My New Toy

[VR3]

Soundcraftsmen PCR-800

205 watts x2 at 8 ohms, 300 watts at 4 ohms.

Some of the largest caps and power supply i have seen. I thought the ones in my Adcom were large. Anyways, here is the soon to be (i hope) SDA amp.

[gidrah]

I've got one of those. It sounds great. Interestingly enough though, mine has the ventilation slots where yours appear to be painted on. I've seen this before though.

Good snag.

[Airplay355]

adcom is bad now, didnt u guys know?

[VR3]

Gut Shot

[dave shepard]

Now it'll never work :D :D .

Dave

[amulford]

I'm taking odds on how long it takes him to fry it:D

:p

[disneyjoe7]

Will that be in Minutes, Hours, or Days?





Originally posted by amulford
I'm taking odds on how long it takes him to fry it:D

:p

[Shizelbs]

Weren't we recently bashing a guy on ebay for taking pics of his gear on his driveway?

[disneyjoe7]

Well I feel Sid is trying to make his "Pictures" better.

So I would give him pass on that.



Originally posted by Shizelbs
Weren't we recently bashing a guy on ebay for taking pics of his gear on his driveway?

[Shizelbs]

Good point.

[Airplay355]

what are u gonna do with all that beloved adcom gear of urs?

[VR3]

Originally posted by Vr3MxStyler2k3
Anyways, here is the soon to be (i hope) SDA amp.

[Tour2ma]

The ebay guy was laying vintage, classic speakers on their side on asphault paving...

Congrats, Sid. Look forward to your review.

Now what's this about SDA's???

[VR3]

Hey Tour,
SDA rig in the making so far --

Preamp - Yamaha CX-2
Amp - Soundcraftsmen PCR 800, one or two of them.
CD Player - Unknown
Speakers - Polk Audio SDA 1, A B or C.

I hope to have it complete before the end of the first week of August. (School starts back)

- Insomnia Sid signing out.

[organ]

Wow. Looks like a heavy piece of equipment. If your pre have a second variable pre out you can try bi-amping with the Adcoms on top. That should give the SDA's plenty of power.

Maurice

[danger boy]

Sid,

what are the specs on that bad boy anyways? it looks like the darn thing runs on nitro. true big caps. and some heavy duty wiring inside too. ;)

[VR3]

This amp was well thought out in preserving space, and having a small footprint.
The power supply and caps are huge. It sounds pretty good for the price.

Here is where it wasnt well thought out.....

The Caps and the Power Supply are huge...that is great and all.

There is NO ventilation other than a hole in the rear and a small hole in the front.

Common sense says - Heat rises, dosnt expand outwards. (unless I have been taught wrong) This amp gets so hot, so fast - that after 1 or 2 songs on very well mated pair of speakers; that the truclip lights come on. They don't come on for a the first song or so.

I have two large fans I can put behind it to keep it cool, but this is a major problem. It would be better just to leave the hood off.

For the 90 shipped I paid, I am keeping it - I can find a use, and I hope fans can solve the heating problem.

Right now though, the GFA-545 shames it. Greatly.

[disneyjoe7]

Sid,

What is behind that silver sheet metal in the rear of unit? Is what under a fan? With no holes above the heat sink of the output transistors I would think this had to be a fan.

BTW love you screen name since you explained it.

[VR3]

There is a fan in the back......

But it never turns on unless in extreme situations, like going through extreme volumes, long term playing, or overloads, etc.

Other words, this amp takes about 1.5 seconds to get hot.

There is no ventilation in the case except through the hole in the back where the fan is, and the hole in the front behind the lifted forward faceplate.

Very hot amp.

[disneyjoe7]

It this getting so hot it will shut down? Does the fan came on at all?

Other then that it maybe normal.

[disneyjoe7]

Isn't this the normal listening level for you?

[VR3]

I have no doubts its running hot is normal....lol

My beef is....

It runs so hot, after 2 songs the Truclip lights come on....

The thing sounds AMAZING, HUGE SOUNDSTAGE........

I dunno, when I get some SDA's - I'll mess around with it...

I plan to get some Outlaw Audio Mono Blocks for the SDAs. (If I work alot this summer). That is, if the Soundcraftsmen cant perform. They go pretty cheap on EBay.

Thanks bout the SN..lol (I've had much weirder names btw...lol)

I listen on average of 96-98db. The amp is rated for 205 watts into 8 ohms, and 300 into 4 ohms. Pushing the RTi70 at 96-98db, should NOT be the problem. Especially since the 545 can do it and not even squint.

[HBombToo]

Try some Armour All;)

HBomb

[organ]

Try a replacement fan with an external power supply that you can run continuously. Just place it on the opening outside of the amp so you don't have to take out the internal fan.

Leaving the cover off can be dangerous. If you accidentally touch the leads from the caps even when the amp is off, you're toast. I'm sure one of those caps can hold enough charge to kill a person.

Maurice

[VR3]

Ah, thanks organ.

I will try some external fans

I have some very high powered fans (2 of them), so that should cool it.

Either way, it would make a killer PC rig amp or something. I will find a use for it.

An amp to test stuff on, armor-all, shoot BB's at. You know...:D ;) (A joke BTW)

The amp runs great for about 2 songs, then it goes all to crap......

[VR3]

Another interesting point...

At the time I was listening to Vertical Horizon, track 1 or 2.

And I turn it up to where I usually do, around 96-98db, or atleast with the 545. It sounds great.

It went through the first song fine.

Then the second song comes up, and about half way through it starts to roll into the chorus or whatever. The Truclip lights flash one time......

then it goes on with the song and they flashed more, and more and more....

so I use the CD Player volume control, turn it down 1db. The Truclip lights stopped flashing. The song went forwards (down to probally 94-95db now.

About half way through the 3rd song, the truclip lights started flashing again. This is not even loud, or where I wanted it at the time. Very dissapointed in the performance of the 200 watt beast.

So I figure there was to much heat coming off the Adcoms.

So I relocated it to the very top of the A/V rack. I replayed the songs, and the same exact thing happened.

So then I went forth to unplug it entirely and kept it at rest till I needed it again.

It was like, once it blinked. I could turn it down and it would stop. But then it would blink again later on.

This makes no sense to me, which makes me believe it is a heat issue. Is there something else it could be?

Please dont sit here and make comments are armor all and how dumb I am and all that BS. I just want to know what could be wrong with this amp. I would love to use it at what it can do.

Thanks for all your help.

[Shizelbs]

If heat is the issue, did you give it a chance to cool down after moving the unit?

[Ceruleance]

You might try blasting a fan at it and see if it performs better. make sure the increased dB's are not coming from the fan, though. Are you actually using an SPL meter or guesstimating?

[VR3]

Just going by past measurements on the knob - it has dots, and where I usually tune it to hits around 96-98db. Possibly could have been louder. Not by much.

By the time I moved the wires out and ran new speaker wire to compensate for the length change, it had cooled all the way off.

The fans would be used at higher volumes, which then they wouldnt be able to be heard. I will try it out when I need to. Wrong rig right now.

[phoneisbusy]

Just from looking at the pictures and your description of the ventilation, it looks like the caps and transformer in the front are really restricting the air flow across the heatsink and out the fan.

I know this may offend some people but you may want to consider adding additional ventilation holes for it?

Can you verify that the fan comes on at all? Just wondering if it's defective?

Good luck

Dave

[organ]

I agree with Dave. That power supply and caps need some air. Install one of your fans to replace the stock one. Find someone who can profesionally cut ventilation holes near the front and bottom of the cover. The fan in the back will drag air from the front. That may be the only way to fix your heat problem unless there's a defective part somewhere inside.

Maurice

[danger boy]

i'd say.. take the amp to a machine shop and have them drill some holes or vents in the top of the unit and that will help quite a bit. i'm thinking, fans outside of the unit isnt' going to help with cooling all that much. but if you had it's internal fan working along with some holes drilled in the top of the amp.. air would flow much better. thereby keeping it running cooler.

i can't believe an amp would be built with that kind of power without any vents. it boggles the mind. :eek:

FYI: only take the amp cover. not the amp itself to a machine shop.. you don't want some big hairy gorilla drilling on your cover while it's still on the amp. who knows what could happen there.

[VR3]

That could work --

The fan inside the unit it open to the back, I was planning on firing a fan directly into the unit for cooling.

I can drill holes in the cover :D, drill two holes after the caps and power supply ends, and fire a fan down in them.

Danger,
It boggles my mind to -- makes little sense as to why there isnt more ventilation.

[F1nut]

Sid,

If the original fan isn't keeping the amp cool enough, you have either a problem with it or there is another problem unrelated to the fan, which is what I'm betting on. Before you go drilling holes all over the place take it to a repair shop and have them bench test it.

[gidrah]

Agreed! Don't go drilling holes. If anything, just get some bigger stand-offs for the front or maybe replace the fan.

[madmax]

Originally posted by Vr3MxStyler2k3
There is a fan in the back......

But it never turns on unless in extreme situations, like going through extreme volumes, long term playing, or overloads, etc.

Other words, this amp takes about 1.5 seconds to get hot.

Very hot amp.

This is all wrong MX. My fan turns on with the power and the amp stays cool all the time. Your amp is running in failure mode right now. This is what killed most of these amps originally. There is a wrong size ceramic resistor inside (installed incorrectly by the factory) which needs to be replaced with a different value.

madmax

[disneyjoe7]

Sid,

I being to think something is wrong with this amp. With no music playing can you put your hand over the amp is this too hot to get your hand there?

You say that it will play 2 songs then it sounds crap?

Something has to be wrong. I think an output transistor is leaking. If this is true then I think it is giving DC output without music playing, not good. This will KILL your speaker FAST. Please check this out. An amp should not get too hot just sitting there.

[VR3]

Right now I dont have the funds to mess with it.

This summer when/if things get started. I can venture into an audio shop taking a look. Until then, it will have to just sit and wait for a bit.

But I am seriously thinking about some Outlaw amps for the SDAs. That would rock.

The fan dosnt turn on though...

MAX - can you post a pic? etc, or what needs to be done? :confused:

[madmax]

Well,
I'm sitting here looking at the schematic but it is small and blurry. There is an opto-isolator which appears to be U2 or U3 which feeds a diode bridge (4 diodes) which comes out to a 1/2 watt resistor. I cannot make out the value of it. Not much help here. The 1/2 watt resistor is what was originally in question. I was told you can tell it has gone bad because it turns black from getting too hot. It is a 1/4" x 1/4" x 1" white ceramic thing with a wire coming out of each side. You can at least start by looking for that.
madmax

[disneyjoe7]

A resistor of ""1/4" x 1/4" x 1" white ceramic thing"" is usually a 5 watt power resistor. I question this because you stated a 1/2 watt resistor.







Originally posted by madmax
Well,
I'm sitting here looking at the schematic but it is small and blurry. There is an opto-isolator which appears to be U2 or U3 which feeds a diode bridge (4 diodes) which comes out to a 1/2 watt resistor. I cannot make out the value of it. Not much help here. The 1/2 watt resistor is what was originally in question. I was told you can tell it has gone bad because it turns black from getting too hot. It is a 1/4" x 1/4" x 1" white ceramic thing with a wire coming out of each side. You can at least start by looking for that.
madmax

[madmax]

Yes,
You are correct. .5 or 5, only a factor of 10 off :D
madmax

[disneyjoe7]

Not a problem, getting older myself :eek:

[VR3]

I fixed the fan......

The fan was rubbing the metal casing around it, so I just bent it back out -- it runs now.

However, I dont know if that solved my problem ?

Will know tommorow---

Gidrah, i will test out your cables tommorow as well, sorry for the delay - I have been busy.

It has been on for about a hour now, and is still ice cold. VERY good sign, as it only took seconds to get hot before.

GOOD DEAL. Now I can throw the RTi70 a bone. LOL. Time to go buy some new speakers, BUAHAHHAHA.

[disneyjoe7]

Sid,

You stated this before... >You say that it will play 2 songs then it sounds crap?<<

Is this still true?

BTW glad you fixed that fan.

[VR3]

Well, not that it sounds like crap after 2 songs, its just that it starts to clip so bad, that im so disgusted its crap......

I'm about to put it through a test here in a second as soon as my grandmaw leaves, stay tuned.....

[HBombToo]

and Karnac the great see's blown speakers here in the not so distant future.....:rolleyes:

HBomb

[PolkThug]

"Can you smell the burning of the voice coils Clarice?"
-Hannibal Lectre

[VR3]

I tested the amp out...

Ran for 5 songs perfectly, no clip lights on. Great stuff!

I really like the amps sound when it works right.

Thanks for all of those that helped


Now, back to your regurarly scheduled programs.