out power supply. The ZMF/OTL would be a stretch for me (especially because I keep buying other things), but a near stock CSP3 is doable. Maybe get the signal cap upgrade OR the anniversary mods, but not both. Probably a very small pool of people that have sufficient exposure to both. I wonder if Steve Deckert has already given a detailed answer on this that I just need to find.

 

[goldwerger]

Is there a summary of the differences versus the CSP3? Or is only loosely based on it because they’re both Decware OTL. Looks like some seriously bigger caps, different power tubes, and I’m assuming a fully tricked out power supply. The ZMF/OTL would be a stretch for me (especially because I keep buying other things), but a near stock CSP3 is doable. Maybe get the signal cap upgrade OR the anniversary mods, but not both. Probably a very small pool of people that have sufficient exposure to both. I wonder if Steve Deckert has already given a detailed answer on this that I just need to find.

No formal spec sheet comparing the two (doubt one will be produces exactly as such), but check out Zach's video.. go to min 2:42 where he discusses some of the differences in the caps while showing the inside components. He also mensions the fact components are upgraded throughout at min 7:21:



I'm sure they are similar DNA but I've never tested these two side-by-side. A practical limitation of making such a subjective comparison would be that the CSP3 has a ~2 year waitlist (or wherever Decware waitlist is at now) and the ZMF OTL is immediately available.

 

[zach915m]

Is there a summary of the differences versus the CSP3?

Steve didn't want the CSP to be compared because he feels they are so different, but ofcourse with the form factor it's an obvious comparison.

After looking at them side by side they share a simular bare bones but none of the parts are the same, and they utilize the tubes differently through those parts. I think the video definitely does the best job as @goldwerger vs anything I can add.

 

[G8torbyte]

I'm sure they are similar DNA but I've never tested these two side-by-side. A practical limitation of making such a subjective comparison would be that the CSP3 has a ~2 year waitlist (or wherever Decware waitlist is at now) and the ZMF OTL is immediately available.

@cats4cans I just checked my CSP3 order on their Build Sheet. My order went in Apr 2022 and they are working through QC'ing the Sep-Nov 2021 orders. So yeah, still looking like a two-year wait time. It's OK with me as I knew going in it would take some time.

 

[goldwerger]

@cats4cans I just checked my CSP3 order on their Build Sheet. My order went in Apr 2022 and they are working through QC'ing the Sep-Nov 2021 orders. So yeah, still looking like a two-year wait time. It's OK with me as I knew going in it would take some time.

When you get it, would be great to compare notes..

 

[G8torbyte]

When you get it, would be great to compare notes..

Sure, will do. I recently acquired the Icon Audio HP8-Mk2 and enjoying it with the ZMFs. It is at an equivalent price with the CSP3 so it will be interesting to compare each on the performance/characteristics with the CSP3's OTL configuration to the Icon's custom wound multi-tap output transformer.

 

[goldwerger]

Sure, will do. I recently acquired the Icon Audio HP8-Mk2 and enjoying it with the ZMFs. It is at an equivalent price with the CSP3 so it will be interesting to compare each on the performance/characteristics with the CSP3's OTL configuration to the Icon's custom wound multi-tap output transformer.

Great to know!

My end, after 8 months of more or less continuous use, I still haven’t found any amp that sounds as good as the Decware/ZMF OTL with high impedance headphones (including the GOTL). It’s really a gift that keeps on giving..

 

[G8torbyte]

@goldwerger Yeah, I can imagine the how nice it is. I spoke with Zach back at the last NYC CanJam about how the Atrium Open and the ADS damping was a game-changer for me. I jumped on the AO during the first releases in 2022. Early in 2022 I looked into Decware and ordered the CSP3 as a good OTL to pair with it after reading many comments how ZMFs perform with OTL amps. Then just a few days after my CSP3 order, Zach announced the ZMF/Decware collaboration. I told Zach how awesome it sounded with him and Steve working together. I may have gone that direction on their collaboration if I had not already committed but I was also trying to stay at a lower price-point. They are two hard working audio companies with a passion and I'm glad to support them with my enthusiasm for music and audio equipment.

 

[goldwerger]

@goldwerger Yeah, I can imagine the how nice it is. I spoke with Zach back at the last NYC CanJam about how the Atrium Open and the ADS damping was a game-changer for me. I jumped on the AO during the first releases in 2022. Early in 2022 I looked into Decware and ordered the CSP3 as a good OTL to pair with it after reading many comments how ZMFs perform with OTL amps. Then just a few days after my CSP3 order, Zach announced the ZMF/Decware collaboration. I told Zach how awesome it sounded with him and Steve working together. I may have gone that direction on their collaboration if I had not already committed but I was also trying to stay at a lower price-point. They are two hard working audio companies with a passion and I'm glad to support them with my enthusiasm for music and audio equipment.

Same as you, Got my AO when it released at CanJam Chicago 2022.. and yea, these are two great brands and privately owned brands that made so much sense to try and put this together. I’m sure you’d love your CSP3!

 

[G8torbyte]

Same as you, Got my AO when it released at CanJam Chicago 2022.. and yea, these are two great brands and privately owned brands that made so much sense to try and put this together. I’m sure you’d love your CSP3!

Thanks, I'm looking forward to the CSP3 arriving maybe in the Spring 2024. So my plan later is to do a three-way shoot-out/comparison of the Decware CSP3, the Icon HP8-Mk2 and a RAAL-Requisite PDT-1a OTL Amp. I'll write it up for sharing the impressions and coordinate it with Head-Fi admin how best to post. Each of these are around the $1500-$2K range which seems like a price-point of interest to many entering the tube-amp journey. I did run into an issue with the RAAL-requisite already. It was performing very well for several months until one of the output channels started over-heating and red-plating the driver tube. I can't figure what is causing that and I'll need to work with a local shop in my area. Anyway it'll be fun once all three are ready to compare.