700 Series II Clair Originality

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#1
I'm at a crossroads right now since I'm getting ready to start dicking with some of these Clair 700 II's. As much as I'd love to WOPL them (I still may do a few), I am concerned about keeping some of them original or nearly original. I know there are proponents for both sides and I am in agreement on all the arguments so I am asking for input on the upgrade of the PL-36 boards (I see the kits for caps and diodes on the bay). What is needed to get these boards up to todays standards. I don't want to have to do any crazy shit to get them to operate correctly after changing out components so keep ideas to replacement of stock components. I'm also looking for ideas on the backplanes. I have a stock of the MJ21195/96's and Sil Pads, so I'd like to keep using those. Also is there a benefit to putting the 15,000 uf Bulk caps in these. Will I create issues by putting in bigger caps and bridge rectumfiers. Ed gave me ALOT of info on the series II amps and I should have recorded it. I have CSR (Can't Remember Shit), so maybe we can capture the necessary things here. Sanding and painting the top and bottom covers is a must as is replacing any corroded hardware. I'll come up with a checklist/traveler for each amp of the necessary items and use that as a guide. I am going to start with a consecutive serial numbered set when I get back from vacation/working on the house in Arizona. I'm leaving Friday morning. So, IDEAS??? Remember, these are full comps already.

1. PL 36 rework

2. Original Backplane rework

3. Output Trans. Ideas

4. Bulk caps to 15,000 uf/160volt ????

5. wiring issues or rewiring?


I'm not trying to be rude but can we keep the riff-raff sidetracking to a minimum? It's hard to glean info out of 600 pages of me being a knucklehead and you guys egging me on :)
 

Northwinds

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#2
This is what Ed said they needed to me yesterday, I may have some shit wrong

IC 8pin if it is a LF356 in it, change to a LF351???

If you see 7.5k ohm's anywhere that are ROCKWOOD replace them. If they are TRW they are ok

Something about big resistors... 7.5k 10% 1w change to 2w, there is 2 of them???

He said a year (1981??? Had bad version transistors, bad run??). He said the 24/25's?? were great if Motorola???

He talked about so much stuff that was over my head Perry, it was fascinating

He also mentioned something coming of the RCA jacks, if gold wires it was not cool???

From what he said, this is similar to a WOPL already so just keep 'em stock but change whatever else like upgrading to 95/96s. The big caps well who knows how long they will last but these were maintained well (it looks like) aside from some rust from the climate. Mine is actually clean inside, I don't see corrosion really. It's weird looking inside one when your used to seeing backplanes LMAO!!! These are definitely cool

DC protection should also be installed of course

Hopefully Ed will see this
 
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#3
Excellent

I'm at a crossroads right now since I'm getting ready to start dicking with some of these Clair 700 II's. As much as I'd love to WOPL them (I still may do a few), I am concerned about keeping some of them original or nearly original. I know there are proponents for both sides and I am in agreement on all the arguments so I am asking for input on the upgrade of the PL-36 boards (I see the kits for caps and diodes on the bay). What is needed to get these boards up to todays standards. I don't want to have to do any crazy shit to get them to operate correctly after changing out components so keep ideas to replacement of stock components. I'm also looking for ideas on the backplanes. I have a stock of the MJ21195/96's and Sil Pads, so I'd like to keep using those. Also is there a benefit to putting the 15,000 uf Bulk caps in these. Will I create issues by putting in bigger caps and bridge rectumfiers. Ed gave me ALOT of info on the series II amps and I should have recorded it. I have CSR (Can't Remember Shit), so maybe we can capture the necessary things here. Sanding and painting the top and bottom covers is a must as is replacing any corroded hardware. I'll come up with a checklist/traveler for each amp of the necessary items and use that as a guide. I am going to start with a consecutive serial numbered set when I get back from vacation/working on the house in Arizona. I'm leaving Friday morning. So, IDEAS??? Remember, these are full comps already.

1. PL 36 rework IC 8pin if it is a LF356 in it, change to a LF351, 7.5k ohm's (ROCKWOOD) replace them.)(TRW are ok). 7.5k 10% 1w change to 2w, there are 2 of them (bottom of board).




2. Original Backplane rework

3. Output Trans. Ideas

4. Bulk caps to 15,000 uf/160volt ????

5. wiring issues or rewiring?
DC Protection

I'm not trying to be rude but can we keep the riff-raff sidetracking to a minimum? It's hard to glean info out of 600 pages of me being a knucklehead and you guys egging me on :)
That's excellent Ron, now I remember some of it.
 

Northwinds

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#4
Pick me up, I could use a vacation in Arizona and I do custom hardwood flooring for a living (did), exterior work (except vinyl/aluminum siding!! Fuck that shit and glad we don't have it), sill plates, floor joists, making house trim, painting etc.... I became quite the Bob Vila these last few months...

I work for board/food/buzz LMAO!!!!

EDIT: That PL turnoff thump is annoying, need to get rid of that to!!
 
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Northwinds

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#5
Perry, Ed also told me the transformers in these amps are the hot ones everyone hopes to get in their 700B. If they did not test at 700w single channel 1kHz at 4ohms?? they were sent back. He said many of these were sent back until they came back right so your correct, these have a lot of ass. Pretty cool info Ed has indeed
 
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The transformers or transistors? As for the turn off thump, I think there was a blurb in the manual. I'll want to fix that too.......
 

WOPL Sniffer

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#7
I'm at a crossroads right now since I'm getting ready to start dicking with some of these Clair 700 II's. As much as I'd love to WOPL them (I still may do a few), I am concerned about keeping some of them original or nearly original. I know there are proponents for both sides and I am in agreement on all the arguments so I am asking for input on the upgrade of the PL-36 boards (I see the kits for caps and diodes on the bay). What is needed to get these boards up to todays standards. I don't want to have to do any crazy shit to get them to operate correctly after changing out components so keep ideas to replacement of stock components. I'm also looking for ideas on the backplanes. I have a stock of the MJ21195/96's and Sil Pads, so I'd like to keep using those. Also is there a benefit to putting the 15,000 uf Bulk caps in these. Will I create issues by putting in bigger caps and bridge rectumfiers. Ed gave me ALOT of info on the series II amps and I should have recorded it. I have CSR (Can't Remember Shit), so maybe we can capture the necessary things here. Sanding and painting the top and bottom covers is a must as is replacing any corroded hardware. I'll come up with a checklist/traveler for each amp of the necessary items and use that as a guide. I am going to start with a consecutive serial numbered set when I get back from vacation/working on the house in Arizona. I'm leaving Friday morning. So, IDEAS??? Remember, these are full comps already.

1. PL 36 rework IC 8pin if it is a LF356 in it, change to a LF351, 7.5k ohm's (ROCKWOOD) replace them.)(TRW are ok). 7.5k 10% 1w change to 2w, there are 2 of them (bottom of board).




2. Original Backplane rework

3. Output Trans. Ideas

4. Bulk caps to 15,000 uf/160volt ????

5. wiring issues or rewiring?
DC Protection, TURN OFF THUMP repair,

I'm not trying to be rude but can we keep the riff-raff sidetracking to a minimum? It's hard to glean info out of 600 pages of me being a knucklehead and you guys egging me on :smile:
 

oldphaser

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#8
Perry, Ed also told me the transformers in these amps are the hot ones everyone hopes to get in their 700B. If they did not test at 700w single channel 1kHz at 4ohms?? they were sent back. He said many of these were sent back until they came back right so your correct, these have a lot of ass. Pretty cool info Ed has indeed
Ron,

According to Dean it was 700W single channel driven into 15KHz @ 4 ohms.

Ed
 

oldphaser

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#10
The transformers or transistors? As for the turn off thump, I think there was a blurb in the manual. I'll want to fix that too.......
There was a service bulletin:
SUBJECT: Front End IC's in Models 400II and 700II PC Boards

"In the first year production runs of the models 400 and 700 Series Two PL36 PC driver boards we used a TO-99 packaged Fairchild or Signetics LF356 front end BI-FET op amp. This particular IC package was found to cause an unacceptable turn-off "thump" in some amplifiers. We later discovered and used in production a 8-pin mini-DIP packaged LF356 (National) which reduced this thump.

As of about May 1979 all production runs of the PL36 driver board began using a National LF351 IV (Phase Linear part number 126-0114) which was found to have a better slew rate, slightly lower distortion, and substantially reduced the delayed turn-off thump. They are also cheaper.

If a model 400 or 700 Series Two amplifier has excessive delayed turn-off noise the front end IC's should be replaced with the LF351. These are a direct retrofit device and require no additional modification to the PC board."

NOTE: When replacing the LF356 IC with LF351's you will also need to replace the 2.4K/5W dropping resistors (R1 and R2) with 7.5K/5W resistors.I might suggest installing a 8 pin gold IC sockets to allow for easier removal and substitution. This will also help reduce the chance of lifting traces from the pc board due to repeated de-soldering.

Ed
 
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oldphaser

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#11
Ed, can you explain the "Single Channel" to me? It implies they are MONO????
They are not MONO. The amplifier just barely does 700 watts into a 4 ohm load single channel driven. It is highly unlikely it would do 700 watts a channel both channels driven. The limiting factor would be the power supply.

Ed
 

WOPL Sniffer

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They are not MONO. The amplifier just barely does 700 watts into a 4 ohm load single channel driven. It is highly unlikely it would do 700 watts a channel both channels driven. The limiting factor would be the power supply.

Ed
RON??? Fire it up.......
 

oldphaser

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#14
This is what Ed said they needed to me yesterday, I may have some shit wrong

IC 8pin if it is a LF356 in it, change to a LF351???

If you see 7.5k ohm's anywhere that are ROCKWOOD replace them. If they are TRW they are ok

Something about big resistors... 7.5k 10% 1w change to 2w, there is 2 of them???

He said a year (1981??? Had bad version transistors, bad run??). He said the 24/25's?? were great if Motorola???

He talked about so much stuff that was over my head Perry, it was fascinating

He also mentioned something coming of the RCA jacks, if gold wires it was not cool???

From what he said, this is similar to a WOPL already so just keep 'em stock but change whatever else like upgrading to 95/96s. The big caps well who knows how long they will last but these were maintained well (it looks like) aside from some rust from the climate. Mine is actually clean inside, I don't see corrosion really. It's weird looking inside one when your used to seeing backplanes LMAO!!! These are definitely cool

DC protection should also be installed of course

Hopefully Ed will see this


Ron,

Yes indeed if the dropping resistors (located on the Malco pins on the side of the pc board closest to the power supply capacitors) are Rockwood brand 7.5K resistors (R1 & R2).... they will need to be replaced as a matter of course due to there higher than normal failure rate. The TRW brand were not a problem.

Likewise, the 7.5K/2W resistors (R101 and R201) should also be replaced as a matter of course. They too have a higher than normal failure rate.

In either case, for the 7.5K resistors R1/R2 or R101/R201 you will more than likely find that they are reading higher than the upper limit of the +/-10% tolerance (i.e. 8250 ohms). Once they start to read greater than approximately 9.5-10K ohms you will experience problems with your amplifier.

1982 was also a bad year for the Motorola MJ150254's and MJ15025's. They too should be replaced as a matter of course. NOTE: The way to identify the year is by the 4 digit date codes (i.e. 8213, 8236, 8252) located on the transistor.

Any twisted pair wiring that runs to the pc board from the volume pots IMHO should be replaced with shielded wire. To illustrate the difference..... listen to the noise floor of your amplifier with nothing plugged into the input. Carefully observe the noise floor while rotating the volume pot clockwise through your speakers. The twisted pair is noisiest when the volume pot is at 12 oclock and they gets quieter as your rotate to the full clockwise position. NOTE: I also recognize that this is not a normal way to observe noise since you are not shorting the input (as would be the case with shorting jacks or the volume pots fully counter-clockwise). In this case, with twisted pair you are more than likely picking up any ambient RF.

Ed
 
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WOPL Sniffer

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Ron,

Yes indeed if the dropping resistors (located on the Malco pins on the side of the pc board closest to the power supply capacitors) are Rockwood brand 7.5K resistors (R1 & R2).... they will need to be replaced as a matter of course due to there higher than normal failure rate. The TRW brand were not a problem.

Likewise, the 7.5K/2W resistors (R101 and R201) should also be replaced as a matter of course. They too have a higher than normal failure rate.

In either case for the 7.5K resistors R1/R2 or R101/R201 you will more than likely find that they are reading higher than the upper limit of the +/-10% tolerance (i.e. 8250 ohms). Once they start to read greater than let's say 9.5-10K ohms you will experience problems with your amplifier.

1982 was also a bad year for the Motorola MJ150254's and MJ15025's. They too should be replaced as a matter of course.

Ed
Great info Ed, I'll add it to the list. I'll have to order some R101/201 7.5K/2 watt (I'll get the good ones). And the resistors on the malco's. The ones I have seen have been TRW's so far.
 

oldphaser

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#16
Perry,

I made some edits while you were posting your response. Please read my previous post again.

Thanks!
Ed
 

WOPL Sniffer

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#17
I am asking for input on the upgrade of the PL-36 boards (I see the kits for caps and diodes on the bay). What is needed to get these boards up to todays standards. I don't want to have to do any crazy shit to get them to operate correctly after changing out components so keep ideas to replacement of stock components. I'm also looking for ideas on the backplanes. I have a stock of the MJ21195/96's and Sil Pads, so I'd like to keep using those. Also is there a benefit to putting the 15,000 uf Bulk caps in these. Will I create issues by putting in bigger caps and bridge rectumfiers. Ed gave me ALOT of info on the series II amps and I should have recorded it. I have CSR (Can't Remember Shit), so maybe we can capture the necessary things here. Sanding and painting the top and bottom covers is a must as is replacing any corroded hardware. I'll come up with a checklist/traveler for each amp of the necessary items and use that as a guide. I am going to start with a consecutive serial numbered set when I get back from vacation/working on the house in Arizona. I'm leaving Friday morning. So, IDEAS??? Remember, these are full comps already.

1. PL 36 rework
1. IC 8 pin if it is a LF356 in it, change to a LF351( gonna try AD825's on Brown Dog adapters.
2. 7.5k ohm's (ROCKWOOD) replace them (they are on the Malco Pins-TRW are ok).
3. 7.5K 2 Watt resistors R1/R2 or R101/R201 Replace,When replacing the LF356 IC with LF351's you will also need to replace the 2.4K/5W dropping resistors (R1 and R2) with 7.5K/5W


4. Original Backplane rework

5. Output Trans. Ideas MJ21195/96

6. Bulk caps to 15,000 uf/160volt ????

7. wiring issues or rewiring?
DC Protection, TURN OFF THUMP repair (OpAmp replacement may cure this) Get rid of twisted pairs on input wiring.

I'm not trying to be rude but can we keep the riff-raff sidetracking to a minimum? It's hard to glean info out of 600 pages of me being a knucklehead and you guys egging me on :smile:
6 WOPL 1000's (2 left), 16 Clair Bros Phase Linear 700 II's, Phase Linear 4000 Preamp, Michael Lim RP6/RP8 custom Turntable, Onkyo P-304 Pre, Epicure 20+, CornScala's, Epicure 3.0 (clones I built)
 
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WOPL Sniffer

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#19
Were getting a good base together. I'll put together a checklist when I get back from Arizona. I think I got everything to do a set (and then some).
 

Gepetto

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#20
I am asking for input on the upgrade of the PL-36 boards (I see the kits for caps and diodes on the bay). What is needed to get these boards up to todays standards. I don't want to have to do any crazy shit to get them to operate correctly after changing out components so keep ideas to replacement of stock components. I'm also looking for ideas on the backplanes. I have a stock of the MJ21195/96's and Sil Pads, so I'd like to keep using those. Also is there a benefit to putting the 15,000 uf Bulk caps in these. Will I create issues by putting in bigger caps and bridge rectumfiers. Ed gave me ALOT of info on the series II amps and I should have recorded it. I have CSR (Can't Remember Shit), so maybe we can capture the necessary things here. Sanding and painting the top and bottom covers is a must as is replacing any corroded hardware. I'll come up with a checklist/traveler for each amp of the necessary items and use that as a guide. I am going to start with a consecutive serial numbered set when I get back from vacation/working on the house in Arizona. I'm leaving Friday morning. So, IDEAS??? Remember, these are full comps already.

1. PL 36 rework
1. IC 8 pin if it is a LF356 in it, change to a LF351( gonna try AD825's on Brown Dog adapters.
2. 7.5k ohm's (ROCKWOOD) replace them (they are on the Malco Pins-TRW are ok).
3. 7.5K 2 Watt resistors R1/R2 or R101/R201 Replace,When replacing the LF356 IC with LF351's you will also need to replace the 2.4K/5W dropping resistors (R1 and R2) with 7.5K/5W


4. Original Backplane rework

5. Output Trans. Ideas MJ21195/96

6. Bulk caps to 15,000 uf/160volt ????

7. wiring issues or rewiring?
DC Protection, TURN OFF THUMP repair (OpAmp replacement may cure this) Get rid of twisted pairs on input wiring.

I'm not trying to be rude but can we keep the riff-raff sidetracking to a minimum? It's hard to glean info out of 600 pages of me being a knucklehead and you guys egging me on :smile:
6 WOPL 1000's (2 left), 16 Clair Bros Phase Linear 700 II's, Phase Linear 4000 Preamp, Michael Lim RP6/RP8 custom Turntable, Onkyo P-304 Pre, Epicure 20+, CornScala's, Epicure 3.0 (clones I built)
Good luck with an AD825 on a wired in adapter Perry...
 
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