400 WOPL Pics
- Thread starter George S.
- Start date
No schematics that I've seen as Joe who goes by Geppetto on the the forum, AKA the owner of WhiteOakAudio, most probably and rightfully considers his designs his intellectual property, But, start reading every post like I did before I ordered my kits. There are nuggets of gold on the most unlikely threads, thread crapping is not frowned on here. And, if you just want to repair a stock amp, just start a new thread. There are super experienced people here who can help you do that. Not me, I'm just a hobbyist. Start reading, most of what pertains to a 700 also works on a 400. This is a great forum!
Freecrowder,
There are some who feel that the PL400 does not warrant the necessary work to bring it up to WOPL specs. I personally like the PL400 very much, I think it has a softer edge due to the lower supply voltage.
If you are handy with electronics, you can order the fully assembled Control Board Kit from the website: http://www.whiteoakaudio.com/estore.aspx
Or, if you are really handy with a soldering pencil, you can save some money and build the Rev E6, or the newer Dual Mono Rev G1 Control Board yourself. This will remedy several design issues with the original Phase Linear control boards and improve the sound dramatically.
Additionally, you will want to replace the bulk capacitors because yours have reached their end of life. Look for PL400 Capacitor Assembly. Yours will be with a band that goes around the base of the capacitors or a strap that holds them in place in the aluminum cradle behind the power transformer. Finally, if you desire extremely clean and much more powerful sound from your amplifier, you should replace the 16 power transistors on the back of the amplifier. The currently available ON Semi devices are so much better than what Phase Linear had to use back in the 1970's.
Post some pictures of the inside and outside of your amp and those of us that like the PL400 will chime in. Ignore the folks that say you are wasting your time with the PL400.
There are some who feel that the PL400 does not warrant the necessary work to bring it up to WOPL specs. I personally like the PL400 very much, I think it has a softer edge due to the lower supply voltage.
If you are handy with electronics, you can order the fully assembled Control Board Kit from the website: http://www.whiteoakaudio.com/estore.aspx
Or, if you are really handy with a soldering pencil, you can save some money and build the Rev E6, or the newer Dual Mono Rev G1 Control Board yourself. This will remedy several design issues with the original Phase Linear control boards and improve the sound dramatically.
Additionally, you will want to replace the bulk capacitors because yours have reached their end of life. Look for PL400 Capacitor Assembly. Yours will be with a band that goes around the base of the capacitors or a strap that holds them in place in the aluminum cradle behind the power transformer. Finally, if you desire extremely clean and much more powerful sound from your amplifier, you should replace the 16 power transistors on the back of the amplifier. The currently available ON Semi devices are so much better than what Phase Linear had to use back in the 1970's.
Post some pictures of the inside and outside of your amp and those of us that like the PL400 will chime in. Ignore the folks that say you are wasting your time with the PL400.
- Joined
- Dec 7, 2020
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- 12
So does the kits bring it up to a modern SS design? hope I don't get myself in trouble here but the originals definitely have a dated SS sound to them. A little rough up high and low end that is a little weak. I would love to have a modern SS design with the classic looks of the 400II. I have hundreds of 15024/25 from the same lot numbers. Can you swap those with the stock xstrs w/o worrying about oscillation. Is it even worth it. Why does everyone go with 700's? Just for the power?
I think 700s are favored by many because it costs allot to do the full upgrade, and doesn't cost all that much more to do a 700 rather than a 400. Also, many people are concerned about resale value, they'll get a better return on investment in a 700 than a 400. As for me, I paid very little compared to eBay prices for my two 400s as I got them locally. And, I did all the work myself, so it was a fun project. Also, I'll never sell them, so I'm totally unconcerned about the "investment". And, a 400 was way more power than I'll ever need, so they are a better fit for me. Lastly, there are several amp builders on this forum who build for resale and clients, and man, they do outstanding work! I think these guys favour the 700s because it really show cases their work and the big amps are what the clients want. I can't address the rest of your questions because I just don't know.
It is a very modern, fully SPICE modeled SS design with great low end and very clear upper end and great sound stage when converted to full comp. Others that are less biased than I can chime in to give you other listening opinions. It would require installing the bulk cap kit, the control board (we have 2 choices) and the PL400 Backplane kit to get these features and results. The backplanes turn the original quasi comp into a full comp amp.
You can have a modern SS design and keep the classic looks of the 400II.
You can use the MJ15024 and MJ15025 but this community prefers MJ21195 and MJ21196 as better devices than the MJ15024/25 devices.
What else do you wish to know? I recommend you ask other questions from additional site members.
You can have a modern SS design and keep the classic looks of the 400II.
You can use the MJ15024 and MJ15025 but this community prefers MJ21195 and MJ21196 as better devices than the MJ15024/25 devices.
What else do you wish to know? I recommend you ask other questions from additional site members.
Free, I gave you the link to White Oak Audio in post #24. Joe sells the MJ21195G and MJ21196G output transistors on the website. If you bothered to look, you would know this. And why would they be anything other than a T03 package? That is what Phase Linear used in the 400 and 700 amps. The output protection is current limiting, very similar to the original design without the obsolete germanium transistors which are hard to source today. The input OPAMPs are OPA134PA, which are selected for ultra-low distortion, low noise, and high speed. They have a true FET input stage and a wide output swing, to within 1 V of the rails, allowing increased headroom and making it ideal for performance audio applications.
Here is the datasheet if you want to read about it: https://www.ti.com/lit/ds/symlink/o...l=https%3A%2F%2Fwww.ti.com%2Fproduct%2FOPA134
The input impedance to the WOPL amp is the same as the original Phase Linear amplifier, which would be 33K Ohms, minimum and typically 39K Ohms. A blank board, but why would you want do that? Have you seen the price of Joe's board kits? There is no way you could source the parts required in the materials list for less than Joe gets them in large quantities.
If you want to be a part of this group, you have to play by the rules. The rules are: 1) attempt to do some research yourself before asking the questions that would be obvious to someone who did a tiny amount of research. 2) buy the WOPL parts and then discover why they are as good as we say they are. 3) learn just like all of us did. We will help you, but we expect you try to learn yourself, first.
If you don't play by the rules, you will get flamed by other members, or at least get a HUH? as a response.
Here is the datasheet if you want to read about it: https://www.ti.com/lit/ds/symlink/o...l=https%3A%2F%2Fwww.ti.com%2Fproduct%2FOPA134
The input impedance to the WOPL amp is the same as the original Phase Linear amplifier, which would be 33K Ohms, minimum and typically 39K Ohms. A blank board, but why would you want do that? Have you seen the price of Joe's board kits? There is no way you could source the parts required in the materials list for less than Joe gets them in large quantities.
If you want to be a part of this group, you have to play by the rules. The rules are: 1) attempt to do some research yourself before asking the questions that would be obvious to someone who did a tiny amount of research. 2) buy the WOPL parts and then discover why they are as good as we say they are. 3) learn just like all of us did. We will help you, but we expect you try to learn yourself, first.
If you don't play by the rules, you will get flamed by other members, or at least get a HUH? as a response.
These two forums will cover pretty much anything you can think of, and much you might not. Great info.
WOPL Building | Phoenix Audio Community Forums (phxaudiotape.com)
WOPL Tips and Archive | Phoenix Audio Community Forums (phxaudiotape.com)
WOPL Building | Phoenix Audio Community Forums (phxaudiotape.com)
WOPL Tips and Archive | Phoenix Audio Community Forums (phxaudiotape.com)
- Joined
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- 12
Not sure what is causing all your ranting Mlucitt, but you see it all the time on forums. It becomes some peoples lives to find reasons to be so bothered. I come from DIY Audio forum where electrical designs are discussed in detail all the time and blank boards sold everyday. I understand that WO does not do that now but there is no harm in asking. As far as parts you have no idea what I might have available to me so mind your own business.
Anyway as far as purchasing WO's boards, Im sure there excellent, but from your response and attitude I will no longer even consider. You might want to have a discussion with the owners they probably don't appreciate the fact that you're hurting their business.
I will not bother anyone on this forum going forward. Goodbye
Anyway as far as purchasing WO's boards, Im sure there excellent, but from your response and attitude I will no longer even consider. You might want to have a discussion with the owners they probably don't appreciate the fact that you're hurting their business.
I will not bother anyone on this forum going forward. Goodbye
George, see if you can get him to lighten up. Everything I told him was factual, some was satirical humor. I pointed him to links that would answer his questions and he came back with more of the same questions because he did not bother himself to click on the link that I provided to him. Then I even provided another link to the OPAMP datasheet, so he could learn even more. He never said thanks...
I don't consider what I wrote to be ranting, but if he does, he does need to lighten up. I am on the DIY Audio forum as well, and this forum is different, not better or worse.
I thought this line of his was especially funny, "As far as parts you have no idea what I might have available to me so mind your own business." And he has no idea what parts are required for the WOA Control Board. Funny guy. Maybe trying to reverse engineer the WOA Control Board?
Sorry everyone, if I lost a sale of WOA parts to Freecrowder. He said, "Im sure there excellent" (his English) but how would he know? He did nothing to learn how excellent the WOA boards are in terms of quality and performance.
I don't consider what I wrote to be ranting, but if he does, he does need to lighten up. I am on the DIY Audio forum as well, and this forum is different, not better or worse.
I thought this line of his was especially funny, "As far as parts you have no idea what I might have available to me so mind your own business." And he has no idea what parts are required for the WOA Control Board. Funny guy. Maybe trying to reverse engineer the WOA Control Board?
Sorry everyone, if I lost a sale of WOA parts to Freecrowder. He said, "Im sure there excellent" (his English) but how would he know? He did nothing to learn how excellent the WOA boards are in terms of quality and performance.
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