Klark Teknik KT-2A

[AUDIO FREQ]

Oh I mean the pot on the chassi, Pre-Emphasis.

I found a C14 but it’s a 1μF electrolytic so I don’t think the KT-2As components are labeled the same as on the LA-2A schematic but I’m not sure…

Yeah you’re probably right!
I found 3 ceramics which has,47pf and 2x 471pf.

Which is the closest caps I can find to match the LA-2As variable capacitor range.

Did you find if those were it?

 

[AUDIO FREQ]

Maybe one of the pots on the bottom of the picture

 

[mattenylander]

Did you find if those were it?

I haven’t actually had the time to test it yet, hopefully I can give it a try this weekend. I reached out to Klark teknik but they couldn’t provide me with a schematic or which capacitors was wich.

Do you happen to have a picture of the PCB underneath as well?
Would be interesting to see if it’s possible to follow the trails.

 

[DanKoVO]

The red one at the bottom (22nf) and the two yellow ones above it (100 nf) are directly in the signal path. The two yellow ones next to your thumb are in the sidechain, no point in changing these IMO.

Is this what you ended up using for your mods? Mouser Cart

 

[Tubetec]

If the KT2A is anything like the the EQPKT , theres a ton of out of band garbage between 50-100khz from the SMPS , I use 192khz sample rate with REW to look at the output ,
I'm doing a linear off board psu for mine ,

 

[living sounds]

Is this what you ended up using for your mods? Mouser Cart

I used what I had around, mostly Solen Fast, but I think in one of them I used a WIMA cap or two.

 

[living sounds]

If the KT2A is anything like the the EQPKT , theres a ton of out of band garbage between 50-100khz from the SMPS , I use 192khz sample rate with REW to look at the output ,
I'm doing a linear off board psu for mine ,

I did look at it with the scope and found some but not so much out of band SMPS garbage. Still have the linear PSU on the to do list, but without a schematic of the KT2A it's not so much fun with these high voltages...

 

[Tubetec]

Ive been able to look a bit closer at the ht regulator circuit used in the EQP,
both 12ax7 and 12au7 HT rails are derived are after it ,

There doesnt seem to be any regulators on the KT-2 main board so most likely there on the PSU pcb ,
you should be able to check the supply voltages at the 5 pin molex in the middle of the board then you can estimate the total currents .

 

[living sounds]

Ive been able to look a bit closer at the ht regulator circuit used in the EQP,
both 12ax7 and 12au7 HT rails are derived are after it ,

There doesnt seem to be any regulators on the KT-2 main board so most likely there on the PSU pcb ,
you should be able to check the supply voltages at the 5 pin molex in the middle of the board then you can estimate the total currents .

Yes, I'm pretty sure that the main HT voltage goes through an RC filter on the PSU PCB and then to the audio PCB. But there are other voltages. I already got zapped once poking around at that board.

 

[Tubetec]

I always add extra insulation to the + multimeter probe tip , so as to reduce the possibility of an inadvertant short while probing around ,
It also good practice to crock clip the - lead to ground ,
now your probing single handed , again in the case of inadvertant contact with high voltage , you minimise the chance of current flowing across the chest .

be safe ,dont be sorry .

 

[shabtek]

xfmr is designed AND engineered in UK...sowter winding plan? but where is it made?


I know it is just a label stuck to the tin for those who care...

Mastering lab mod if you know what's up

 

[Tubetec]

Its probably been a very long time since anything Midas had transformers in it , thats not to say they dont have the in house knowledge to design one themselves and have it produced in China .

The screening can on the EQP input transformer is very thin , less than 1mm , Im not sure how to determine if its mumetal or not . The input circuit also has a 2x 10k:1k attenuation network pre transformer so as what ever you drive it with doesnt see too low a load .
Maybe that upsets the EQ circuit drive .

 

[DanKoVO]

I just finished up the mod using the parts from my Mouser cart. Sounds great! For a few bucks it was worth it to me. Especially after investing in a Kenetek and old RCA's.

This took about 1 hour from start to finish for anyone interested. For someone without ADD it may go quicker! The trickiest part was solder-sucking after removing the original components. Had to be careful not to burn the board and went slow and steady using braided copper along with a sucker.

 

[living sounds]

I just finished up the mod using the parts from my Mouser cart. Sounds great! For a few bucks it was worth it to me. Especially after investing in a Kenetek and old RCA's.

This took about 1 hour from start to finish for anyone interested. For someone without ADD it may go quicker! The trickiest part was solder-sucking after removing the original components. Had to be careful not to burn the board and went slow and steady using braided copper along with a sucker.

It looks like you kept the big yellow 10uf cap before the output trafo. I thought that was one of the worst offenders.

 

[DanKoVO]

It's the Nichicon replacement from my mouser cart. I swapped one big yellow one for another!

I did run into a problem while recording tonight. All was fine then an hour in the sound got distorted and it stopped compressing. Still passing audio, gain works, no compression. Will need to troubleshoot that since the opto cell is new, and I wouldn't think the mods could cause that specific issue.