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DIY Amplifiers - What have you built and is it a keeper?


Curious_George
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Just wondering what members have built for use with their Klipsch speakers. 
 

I’ve restored (and modified) quit a few Phase Linear amps, and for some reason, have a soft spot for them. Currently, I have about 14 various models. Depending on the model and series, I prefer some over others. I have a late model 700B with 3 prong power cord and dual primary power transformer. It has been kept stock for nostalgic purposes. 
 

I also have another 700B chassis that I am using as a “test mule” to design new amp circuits. The amp topology in it now has 10 T03 outputs per channel (just like a normal 700), but the pre-driver and driver stage are operated class A, not class B. The output section is full complementary. The input driver board is a balanced input design with a slew rate of about 40V/uS. Similar to a 700B for output power: 350 watts per channel into 8 Ohms, mono 1.1 kilowatt 8 Ohms. 
 

Krell KSA50 clones - These amps sound pretty good. Very dynamic and revealing.

 

AB International 600LX amps - one stock, one modified. Decent amp for the money. Easy to modify, triple output design. 

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That is a subjective answer. I would say that a class D amp would be one of the worst for any speaker, except a sub, but that is my opinion. 
I partially agree with your answer though. I prefer the Series I over the Series II. The Series I, if rebuilt and modified for full complementary output stage, can sound extremely good and are quiet. The Series II were noisy and a bit more reliable than the earlier Series I, but that was mainly due to the better output transistors used in the late 70’s compared to the early 70’s. 
 

If you have never heard a PL 400 or 700 modified and brought up to modern “standards” you would be amazed at how good it can sound, even on Klipsch speakers. 
 

 

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2 hours ago, ClaudeJ1 said:

The KRELLs are the Boss!

 

 

Dimensions:
40 miles width
78,000 feet (14.8 miles) height
400 modules identical to the above
Casing: Solid Krell Metal 26 inches thick
Warranty: Self maintaining
Power Supply: 9,200 Thermonuclear reactors
Remote control: THE SUBCONSCIOUS ID!!

 


Monitors: Analog meters as God intended!

Be warned or die!!

 

As you were - Langston

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1 hour ago, Curious_George said:

f you have never heard a PL 400 or 700 modified and brought up to modern “standards” you would be amazed at how good it can sound, even on Klipsch speakers. 
 

I was speaking of the original Flame Linear, not the modified version you speak of. How else would I know. Much like you have never heard a Hypex on horns, like I did on the $40,000 Sadurni Staccatos, which convinced me to go with the NC-400 you never heard either. I guess that just makes us even.

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We’re not even, but I know from perusing this forum that you come across as brash sometimes and that’s ok. All the forums are alike in that regard. 
 

I’m not a proctologist, but I know an a$$hole when I see one. One of my favourite sayings…

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7 hours ago, Curious_George said:

We’re not even, but I know from perusing this forum that you come across as brash sometimes and that’s ok. All the forums are alike in that regard. 
 

I’m not a proctologist, but I know an a$$hole when I see one. One of my favourite sayings…

I've never known Claude J to be anything other then a gentleman that is willing to help anyone that ask. Perhaps you two just took postings wrong. Your postings are very entertaining and helpful as well. Always glad to have another diy'er on the forum. 

 

As far as amplifiers, I am not as critical of them as I once was. I can enjoy all the different classes. 

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Hi I'm new to this forum, any forum actually but very glad I joined. I'm very interested in building a DIY amplifier for my system maybe 2 amps 1 for 7.2 home theater and the other for my Heresy's to listen in hi fi stereo. Any suggestions, pointers, advice and guidance would be greatly appreciated. I am on a very low budget so can't spend very much $ but have lots of enthusiasm.

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11 hours ago, babadono said:

?? WTF ??


I'll tell you WTF... your "gentlemen" Mr. Claude elevated the level of the conversation by his presumption and tone, but I am certain he is well aware of it. It seeps out quit often. I expressed an opinion about his fondness for class D amps (which I must admit, knew would lead to some anecdotal story about multi-thousand dollar equipment he had experienced) only after his very broad dismissal of Phase Linear amps for Khorns. Do I care? No. Everyone has their favorite amps. I just thought I'd let Claude know what I thought at that moment. No hard feelings either way. 

 

As I have said for many years, being on these forums is like being back in high school a lot of times... entertaining to say the least. Fortunately, there is a good amount of constructive info as well.  

 

Gotta run, I just heard the bell.

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6 minutes ago, Curious_George said:

Do I care? No.

Sure seems like you do.......

But anyway, I built a Class D amp based on the TI 3255 eval board. I run my Jube bass bins with it currently. I rebuilt several Crown D75s and switch them in and out on the 402 horns with my old Boulder 500. The Crowns also do outdoor patio duty.

Currently I am attempting to modify one of the Crowns to be a "current" drive amp as opposed to voltage, it's a ******. Not working yet, of course this is done in my "spare" time. In the future I would like to build some of the PASS ACA amps and some of the Hypex NCores

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If you interpret "tone" into what is written on forums, you are asking to be offended.  A while back, I asked Claude a question and his reply seemed harsh to me. While I was busy feeling hurt, he ran calculations for the design I asked about and help me out considerably. I read too much into it. 

Just my experience. 

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I have some limited experience with ICE Power modules and Sunfire amps. The ICE Power was back in 2004 or 2005 when they were trying to get a foothold in the US with a name brand. Deal never went through, but the amps / modules passed all of our testing. There was no protection circuitry whatsoever, so we had to design short circuit, over current and DC Offset to withstand the mobile environment. 

 

The Sunfire amp, as you probably already know is not really a class D amp, but a switching power supply that tracks the music signal and delivers just enough voltage and current to the analog amp to operate (the amp) in an efficient manner. Ingenious concept if you ask me. 

 

Have not built any class D kits. I'm a die hard analog fan.     

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3 hours ago, Gcyrusday said:

Hi I'm new to this forum, any forum actually but very glad I joined. I'm very interested in building a DIY amplifier for my system maybe 2 amps 1 for 7.2 home theater and the other for my Heresy's to listen in hi fi stereo. Any suggestions, pointers, advice and guidance would be greatly appreciated. I am on a very low budget so can't spend very much $ but have lots of enthusiasm.

 

What is your budget? Do you want analog or class D? Power output?

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I have built several amps for both speakers and phones. Tube amps include Elekit TU-8600S and VTA M-125 monoblocks and KGST for electrostatic headphones.
Solid state amps I have built are Pass DIY M2x, F5, and ACA, also DIY Krell KSA-5 clone for dynamic, and KGSSHV Carbon for electrostatic phones.
For high efficiency speakers, the Pass M2x is outstanding but it does generate some heat.
I am in the process of building a class A SIT amp. I hope it will dethrone the M2x for mids.

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52 minutes ago, Curious_George said:

I have some limited experience with ICE Power modules and Sunfire amps. The ICE Power was back in 2004 or 2005 when they were trying to get a foothold in the US with a name brand. Deal never went through, but the amps / modules passed all of our testing. There was no protection circuitry whatsoever, so we had to design short circuit, over current and DC Offset to withstand the mobile environment. 

 

The Sunfire amp, as you probably already know is not really a class D amp, but a switching power supply that tracks the music signal and delivers just enough voltage and current to the analog amp to operate (the amp) in an efficient manner. Ingenious concept if you ask me. 

 

Have not built any class D kits. I'm a die hard analog fan.     

Was die hard class A only one time myself but have since been convinced all classes can sound outstanding when the design works. You should try one of the TPA3255 boards one can buy on ebay and build a linear supply for it. I can almost guarantee you will be pleasantly surprised. I have two of them with linear supplies. One an original Texas Instrument board and one from China bought on Ebay. Both sound extremely good and equal. Best bass of all my amps with great vocals and soundstage.   

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38 minutes ago, henry4841 said:

You should try one of the TPA3255 boards

I agree. For anyone willing to audition the TPA3255 "sound" Get an Aiyima A07 amp they're like 63.00 right now on Amazon. Listen for a few weeks and then return it, that way it won't cost a sent. Then plan your own DIY build.

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