Upgrading Klark Teknik Gear

[gaugedgc]

I have a kt-76 and a kt-2a and im looking to upgrade both units, ive heard about replacing the tubes but im unsure as to which tubes i should get, i have already upgraded the opto cell in thr kt2a to a kenetek, just looking for some advice on upgrading the tubes and or anything else that can be done to the units, thanks

[Aled Hughes]

The 76 doesn’t have tubes.

What is it you don’t like about them?

[gaugedgc]

The 76 doesn’t have tubes.

What is it you don’t like about them?

Nothing that I dislike, just wanted to improve them if there where any ways too without spending a whole lot, do you know of any good tubes for the kt-2a?

[CS70]

What Aled says. How do you know there's something to improve?

Do you like the sound? Keep it. You don't like it? What is that you don't like about it? Maybe it ain't anything to do with the tubes.

But of course if you want a couple of NOS tubes compatible with the 2A at $1000 a piece, I happen to have some. They will make your mixes sound amazing!

[Martin Walker]

Hi gaugedgc, and welcome to the SOS Forums!

I personally find gear upgrades a fascinating topic, and although I have to echo the other replies here, I suspect I can guess your motivation - you have some good gear, and would like to sound even better, which after all ought to be a lot cheaper and less disruptive than buying more upmarket gear and then selling what you have. I'm sure we all have thoughts like those from time to time.

It's even more intriguing once you've noticed various companies offering to 'upgrade' gear items with quieter and audibly better op-amps, NOS tubes, cleaner-sounding capacitors, and so on, offering to turn a mid-range product into one with boutique pretensions - at a price. There's a place for all of these treatments in the grand scheme of things, but I can't help personally thinking that:

a) Such tweaks must be subject to the law of diminishing returns, and it's difficult to know when to stop, or even whether it's worth starting at all.

b) Unless you have a fair amount of previous personal experience, it's easy to get sucked into a spiral of possible improvements or possible disappointments, which could be rephrased as 'a little knowledge is a dangerous thing'.

If you're prepared to devote a fair bit of time (and at least some money) to the proceedings then gear upgrading can be a great DIY undertaking - you'll either learn a lot along the way and improve your sound, or you'll end up disillusioned and maybe feel out of pocket. If you approach specialist engineers to do the upgrades for you it will cost more but you'll benefit from all their research and possibly get more audible improvements.

However, no-one should underestimate the time or money involved in either approach - in my experience anyway there are rarely any really cheap & easy ways to significantly improve the performance that the original manufacturer decided on.

I'd be delighted to be proved wrong though!

Martin

[James Perrett]

Am I right in thinking that these use transformers in the signal path? I suspect that is where the compromises have been made to bring the price down. You'll probably hear the biggest change by changing the input and output transformers. If you want really top quality sound then you need to replace the transformers by active drivers and receivers. However, that will compromise the originality of the units and probably misses the point of owning the units entirely. These units are desirable because of the flaws in their sound - so you need to have a good think about what you like and what you don't like about them.

[ef37a]

I can only echo what Martin has said (sort of) "If it ain't broke?)

The three valves in question are,...
12AX7 (ECC83) and these last decades, even in bish-bashed guitar amps.
12BH7 A higher power double triode that can deliver 5 clean watts and stand 2kV! Very unlikely to fail in a compressor. But, quite rarely seen in gear, There is (was?) the monster SVT which uses them and a Blackstar amp, little else AFAIK so getting in a spare or two might be wise?

Like the 83, the EL84 will be around for ever but probably get more expensive as will all valves IMO.

"Improvements? Well if you take noise, most of that is caused by the resistors in any audio circuit be it valves or op amps and you cannot frigg about with those because the values are set in stone for the correct operation of the valve. A good replacement for the 12AX7 is the TAD 7025 HG. Low microphony and a fair price.

Distortion: Yes, that can vary between valve samples but at 'line' levels is likely much lower than that caused by the compression circuits. I note from the specification that the compressor has an input resistance of 600 Ohms? If so, that could cause distortion in whatever drives it. Op amps such as the NE5532 will drive 600R with low distortion but a TL072 will not be at all happy!

Any equipment modification, (other than a valve swap. For the EXACT same type!) will require a service manual and some test gear such as a good AC mV meter, distortion analyser and a low distortion audio signal generator. An oscilloscope is also almost indispensable.

Dave.

[knave101]

I have upgraded both the KT EQP-KT (Pultec copy) and the 76-KT.

My upgrades were capacitor upgrades, both film and electrolytic. All of the components were basically cheap.

I upgraded all electrolytics to Audio grade electrolytics, and film caps to Polypropylene or polystyrene. I did not replace the higher voltage electrolytics. I also replaced the tubes on the EQP with vintage.

I did not replace the Midas transformers.

Does it make a difference? In reality, I did the upgrade immediately after purchase. In my opinion, upgrading capacitors to polypropylene or polystyrene is a well known "immediate" upgrade. Such an upgrade withstands the perils of mix down, and clarity that only seems to really be noticeable when competing with other tracks in the mix for 'audio space'....then the reward becomes more apparent.

These caps don't cost a fortune. replacing the lower voltage electrolytics with audio grade Nichicon or Elma is also not to difficult. But audio caps can be double or triple size of their budget equivalents...so space is of concern. One has to measure the space on the board, the pin spacing. The circuit boards on the KT are not so easy to solder/unsolder imo. Both my units work well now and sound great. I think its particularly important upgrade for the EQP....as EQ is usually dramatically improved with capacitor upgrade.

I keep a list of all the caps, spacing, voltages etc....for anyone who is interested.

[forumuser840717]

I've obviously not been paying attention but when did KT start making ripoffs of other company's old kit?

[Wonks]

I've obviously not been paying attention but when did KT start making ripoffs of other company's old kit?

They are now part of Music Tribe/Behringer (since 2009). So they do what Uli says.

[Hugh Robjohns]

I've obviously not been paying attention but when did KT start making ripoffs of other company's old kit?

Since they were assimilated into the Uli Collective!

[Hugh Robjohns]

I have upgraded both the KT EQP-KT (Pultec copy) and the 76-KT.

If you like what you've done then that's fine. I don't want to say what people should or shouldn't do with their property.

But I do struggle with the concept of knowingly buying something cheap and therefore of inherently limited quality, and then spending a lot of time, money and effort turning it into a cheap unit with some expensive capacitors in it.

[knave101]

Your point is well taken. But as many of us have a problem...being gear heads, we love fixing stuff! As an engineer myself, I am always fixing a project of sorts. Parts cost of retail units is typically about 1/3 retail cost. So I specifically buy cheap stuff that's designed well, where the cost cutting is in the transformers, capacitors...as these are where the cost is. The Peavey VMP2 and VCL2 are a classic case in point. Great design, cheap parts. However, it's not an issue, because I work 'for free' on my own gear.

Another Case in point: I have an A-Designs Pacifica preamp. This is a fantastic Quad Eight adaptation. Cost is over 2k new. Yet, the electrolytics inside are ALL still the cheaper variety. Even the critical bipolar is Nichicon, but not MUSE (audio grade) So it's an easy upgrade replacement, but size is double of course.

It's stuff I buy cheap and upgrade cheaply....making a studio quality piece.

[forumuser840717]

Ah, of course. I'd forgotten about that. What a shame. I used to like their products. Solid, not exactly exciting but did what they said on the tin and kept doing it for years. Probably why they were able to be bought out. I wish he'd stop buying respectable companies and dragging them down to his level!

[James Perrett]

The problem with your mods is that you are ignoring the parts that probably make the biggest difference - the transformers.

[knave101]

I don't think it's a problem. It's a financial choice. I'm "hoping" that the Midas transformers are decent. I don't have a means to test them, so I leave them in. I'd like to know if anyone has tested them.

In the Peavey mod I mentioned I did swap out for Cinemag transformers, after sending in the Peavey originals to Cinemag to test. Dave Gerren (owner of Cinemag) was the one who informed me of the 1/3 cost of components for typical retail gear. https://forums.peavey.com/viewtopic.php?t=41946

Caps are a cheaper than steel. Though as you have said, it doesn't represent a "complete" upgrade, without addressing transformer shortcomings. I recently picked up a Warm WA67, WA87r2, and WA47. They use Wima and Polystyrene... which is slick and top notch. They gob the glue stick over the polystyrenes to keep them in place.

[Hugh Robjohns]

It may be that swapping a few caps makes an audible improvement... I don't know because I havent A-B'd an original and glitter-rolled version...

Without proper tests and measurements, though, its a flying blind exercise, and there are so many other likely weak points that will still limit performance ranging from the power supply, to the PCB and it's layout, to the I/O transformers, to the active devices, to the operational switches and pots... Usually, when things are built down to a price (or profit margin), the cut corners involve quite a lot more than just fitting cheaper caps.

As I said earlier, I don't want to stop the obvious pleasure you take in tinkering... I just remain unconvinced of the benefits. Recapping a quality vintage device would be a different matter of course... But possibly still out of the budget.

[Arpangel]

This is quite amusing, as I’m always trying to find new ways of making my gear sound really bad! and I don’t mean bad as in good, I mean, bad, like bad.

[Mike Stranks]

I'd be interested to know where 'knave101' is based...

My observations are that modding/"upgrading" gear - esp mics - is much more prevalent in the US than the UK...

[forumuser931182]

I once replaced every capacitor in my NAD 3020 amp ( about 50 capacitors and replaced with high quality audio ones ) and the results where spectacularly........ a complete waste of flipping time. Sounded exactly the same. Last time I bothered doing that.
Now I'm wondering if I should adjust the pump pressure on my espresso coffee machine. According to the coffee forums it should be 9 bar for perfect crema, not 8.5 or 9.5 bar. I think I will need to purchase a new high quality water pump! etc etc etc