I want to White Oak a Phase Linear 400 Series I

[laatsch55]

BOOM!!!!!!!!!!!!!!!!

 

[ksrigg]

BOOM, is what I don't want to happen. I was hoping for a little help and support, but I'll just read the service manuals and try to figure it out. It's written for tech who understand the basics of all this, which I don't, but maybe I'll get lucky..

 

[Gepetto]

We are here to help Sutton. I answered your PM about the bias setting.

 

[Gepetto]

Hi Sutton
Sent you an additional PM about the bias and offset measurements.

 

[ksrigg]

Thank you Joe. You are so very kind to explain to me how to proceed. I am very appreciative. One of these days I hope I can return the favor. Your knowlege and kindness arn wlingness to help a guy will never be forgotten. Thank you again...I'll let you know where the bias and DC offset are and where I am able to get the bias to settle. First I will add all the outputs, so I'll have to get my special "{butter knive" ready. Atually I use a little plactic tab from a file system to spread the thermal compound...and I have learned to use way less than I had originall used.. Lee is a master at that...

 

[Gepetto]

Spread sparingly Sutton. A little goes a long way, and gets everywhere

 

[laatsch55]

Now Sutton, I just got back to my computer, and we are always ready to help. You know that. So, how'd the bias and offset look ??

 

[kevin]

BOOM!!!!!!!!!!!!!!!!

LMAO...... I sure hope that dont happen to him..... He has got way to much stuff in his garage to kick, break and throw out in the yard..... That woild be a hell of a time to buy alot of really good stuff real cheap !!!!!!

 

[mlucitt]

I received and answered seven PMs from Sutton yesterday. I don't think he is hurtin' for help and support.

 

[kevin]

WOW.... I sure hope this one works for him...... If not...... It will not be lack of effort !! lol

 

[laatsch55]

Sounds like it has a fighting chance with everything cool without the drivers in.

 

[ksrigg]

Ie not gotten any further. I have spent the day with the missus...watching TV, while I did apply thermal compound to the output transistors. I also cleaned the transistors which came from the amp originally. In the morning, I will put all the outputs in the amp and test bias and offset. I am just happy with the knowledge to do the testing. I think it should be easy enough. I just hope I am able to adjust the bias and don't run into the problem of 350mv being out of the range of the pot's ability to adjust it..

I am just basking in the glow (blue) that this amp actually produced music. That is new for me, but hopefully the third time is the charm. I really hope everything goes without a hitch and I am able to add all the ouputs, adjust the bias to 350mv for each channel, and the DC offset is close to zero...and that the amp counds amazing. With just the drivers installed, it did sound a little distorted...not really terrible, but pretty noticeable...

Next I gotta decide on whether to work on the RSD or the PL 700B. I may just try to get both of them going at the same time. Making the cords should be fairly straightforward, but finding out how to set bias on it will be tough... I have the replacement 2N3773's in hand, but the drivers were backordered from Mouser...which means the outputs for the 700B were also backordered. I may have to stay with the original RCA 909's as drivers in the RSD... I just don't know. The RA 909's are used as drivers in the RSD and I had thought of using On Semi MJ15024G as a replacement for them. I do not have a schematic for the amp...so I may have to stick with the original drivers. I was able to buy new production 2N3773's and got On Semi brand from Mouser. What are the possible replacements for the RCA 909 in the driver position?

Thanks again Joe and everyone else...Mark, Lee and others.....for all the help.. I am just on Cloud Nine right now...

 

[laatsch55]

What's an RSD??

 

[laatsch55]

What are the possible replacements for the RCA 909 in the driver position?

Are they NPN?? If so, the RCA 410's, 2N5039's.....

 

[ksrigg]

Lee,

It's the Recording Studio Designs 800b...the amp which was made in Britain in 1973. There is a thread about it in the AMPS topic. I'm just trying to figure out the best transistors to use in it, as I try to being it back to the future. Any help will be appreciated.. I can't find much out about this amp at all. Just a few mentions on the internet. Looks like a PL 400 clone using 2N3773 outputs...I can run it in mono or stereo, so I may use it for sub duty. Gotta make up some cords first, and I wanted to put new transistors in her as I'll bet the 40 year old ones might be tired..
How can I tell if they are NPN or PNP?

I thought I was getting a cough and I was right. Started really hackin in the night, and think I have the croup....started taking Cipro, so hopefully I can get over it in a few days. I feel like crap..

 

[laatsch55]

To check for NPN ness, put positive lead of DMM< on base and the negative on the collector and emitter, should get a .400 to .650 volt DC reading in diode test mode. A PNP will be opposite, neg on base pos on collector and emitter. are the 3773's Motorola?

 

[laatsch55]

Sutton, you can run MJ 15024's or MJ 21196's in that for outputs. The 3773 looks like a good driver.

 

[ksrigg]

Hell Lee, I wss going to put new 2N3773 in the amp for outputs, and go with the same srivers as the Phas Linear the MJ15024G. The MJ21196G are out of stock at Mouser and have been backorder for about 2 weeks.. I have enough of them on order to use as drivers. I also ordered them as outputs for the 700B..

So you would use the 3773 for drivers and the 15024 or 21196 as outputs? Looks like I had it backwards...I should send it to you. You would have a ball playing with it. It is a monster. Transformer is as big as one from a 700B.....It appears to be very solidly built. I am going to have to replace lamps in the meters too, but getting to them won't be really easy. I'll have to take the amp apart to get to them..Did you see the pictures of the amp in the RSD thread under the AMP topic?

See what you think...A British tank...Can't remember if the outputs are Motorola or not. The drivers were RCA. I do remember that..I feel so bad, and it's raining here. I really don't feel like walking out to the building an looking right now, but I will later in the day...If you want any close-up pics, let me know, and I'll try to get some close-ups..

 

[laatsch55]

I remember it now. I would use the 3773's as drivers, but I do have a lot of 5039's and 410's here also that would work just as well. So there has beena run on 21196's eh?? I think I still have a hundred or so, time to restock.

 

[ksrigg]

On the 400 Lee, I listened to the amp with the DRIVERS installed, but no OUTPUTS...I think she will be fine. I just need to add the OUTPUTS and set bias and check offset. I hate that this cough has gotten me, or I'd already have it done, and be cranking out the tunes...She looks really nice with the blue LEDs...I still like the white LEDs for the original look, but there is something cool about the BLUE...Maybe it's a McIntosh thing....or a Marantz thing...This one has a very hot transformer too, os I'm anxious to determine the output on this one...