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DjOverdose

Planning on changing amps from PP KT120 to SET 2A3

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On 7/7/2019 at 8:24 AM, Jeffrey D. Medwin said:

The rectifier tube should located be as FAR away as possible, from the input tubes. 

 

Here, we see just the opposite, close-to and smack dab between both of the input tubes.

 

 

 

 

Dude, please back off on being critical of everything and anything that doesn't fit your ideal design parameters.

 

If you see something you just can't contain yourself about, i.e. please start a new thread in Talkin' Tubes about the relative pros and cons of locating a rectifier in between two input tubes.  You can do the post without referencing any particular persons equipment they are building, or purchasing, or whatever.

 

When you do make such posts it would be helpful if you included a source besides your 40+ years of building experience as many on here have that, or what your ears tell you, as everyone has those along with a personal preference to go along with it.

 

Thank you.

 

 

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On 6/28/2019 at 9:11 AM, Marvel said:

I wouldn't want to waste a new WE 300B by doing that, though. Not at $1500 a pop... 😟

I thought they were half price for locals.  Made you look😝

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On 5/28/2019 at 7:59 AM, moray james said:

don't count on the published efficiency levels being accurate, you can expect them to be in the range of at least 2 - 3db hot and they are often measured at 1KHz.. Still a 2A3 can surprise most audiophiles, I am sure yours will also.

It is sensitivity, not efficiency.  It would depend how he has them placed in his room, and his room, on whether they will be right at spec, below,  or even above, right?

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On 6/28/2019 at 11:12 AM, Jeffrey D. Medwin said:

 

 If you have a good stereo amp design, simply listen to just ONE channel, playing one speaker, and decide for YOURSELF. 

 

I find that the local builder told you wrong.  I have often made the same mistake !! 

 

There really is no comparison to what monoblocks do,  after you do the above mentioned test I suggested. 

 

My 2019 KT88 will become the LAST stereo amp I EVER build for myself.

 

Jeffrey 

He said the cost difference didn't justify the added expense to HIM.

 

Simply say, all things being equal, you prefer monoblocks.

 

You don't know that his builder told him something "wrong."  He told him something you have a difference of opinion on.

 

Please keep this a nice friendly place, the one Maynard envisioned when he requested it be created

 

Thanks

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On 7/7/2019 at 12:47 AM, DjOverdose said:

almost done. just waiting for the cage to be finished. the builder say its somewhere around 3.5WPC to 4WPC.

PicsArt_07-07-01.46.16.jpg

PicsArt_07-07-01.45.21.jpg

That's some Mang, good for you.  So does that amp give you the option to go 300b, 45 like the one you described at the beginning of your thread?

 

If so you are going to be able to try a lot 9f every cool things!

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That's a lot of iron...going to be a beast to pick up.  My 2A3 amps only take a few minutes to warm up. I know you are certainly going to enjoy your new amp, no matter what anyone else says. 😉 

 

So, the smaller 9 pin is the driver on each side? I would like to know what your builder used, mostly out of curiosity. SETs can be so simple. I like it!

 

Bruce

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11 hours ago, dwilawyer said:

That's some Mang, good for you.  So does that amp give you the option to go 300b, 45 like the one you described at the beginning of your thread?

 

If so you are going to be able to try a lot 9f every cool things!

Hello. 

 

Yes he placed a switch at the back of the amp. If i remember it xorrectly it has 4 modes. thats for the voltage selector. 1st is 5V for the 300b and JJ2a3 40w

2nd is 4.5 and 3rd is 4V these are for the normal 2a3. then 4th was like 3.5v? cant remember actually the volatge. he just explained to me that the latter one is for the 45 since its the lowest voltage. so i can use option 1 to 3 for the 2a3. just obeserve which amongst it will sound sweet to my ears. 

 

Also if youll check the first picture, youll notice at the back of the 2a3 tubes theres a label that says 2a3. thats actually the filament switch? for 2a3 and 300b. as for the 45, ill just use the 2a3 and then set the correct bias. theres alot of things to fiddle with this amp. requesting the builder to give me a manual because i might forget about it after awhile. it also has a hum balancer on top and a gain controller at the back. 

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38 minutes ago, Marvel said:

That's a lot of iron...going to be a beast to pick up.  My 2A3 amps only take a few minutes to warm up. I know you are certainly going to enjoy your new amp, no matter what anyone else says. 😉 

 

So, the smaller 9 pin is the driver on each side? I would like to know what your builder used, mostly out of curiosity. SETs can be so simple. I like it!

 

Bruce

Yup it does have alot of iron. He builds the whole OPT and chokes from scratch so that he can customize the amp depending on the clients specification or request. 

 

the 9 pin is a 12at7. it drives the 5u4gb for the 2a3 power tubes.. the the middle one is a rectifier tube. forgot the tyoe though. 

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3 minutes ago, DjOverdose said:

Hello. 

 

Yes he placed a switch at the back of the amp. If i remember it xorrectly it has 4 modes. thats for the voltage selector. 1st is 5V for the 300b and JJ2a3 40w

2nd is 4.5 and 3rd is 4V these are for the normal 2a3. then 4th was like 3.5v? cant remember actually the volatge. he just explained to me that the latter one is for the 45 since its the lowest voltage. so i can use option 1 to 3 for the 2a3. just obeserve which amongst it will sound sweet to my ears. 

 

Also if youll check the first picture, youll notice at the back of the 2a3 tubes theres a label that says 2a3. thats actually the filament switch? for 2a3 and 300b. as for the 45, ill just use the 2a3 and then set the correct bias. theres alot of things to fiddle with this amp. requesting the builder to give me a manual because i might forget about it after awhile. it also has a hum balancer on top and a gain controller at the back. 

 The JJ 2A3-40 tube has a 2.5 VAC rated filament.   So does a Type 45 have a 2.5 VAC rated filament.  A 300B has a 5 VAC rated filament.   Current draws may vary between these different size and type tubes,  ( eg : the 2A3 and the 45 ) and that will effect the actual  operating voltage at the tube socket .

 

Jeffrey

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On 7/7/2019 at 9:24 PM, Jeffrey D. Medwin said:

The rectifier tube should located be as FAR away as possible, from the input tubes. 

 

Here, we see just the opposite, close-to and smack dab between both of the input tubes.

 

 

the rectifier tube is in the middle. the tubes infront of the 2a3 are driver tubes same with the 9pin.

 

 

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On 7/7/2019 at 11:49 PM, Schu said:

I bet you can't wait to hear it fire up for the first time... you're going to be impressed and happy.

 

I had the opportunity to take her home when i took this pictures. however the cage was not yet finished. so i decided not to bring her home not until the tube cage is finished. I have kids in the house, though im not concern about them having burns since i always listen at night. but im afraid that they might hit the tubes with a rubber ball when they are playing. hahaja that would be a bummer. 

On 7/8/2019 at 2:34 AM, Backfire said:

That looks really nice!  Very nicely built.

 

thank you... itll take quite awhile. need to brake in the power tubes and the opt... 

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13 minutes ago, DjOverdose said:

Yup it does have alot of iron. He builds the whole OPT and chokes from scratch so that he can customize the amp depending on the clients specification or request. 

 

the 9 pin is a 12at7. it drives the 5u4gb for the 2a3 power tubes.. the the middle one is a rectifier tube. forgot the tyoe though. 

The smallest 12AT7 is the input tube.  A 5U4GB is a rectifier tube, part of the power supply.  He used a Electro Harmonix, my personal favorite 5U4GB tube choice in 2019.  The EH  5U4GB takes 75 to 200 hours to fully break in BTW. 

 

The middle sized tube between the Input tube and the Finals/2A3 tube is a " Driver" tube, which drives the Finals tube. 

 

This is a three stage amp, Input ( 12AT7), next a  Driver ( not specified yet ) and Finals ( JJ 2A3-40).  The JJ 2A3 is among the best cost VS performance choice today in 2A3s when properly operated.

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11 minutes ago, Jeffrey D. Medwin said:

 The JJ 2A3-40 tube has a 2.5 VAC rated filament.   So does a Type 45 have a 2.5 VAC rated filament.  A 300B has a 5 VAC rated filament.   Current draws may vary between these different size and type tubes,  ( eg : the 2A3 and the 45 ) and that will effect the actual  operating voltage at the tube socket .

 

Jeffrey

err... to be honest when he was explaining the switches and selector to me, I just nodded. hahaha o really cant remember which is which. all i can remeber is that the one at the back is the voltage selector for a certain tupe of power tube. the other switcj is for the filament. the 3rd i need to change the bias every time i change to a different power tube... 

 

at this point i dont know if i can still use my kt120 power amp or if i will still be switching to it. 

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11 minutes ago, DjOverdose said:

err... to be honest when he was explaining the switches and selector to me, I just nodded. hahaha o really cant remember which is which. all i can remeber is that the one at the back is the voltage selector for a certain tupe of power tube. the other switcj is for the filament. the 3rd i need to change the bias every time i change to a different power tube... 

 

at this point i dont know if i can still use my kt120 power amp or if i will still be switching to it. 

 

 

By all means .......have your builder clearly write down what the switches do, and give it to you .   

 

Give the amp at least 75 hours use to allow it to settle in.  Stopping and starting it, normal use, is swell !!  Have fun.

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20 minutes ago, Jeffrey D. Medwin said:

The smallest 12AT7 is the input tube.  A 5U4GB is a rectifier tube, part of the power supply.  He used a Electro Harmonix, my personal favorite 5U4GB tube choice in 2019.  The EH  5U4GB takes 75 to 200 hours to fully break in BTW. 

 

The middle sized tube between the Input tube and the Finals/2A3 tube is a " Driver" tube, which drives the Finals tube. 

 

This is a three stage amp, Input ( 12AT7), next a  Driver ( not specified yet ) and Finals ( JJ 2A3-40).  The JJ 2A3 is among the best cost VS performance choice today in 2A3s when properly operated.

the tube in the middle was a 6n3c. i think he used that as a rectifier tube? 

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just want to share the whole amp set up... 

 

in the middle is my kt120 PP then on the left is the PSU of my Phono/line pre amp. (right) 

 

i had requested to have my pre amp to have to outputs so that when the time comes that I will have 2 power amps either a SET or an SS, it will be easier for me to switch. 

 

tubes used in the power amps are kt120s, 12at7, and ecc99. while for the pre amp PSU, regulator(?) was a 274b or 5u4g the n rectifier was el34. can also use either 6v6, 6ca7. for the phono/line all tubes are 12ax7.

PicsArt_07-09-10.47.09.jpg

PicsArt_07-09-10.56.30.jpg

PicsArt_07-09-10.54.52.jpg

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Dope From Hope Vol.16 No.1

I'd like to see this updated with Jubilee.

400114606_ScreenShot2019-07-09at10_01_27AM.thumb.png.c122cdf4c1c22c06be18fdb77379541d.png

 

 

 

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22 minutes ago, DjOverdose said:

the tube in the middle was a 6n3c. i think he used that as a rectifier tube? 

 

 

Hi, it can NOT ever be  a rectifier tube, as part of the middle audio-amplification stage  !!    A 6N3C is like a 6L6 power tube, Russian.   Look it up on line. 

 

The EH 5U4GB absolutely  IS the amp's rectifier tube., it is positioned on the amp chassis in the front, middle.    

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14 minutes ago, Jeffrey D. Medwin said:

 

 

Hi, it can NOT ever be  a rectifier tube, as part of the middle audio-amplification stage  !!    A 6N3C is like a 6L6 power tube, Russian.   Look it up on line. 

 

The EH 5U4GB absolutely  IS the amp's rectifier tube., it is positioned on the amp chassis in the front, middle.    

noted on this... will ask the builder what those tubes are for. really have no idea.... 😁 

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