| phrarod |
I have some blown diodes in the power supply and I would like to have schematic to check everything.
Also in your experience when a FED blows is it an indication of other problems?
Is it worth it to try and upgrade anything in this amp while its on the bench? |
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| Perry Babin |
According to Soundstream tech-support, the schematic is not available.
Sometimes the FED16BT rectifier diodes fail and there is no other damage. Sometimes they short and cause the failure of the PS FETs. Sometimes the outputs fail and cause the rectifiers to fail. |
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| phrarod |
| I talked to a tech up north who used to work for Soundstream. He said the same thing. I'm replacing the FED with a higher rating that the tech recommended and also upgrading the output transistors as they're a combo of two different types. I guess mine was build as they were transitioning to new parts. Hopefully this will fix it. Since its so old I also replaced the caps. |
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| Perry Babin |
What were the replacement parts he recommended?
I don't know of any rectifiers that can handle more than 16 amps in the to-220 package.
I've seen the TIP142T and TIP147T in some of the amps. They have a slightly (depending on the datasheet you reference) higher current rating.
If that's what he recommended, make sure that you get the ones in the TO-220 case. The TIP142, TIP147, TIP142TU and the TIP147TU are in a TO-3P case. |
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| phrarod |
| I think they are slightly higher. He said he always upgrades amps that come in with these so I imagine they'll fit. I'll let you know when they arrive next week. |
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| justonemoreamp |
The MC-245 uses TIP142 and 147 in the TO-218 case. They can be replaced with the later case style TO-220 T versions. Same device, smaller footprint package, used in Rubicon series amps A couple years back.
I know of NO replacement for the FED diode because of its "special polarity consideration", and its rather difficult to find BUT there is a fella on E-bay by the name of Jaime that sells SoundStream parts (all original) He worked for SoundStream for 10 years. Look for JandRelectronics on E-bay. The FED16BT is special the diodes do not form either common cathode or anode configuration like all the other standard packages do. Check the diode directions on it case package < its special > LINKY: http://cgi.ebay.com/ws/eBayISAPI.dl...s_promot_widget
He also can repair the unit to original specs, along with sell you all the correct parts to complete the job yourself. He might even be able to dig up a print somewhere, since Soundstream seems to have lost them over the years.
He is a one stop shop for ALL Vintage SoundStream parts
Hope this help, and good luck:) |
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| Perry Babin |
The FEP16BTD has the same configuration as the original soundstream parts. It has the same specs so it wouldn't be an upgrade.
I didn't know that SS ever used TO-218 parts. Coustic switched from the TIP142/147 to the MJH110xx series transistors. I think they used the MJH11017and MJH11018. They were a direct replacement for the coustic amps. I don't know if they could be used in the SS amps.
http://www.onsemi.com/pub/Collateral/MJH11017-D.PDF
J&R electronics is definitely a good place to get SS parts. I've recieved top-notch service every time I've ordered from him. |
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| justonemoreamp |
Evening guy's, sorry had to work on a few computers. So I was away for a bit.
SoundStream used three different configuration dual diodes. The FEP, the FEN, and the FED.
The FEP is common cathode, the FEN is common anode, the FED is anode , cathode, cathode.
Yeah Jaime is the best:) You gotta love the guy. He is the fastest, and nicest supplier I ever had.
I agree you can use more modern outputs like you linked to, But TIP142's and 147's are plentiful everywhere. The T version is used only in the Rubicon series though it could be used in the MC series as well. Jaime has the T series, just not listed on E-bay.
I just repaired two MC-140's last week and TIP 142' and 147's were under the card, so I replaced them with the same.
hope this helps:)
my pic of the FED dual diode would not upload so sorry guys, I guess its too big:( |
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| phrarod |
Thanks for all the great posts! Yup all the parts are coming from Jaime. I'm replacing all the output transistors going from 101 to 102 and 106 to 107. The amp had a couple 107s in it so it was mismatched. I'm the original owner so it came this way from the factory. Jaime said they switched to the 102/107 combo later.
I don't know the part # of the dual diodes. I'll upload that when I get them.
I did find a burned resistor in one of the channel's high pass filter network. It didn't destroy the resistor just changed its resistance by about 1 Ohm. Everything else look visually ok. The only strange thing is I cannot get continuity between common ground and the neg pad for the 2200uF cap that is closest to the sub speaker connections. Before with the blown diode there was continuity between the +/- of that caps pads.
As long as I'm deep into this board are there any mods that would improve the sound of this amp? I'd love to figure out how to put tube minatures in somewhere to get a nice tubey sound. |
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| justonemoreamp |
My memory of those MC series amps is that they left little room for upgrades. Perhaps you might change out the input op-amps with AD or BB op-amps. I just did this today for a PG amp and it really changed the way the amp sound <for the better>:)
With the age of your amp I would possibly exchange all the outputs and see if you get a lower DC offset at the output, and don't be afraid to replace the power capacitors on the 12 volt side and the main rail for each channel.
There just isn't much else you might do, unless you find some more leaky or defective components.
The TIP 102 & 107 upgrade wont give you anything but the fact your using the highest grade of that series of transistor, But this couldn't hurt.
How many output pairs per channel ? :) |
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| phrarod |
Parts came in yesterday: FED16s where the slightly higher rated ones he was talking about.
I thoroughly cleaned the board and carefully put in the parts. Brought it up slowly with a variac because I read it doesn't have a regulated ps and the caps are new. Works!! No fuses blew and the one channel I tried played fine.
I replaced all the caps at the beginning hoping that was it. I couldn't find Nichicon in the 1000uF 50V radial package. All I could get was Xircon which I know is ****. I did get a pair of TCI ones in the order but I don't know if these are any better. What does that pair of caps control? Should I try to get better caps or try to squeeze larger ones in there? Or no sonic benefit?
It has a 2 pairs of 102/107 per channel. So 8 pairs total.
I asked about changing the opamps but the tech said I might get into timing issues. There's 4 opamps on the underside of the board. Are those the ones you're talking about? T223TIPs.
There's 6 MTP25N06 RB2 on the power supply.
I'd love to do something. I'm impressed on the components they used. All high quality.
There's still something funky with the one hi-pass filter where I found a burned resistor but I use the head decks controls for that anyway. |
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| phrarod |
I did find out that the 1000uF 50V do supply the 4 channels. I can either get a audio grade cap in 1000uF 50V which is the same size as the 2200uF 50V or I could just put in the 2200uF 50V.
Would any of this make any sonic difference?
The amp is sounding rather thin and brittle. It could be the new Sony head unit which I don't care for... CDX 5715R
I know better ps caps in home audio result in a quieter less distortion presentation. Don't know if its overkill here. |
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| justonemoreamp |
With the age of your amp I would upgrade the power supply caps just for principal that they don't last forever, and any extra energy storage would be only helpful, and the extra filtering is just a plus also.
As for op-amps the numbers you posted look like date codes not ID numbers look again to see all the printing on the the little 8 pin square blocks, Please?
I think they used TLO62 or72 or82 op-amps <all the same family just different grades> There all lots of better op-amps then those, as for timing issues, well I don't understand the reference with regard to audio but maybe I'm missing something :xeye: |
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| phrarod |
I already put new ps caps in. Just fussing with getting better 1000uF 50v.
I was looking at the wrong place for the opamps. I have three 6 leg on the four channels 3067 F1D and one 8 leg on sub TL07CP |
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| phrarod |
| Ooops. Make that 5 of the 6 legged surface mounts. |
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| justonemoreamp |
Jaime has those dual transistors <the 3067> those are the diff input to the amp channel. Ampslab has them also, but higher cost. TLO72CP is the op-amp number, Easy to find and a better grade part would be TLO82.:)
If after replacing the outputs you still have a larger than expected DC offset at the output, then try and replace the 3067 dual transistor. They get damaged by being overdriven, and cause DC offset on the output to be higher than normal. |
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| phrarod |
| How can I measure DC offset with just a DMM? |
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| phrarod |
OK. I measured the speaker output with my DMM. Once channel is below 20mV However the other three are high 42.2/45.6/46.3 Jaime said below 100mV is ok.
He thinks I'm just throwing parts at it because I don't have a scope to measure all the proper specs. He also said if I was going to a 082 I should go up to a OP275 as that would be better. |
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| justonemoreamp |
Follow Jaime,
He would know better than the rest of us. I don't care for a 100 MV DC offset. But thats just me :) . |
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| phrarod |
| I'm with you. What I read was below 20mV. One channel is fine the rest are high. How can I reduce it? |
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| justonemoreamp |
I have found that the outputs get leaky with being over driven, and the dual transistor up front can also be a source of offset. It can be one or many of the semi's, including diodes. Its time consuming work to find the source, but it can be resolved if you have time and parts.
You can wire in a 10 or 20K pot across the + - 15 volts and connect the wiper to the input just behind the input cap, and adjust the offset out of you channel this way. But it does not resolve leaky semi's. It just resolves offset.
PPI had this setup for years without issue. Whenever I would get one in I would try and reset the offset as small as possible without causing issue with distortion and power output, and bias alignment.:) |
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| phrarod |
| I'm a big fan of doing it right. My limited equipment and knowledge prevent me going further in tracking down the problematic parts. |
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| phrarod |
| Wait a minute. These do have wipers. I thought they're just input line level. I still have no schematic but here's a photo. |
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| justonemoreamp |
They are your input gains, you would have to add the pots I was talking about to gain DC offset adjustment. But pots are cheap and it would counter your offset issues on the cheap. Sorry about any confusion I might have caused you on my post:)
Clean looking amp by the way :) |
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| phrarod |
I realized after I posted they were indeed the input gains. I really cleaned the board although it wasn't that dirty. I mainly cleaned off the ton of flux. I'll do the pot trick. Found some 2200uF 50V caps that I can squeeze in place of the 1000uF 50V caps for the 4 channels and then unless theres really something that you think will be a day and night difference in SQ I'll just button and back up and put back in the car.
I'm thinking the way to improve the SQ is going to be with a different HU. Know anyone who could look at the schematic of a Sony CDX R5715X and tell me how to improve the sound? |
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| phrarod |
I did an A/B between the 245 and a small tri-path I built for the home that runs on 12v. The tri-path (15W) had better body to the presentation. The 245 is still sounding "thin". I've been blaming all of it on the head unit so I was surprised the little tri-amp sounded better with less distortion.
Does this point to anything in particular in the 245 to you? |
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| justonemoreamp |
| I would need to understand your description of "thin" to be able to better guide you at this point. |
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| phrarod |
No warmth or body to the sound. More upper register. Rather brittle, possibly with a high frequency tone over riding any warmth of midrange. Exceedingly bright.
This is on the test bench using single drivers. The exactly reminiscent of the sound is the same in the car. When I used the tri-path the sound had more body and warmth. More accurate representation from low midrange up through the highs.
The high pass filters actually make it worse. This is just on the front 4 channels (actually two as I have them bridged).
I've been blaming it on the HU. When the tri-path was in circuit it wasn't as bad. |
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| justonemoreamp |
Humm, Sounds like one or both of those channels are out off spec. Do you have the means to check the capacitors I.E. a LCR meter ?
Whats the offset on those channels ? Is there any DC on the RCA input ?
How big is the power supply your using ? I ask because the Tripath is 90% efficient and the AB Soundstream is about 50% efficient.
Other than that you are comparing two completely different types of amp against one another. Perhaps thats why your hearing a difference. I would need to run some more tests to try and characterize the sonic issue your amp has. Run a frequency bandwidth scan, Distortion check, response flatness. maybe pass a few square waves from 7 K on up to see whats up, and check for crossover distortion.
Many of these old school amps had Crossover notch distortion issues and that might be what your hearing:)
Just pass some sine waves and visualize them on a O scope, you can't miss the notch's at the crossover point if they are there, Hope this helps |
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| phrarod |
I only have a DMM. I'd have to send the amp to you for all these rest. All the ps caps have been replaced. I'll try to see if there's any DC on the rca's. I have the DC offset in an earlier post. Basically 3 of 4 are 46mA and one channel is <20mA.
I guess its probably a form of distortion. Not enough to corrupt the sound completely. Just enough that I can't EQ it out with the HU.
No DC on the RCA inputs |
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| Perry Babin |
| If your multimeter is a 'true RMS' meter and has a bandwidth of ~20Khz, you could do a sweep and check the frequency response. |
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| phrarod |
| Perry. Any link on how to do that? My DMM is suppose to be true RMS |
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| Perry Babin |
You need to determine if your meter has enough bandwidth. The owner's manual should tell you.
You will need to check the response of your audio source to be sure it has a flat response. Set all equalizers, the controls and the loudness to off (center position for tone and equalizer controls).
Run the sweep and connect your meter to the RCA outputs. Set the level for ~1 volt. Restart the sweep and watch the meter. It should stay near 1v. If it varies by more than ~0.12v, there may be some sort of equalization in use and you need to remove it or take it into account when checking the amp.
When driving the signal into the amp, you want to do so at a relatively low level. 1-2 volts is enough to get reliable readings. If you do it near full power, you may damage the amp. Some amps will self destruct when driven to full power with a 20kHz sine wave.
Allow the test tone to sweep while getting the output level right. When you have it at the level you want, restart the sweep and watch the meter. Again, you don't want to see more than ~0.12v variation. That's ~1dB.
This is the link to the sweep. There's a limit to the number of downloads so it would be nice if others would allow you to get it first. When you have it, let others know you have it to allow the rest of those who want it to download it. If the downloads max out before you get it, email me and I'll post it again and send you the link via email.
Distribute the sweep freely.
http://s01.11send.com/?01070305842595951544 |
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| phrarod |
Thanks Perry. I have to concentrate on this exercise as I've never done it before. Sure am anxious to learn though.
The link worked although the download link didn't work. |
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| phrarod |
Got it!
Ok. Later tonight I'll give it a go. Thanks so much. I'll let you know. I'll burn it to CD and put it in the HU. |
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| Perry Babin |
If someone wants to host the file on their server, get it now. I'll remove it later tonight to prevent excessive bandwidth usage.
phrarod:
Remember to start with the volume at the minimum. |
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| phrarod |
| I looked at my meter. Its auto range - Extech. Hopefully it will do the job. I'll see if my serve can handle hosting it. How much traffic do you think it will get? |
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| Perry Babin |
| I don't know how much it will get downloaded. The server I have it on has a lot of large graphics files so it uses a lot of bandwidth on its own. |
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| Here-I-Come |
First I will say Hi and this is a great site full of info. New here, but not to Car Audio.
Hate to dig up a old post but,
I was just wonder is/was/will there any sonic improvements for change in input op-amps to the TL082 or the OP275 on MC245 and upgrading the power suppply Caps on the MC245 or any of the older MC's or D's Soundstream amps.
The reason I ask is I have own 2 MC245, 2 D100II, a MC140x, and a D200 (for first one, not the series II). I had a MC140 but I just sold it and now I want it back all ready.
Thanks for all your help in advance. |
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| marko |
| i owned an mc245 and was a sweet little sounding amp, i just won a d100 on ebay so can't wait to have a play with that and see how it compares with my ref300's :) |
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| phrarod |
| Its hard to say because I was using a crappy HU at the time. Now that I upgraded to a top Alpine unit the amps sounds better than it ever had. The caps in my mind are a must simply because electrolytics dry out. Not sure I heard a difference with the op-amps but again, I had the wrong HU to judge. They're cheap and easy to replace. |
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| Here-I-Come |
| quote: | Originally posted by phrarod
Its hard to say because I was using a crappy HU at the time. Now that I upgraded to a top Alpine unit the amps sounds better than it ever had. The caps in my mind are a must simply because electrolytics dry out. Not sure I heard a difference with the op-amps but again, I had the wrong HU to judge. They're cheap and easy to replace. |
Takes for the reply.
Where can I buy the Op-amps, and which ones did you go with the 082's or the OP275's.
Once more thanks for all your input. |
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| phrarod |
| Check e-bay and look for a Northern California seller who has parts for Soundstream amps. He used to work for Soundstream and has all the parts. Don't remember his name right now but he's easy to find on eBay. |
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