Hartke 3500 power amp module - any replacements?

[Dad3353]

If you abandon the project (just in case...)

... Then maybe I'll sell it. Or just enjoy the goodenough (for me) standalone hybrid preamp. Or turn it into a unique yet striking centerpiece / warming tray suitable for special occasions.

Good evening...
If you decide to break up this amp, and if you would post to France, I have an HK 3500 with a shorted-out mains transformer. I'd give a fair price for a working one.
I hope you get it running, but just in case...
Anyone else out there with a busted 3500, same offer...
Have fun, anyway, with your learning curve.
Meanwhile, thanks for reading...
Have a nice day

[jeffjonz]

Anybody know where I can get one of these? It's from a Hartke 7000 S.N.72G1031

[jrfrond]

[ATTACH=CONFIG]17756[/ATTACH][ATTACH=CONFIG]17755[/ATTACH] Anybody know where I can get one of these? It's from a Hartke 7000 S.N.72G1031

Samson will have those as well.

Just FYI- the first-run HA3500 and HA7000 were MOSFET power modules. I was the service manager at Samson from '99-'00 and these things used to self-barbecue, so Inter-M (Korean vendor) came up with a direct-swap bipolar module. If you have a MOSFET module, I wouldn't even try to repair it, but rather upgrade it.

[Enzo]

Maybe you;d remember, John. It has been too long and I forget. Seems to me those new amp module boards come stuffed except for output transistors. SO I'd have to get the board and then buy a set of output transistors to complete. Is that correct? Or am I mis-remembering things?

[diydidi]

Repaired one of these puppies today.
Check the 68ohm resistor on there (R304). Also replace the bias transistor. Check all other transistors of course. Don't forget to check Q311 & Q312. Set bias for 2,5mV between TP301 & 302. Also make sure 1K trimmer biaspot is ok..

[taborinni]

Samson will have those as well.

Just FYI- the first-run HA3500 and HA7000 were MOSFET power modules. I was the service manager at Samson from '99-'00 and these things used to self-barbecue, so Inter-M (Korean vendor) came up with a direct-swap bipolar module. If you have a MOSFET module, I wouldn't even try to repair it, but rather upgrade it.

John, I know this is an old thread however I have the same problem in my Hartke VX3500 combo...bad input cable, ultra high driving resulted in blown power module and 1-2 blown speakers. I just called Samson service at (631)784-2200 and the power module is part number 8-B4001261V210 and the current price is $67.60 I asked about the 16 ohm 10" paper cone drivers and they told me they are being discontinued. The 16 ohm aluminum cone drivers are already discontinued. Just an FYI...

One issue I have had with my amp is whether or not I unplug the power amp module, the preamp section seems to work fine up to using the effects send to another power amp but trying to use direct out (which runs through the equalization processing) outputs a signal with horrible distortion run into a power amp. I'm hoping that the new power amp module will take care of my issues. We'll see.

I wanted to thank you especially as well as the other posters on this thread as it gave me some great clues for troubleshooting, although I am going to have to Google what the light limiter is and exactly how to build it. Sounds like that plus a Variac (which I CAN easily acquire) is a must to prevent a failed smoke test.

[Enzo]

I suspect your DI out is blown, it has nothing to do with the power amp. As an experiment, just disconnect the power amp entirely. Now play through the preamp. I bet that DI send doesn;t sound any different. The drive is just an op amp.

[taborinni]

I suspect your DI out is blown, it has nothing to do with the power amp. As an experiment, just disconnect the power amp entirely. Now play through the preamp. I bet that DI send doesn;t sound any different. The drive is just an op amp.

Thanks for the reply...I tried that a long time ago. The power amp definitely has no output. I'm not saying the DI isn't blown but I know what you suggested didn't make any difference. For the price, even if the power module wasn't blown I will have a spare for when they discontinue everything for this amp. I love it (except for the 4 ohm problem and a single speaker cabinet - I suspect that if I had been able to have an 18" for a subwoofer and cut the 35hz boost to the 4 x 10" speakers I wouldn't have the blown speaker from over-travel. LOL) I will definitely look into what you suggested and try it again simply because I did my initial troubleshooting back in November when I blew everything out.

Again, I REALLY appreciate your response! Daryl

PS - I just looked over the schematic and wanted to add a note...the DI sounds the same, whether the switch is in the post or pre position.

[Enzo]

I don't think you understood me. Earlier you said your DI out was all distorted and

I'm hoping that the new power amp module will take care of my issues

I was asking you to demonstrate to yourself that the power module would have no effect on the DI problem, one can verify that by removing the power module and listening to the DI sounding unchanged. I do believe you that your power module is blown, and replacing it is a good idea, but it won;t help the DI. What I suggested was ONLY a method to examine the effect on the DI, it had nothing to do with power module repair.


Your DI sounds the same either switch way because in all likelihood, it is the DI drive itself that is blown. I suspect the 5532 IC106.

[taborinni]

I don't think you understood me. Earlier you said your DI out was all distorted and



I was asking you to demonstrate to yourself that the power module would have no effect on the DI problem, one can verify that by removing the power module and listening to the DI sounding unchanged. I do believe you that your power module is blown, and replacing it is a good idea, but it won;t help the DI. What I suggested was ONLY a method to examine the effect on the DI, it had nothing to do with power module repair.


Your DI sounds the same either switch way because in all likelihood, it is the DI drive itself that is blown. I suspect the 5532 IC106.

Ahhhh, you're right, I did misundertake you. LOL The main reason I had even tried the DI was to run it into another Samson power amp I have (until I could get the "rest" of my Hartke working.) and *hope* I could still utilize my equalization, etc. I wonder if it would be equitable to acquire that IC and try it out? I don't have the experience to actually test that. I know to test the power transistors I need to unsolder them and I generally know how to test resistors, etc but IC's are beyond my meager knowledge. As Grand Funk Railroad said at the Atlanta Pop Festival when they asked people to move back, they didn't want to and the band said "Comeon man, we wanna, we wanna play!" In my case, "me" wanna play! hehehe

Thanks again for helping me!

[Enzo]

A 5532 IC is maybe a dollar. I just looked at Mouser, 5532 is exactly $1. Since you report that the distortion is the same set for pre or post, then I have to think it is indeed that drive IC, because the pre and post signals come from different places in the amp. So it is of course possibly not at fault, but I would have it swapped out by now in my shop.

I don't know where you are, but most amp repair shops will have a 5532 in their drawer. Or other store that has audio parts.

[taborinni]

I'm about an hour north of Dallas. I will try that IC right away as just having my EQ back would be great until I can fix/replace the power module. I know I could replace the power transistors and the driver transistors but my preference is that I have a new working module and replace the other parts at my leisure. LOL

You really rock my friend and I appreciate your assistance more than you know!

[taborinni]

Oh, any ideas as to what would toas that particular IC?

[Enzo]

The outside world.

A fact of life, electronics that fail find the failure more often than not in parts that interface the outside world. In other words input and output components as opposed to some part right in the middle. That chip connects directly to the DI connector with only a couple 100uf 50v caps to protect it.

Of course there can always be an exception. For that matter it is entirely possible those two caps are bad instead of the IC.