Blown out pre amps where can I repair - Tascam FW-1884 Firewire Audio / Midi Interface Sound Card

I assume your turntable was connected to the record deck input on your amp when you lost volume from it. Then you tried other connections marked tape or CD?
As you have tried different cartridges with no response we can assume the piece of equipment that has failed is not your record deck. Instead it is your amp. The problem you are experiencing is that the pre-amp inside your amp has failed. This pre-amp is connected only to the record deck input of the amp. The other connections don't have this pre-amp which is called a magnetic cartridge pre-amp. So connecting to them will just give you the signal only from the deck, which as you say you can hear, thus proving the cartridge is working, but will be low in volume.

If you are any good at electronic repair it will be easy to fix this pre-amp. You can find it by following the internal connections from the record deck socket back to a circuit board. The chances are this will lead to an IC that does the work. Get the IC number and search the web for it, before removing it.
Alternative you can take it to a service centre for repair if you have no experience of electronic repair.
Another option is to search the web for a magnetic cartridge pre-amp. These are sold separately as many Audio amps don't have them fitted, seeing not many people have record decks. This can be connected between the deck and one of those other inputs (don't use the record deck one). The cost of one of these might work out cheaper than repair at a service centre. The repair by yourself will of course be cheaper, unless the IC is hard to find or specialised. But a search of the web for the IC number will show how cheap it is anyway. However if the IC is expensive that will also make repair by a service centre expensive too. So you can save the expense of the repair by going for a new pre-amp.

Here is your schematic:

http://elektrotanya.com/peavey_pv-8.5c_sch.pdf/download.html

Scroll down to "get manual" and click to download. IGNORE other "download links" n the web page.

The amp has likely got a shorted output section or a shorted component in the power supply. Unfrtunately the previous is the most likely AND EXPENSIVE to repair.

One of your five amplifiers has blown its output transistors. Unfortuately, with SR18s, many components down the line from the outputs get fried as well, and (in my experience, anyway) it usually takes hours to track down all the problems. You can still use the unit as a preamp/tuner/surround processor by taking signal out at the pre-out jacks (you have to remove the five jumpers), and feeding it into external power amps, but repairs to the SR18's amp are probably going to be costly and complex. Sorry about the crummy news - hopefully I'm wrong!

If you are not looking for a warranty repair, any shop that handles high end audio repairs should be able to resolve this for you. Before you ship off the pre-amp, verify that it is, in fact, the pre-amp that is defective. The initial stage of the power amp can cause this as well. Try hooking up another pre-amp instead to verify the problem location.

Keep us posted,
Dan

To my knowledge this is no switchable pre-amp on this unit. Just connect to your own phono pre-amp and you should be ok.

- OPTiC
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Without hearing the distortion, it will be difficult to state with any confidence where in the amp the problem exists. That being said, the most common problem is with the preamp section. Many of these use 4558 chips as the pre-amp section. If hte chip is blown, the sound may still be heard, but it will be distorted. This is easily seen on a scope. The chips can be purchsed in bulk for les than $1, so the parts cost for the repair should be low.
Dan

Yes, you'll need to purchase a PHONO PRE-AMP, and then connect the turntable to the pre-amp, and the pre-amp to the LINE INPUT of your receiver.


- OPTiC
Turntable Repair Expert
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Try only A speakers.