Anyone using the Takman Rex CF resistors? Report?

[67Mopar]

I decided to go back to stock value metal film capacitors in my RK100. Instead of using China made Xicon brand, I chose Japan made Takman REY metal film resistors.

[IMG750]http://i1250.photobucket.com/albums/hh536/soldanofan/DSCN3256_zpsfc939941.jpg[/img]
[IMG750]http://i1250.photobucket.com/albums/hh536/soldanofan/DSCN3277_zpsef603343.jpg[/img]

[xtian]

Cool photos and info, 'par. I'm not familiar with Cornford. What circuit is this?

[67Mopar]

The circuit is Marshall inspired. 4 x gain stages, cathode follower, tube buffered loop, PI of-course. Tone-stack is positioned post CF, and the MV is positioned pre PI. The headroom available is astounding! Checkout the size of the transformers...

[IMG750]http://i1250.photobucket.com/albums/hh536/soldanofan/DSCN2703_zps47a7117c.jpg[/img]

I embarked on a quest to discover why Cornford amplifiers exhibit such a singularly unique character? After 3 resistor type changes, capacitor changes, and varied modifications, the amp always maintained its core personality. The greatest audible change came via the filtering. Altering component values and construction types is like changing the backup singers in a band... It's a matter of how the lesser parts "harmonize" with the greater parts.

My summation: The most prolific "tone generators" in any amplifier are the transformers.

[67Mopar]

Edited double post.

[rooster]

Wow, good review, Mopar67. Having recently changed an OT in my AC30TB build to a MM product, I agree the transformers are a big influence on the final sonic results. But I would not discount the speakers - and the cabinet they reside in - over the transformers. I am not sure I have enough variety of speakers and cabs to present the challenge, but my thought is a mediocre amp can be made to sound noticeably better with a speaker/cab swap than it can with a PT/OT swap. Well, provided they (the trannys) are not total shite to start with, eh?

Well, it all makes a difference in the end if you have ears to hear. I do think it interesting that in the Cornford you can hear the consistency of the trannys throughout the part swaps. That does speak highly of them. So who makes the trannys anyway? Do you know?

I also will add that you might be the only person I know of who would be part swapping in a $2500 amp.... Ha, but I'm glad you did and I'm glad you shared it with me. Thanks.

[67Mopar]

Wow, good review, Mopar67. Having recently changed an OT in my AC30TB build to a MM product, I agree the transformers are a big influence on the final sonic results. But I would not discount the speakers - and the cabinet they reside in - over the transformers. I am not sure I have enough variety of speakers and cabs to present the challenge, but my thought is a mediocre amp can be made to sound noticeably better with a speaker/cab swap than it can with a PT/OT swap. Well, provided they (the trannys) are not total shite to start with, eh?

Well, it all makes a difference in the end if you have ears to hear. I do think it interesting that in the Cornford you can hear the consistency of the trannys throughout the part swaps. That does speak highly of them. So who makes the trannys anyway? Do you know?

I also will add that you might be the only person I know of who would be part swapping in a $2500 amp.... Ha, but I'm glad you did and I'm glad you shared it with me. Thanks.

I agree totally on the speaker/cabinet choice. Cornford favors pine cabinets, which wouldn't be my first choice. Pine resonates too freely to my ears. I find small pine combo cabinets to be beneficial, but going too large tends to 'blur' the notes. Now if I plug my AC30 head into the pine Cornford 2x12, it's the bomb-diggity!

$2500.00 - shwuny five hundred! I've been working with electrical circuits since I was 17 years old - 51 now. If you know what you're doing, it's completely benign. I started the project to rid the amp of the RoHS "cold-joint" solder, and progressed from there.

Now, when I see amplifiers that have been drilled, gutted, gooped...

[IMG:399:300]http://i1250.photobucket.com/albums/hh536/soldanofan/Screenshot2014-03-28at50913PM_zps80446231.png[/img]

I mean... WTF? I believe this WAS a Marshall?

[deniz]

67Mopar, this is an excellent piece of information. Personally I was never in favour of Xicon because if just felt cheap to be honest. The output of the amp was not as great as it should have been and since I have these capacitors in my circuit currently, I have been trying to find a reason and motivation to replace them. This thread just gave me motivation and a great replacement for them as well.

printed circuit board assembly

[Mark]

I'll have no basis for comparison, but I decided to try the Takman's. I liked the amp to begin with and I'm not too familiar with the Rocket. So it was more about using parts with a lot of QC.

[img766]http://i149.photobucket.com/albums/s69/ ... eaefd0.jpg[/img]

The build turned out nicely, how much the Takman's contributed to that I don't know.

[67Mopar]

I'll have no basis for comparison, but I decided to try the Takman's. I liked the amp to begin with and I'm not too familiar with the Rocket. So it was more about using parts with a lot of QC.

[img766]http://i149.photobucket.com/albums/s69/ ... eaefd0.jpg[/img]

The build turned out nicely, how much the Takman's contributed to that I don't know.

Nice!

I tried the REX carbon-films in the RK, but ended-up refitting the amp with the REY metal-films. The CF's seems to exhibit a sort-of "looseness" that I didn't care for in the RK100. I though they would be noisier by a small margin, but that wasn't the case.

If I were building a NMV amp, I don't think I'd have an issue with the REX resistors. In the end, I strived for stock sound with HQ components.

[67Mopar]

67Mopar, this is an excellent piece of information. Personally I was never in favour of Xicon because if just felt cheap to be honest. The output of the amp was not as great as it should have been and since I have these capacitors in my circuit currently, I have been trying to find a reason and motivation to replace them. This thread just gave me motivation and a great replacement for them as well.

printed circuit board assembly

I never would have replaced the resistors, had the amp been operating quietly. There were a lot of clicks, pops, and a light amount of hissing.

As far as "tone" is concerned... I don't hear a difference between the Xicon MF and Takman MF. I could claim them as being quieter, but I don't think that would be accurate. The clicks, pops, hiss, etc., was more likely due to cold solder joint(s) and failed signal capacitors. I prefer the Takman's for their larger diameter leads. The stout leads are great for arching them over fasteners and, cooler operation.

[hbamp]

They are good open sounding resistors. I like them in any amp. So I like kiwames to. More lifely as metal films. The kiwames are more vintage sounding resistors. Hard to discribe exactly they are warmer and seem to have some kind of natural crisp tone like the cc Allen Bradleys. Better responding amp.

[David Root]

I've used them in some builds for several years now. The 1/2W are a tad small but they have no problems on high voltage duty like plates, unlike those much smaller "made in India" 1/2W, which are crap.

IIRC they are also totally non-magnetic FWIW.

I've no doubt they are better in the signal path than Xicons, but I wouldn't necessarily use them everywhere, at $0.75 each.

And yes I like the Kiwame 2W as well, but they are even more expensive.