Roberts (Akai) 1630 R2R - First R2R, need advice

[Slump]

Forewarning: Long post
I want to start off by saying that my electronic experience is novice. I have a 120V soldering iron (I know I should get more tips), desolder bulb, and a multi-meter. I've read the textbook "Electronics for Musicians" and have started making my first pre-amp from the schematics in the book and a simple cigar-box spring reverb.

Lately i've been "experimenting" with cassette, but more as an outboard effect (tape saturation) and wanted to expand my experimentation a bit; anyways, I went to this flea market with some friends and I checked every cassette player to see if it had 3 heads (to try and make a tape delay), but instead, found a Roberts 1630 for dirt cheap ($15) and it powered on so I decided to nab it. (never did find a 3-head cassette deck)

Front:

Back:


Upon taking it home I immediately put a signal through it to see what would happen and how it would sound. It says "pre-amp outputs" so I figured that the phono inputs would work best with a low level signal; I hooked up a turntable (Numark TT200) into the phono inputs and played a record. The 1630 has 2 speakers on both sides of the unit; there was no output/audio. I then connected the RCA "pre-amp output" into my shitty audio interface and monitored the signal in cubase5. No output again, but whenever I would twiddle with the volume knobs a scratching noise would occur in proportion to the volume (I mean to say that the higher the volume knob the louder the noise)
Here's the noise:
Roberts 1630 Output by Slumpy on SoundCloud - Create, record and share your sounds for free

The next thing I did was open up the back and, to my pleasent surprise, I found a bunch of tubes. The machine came with no manual, but google turned up the fact that it's from the late '60's and was distributed by a company based in LA (Roberts) but was made by Akai.
It has 5 tubes:
x1 NEC-49 (Far Left; google turned up nothing on this tube, have no idea what it is)
x2 6BM8/ECl82 (2 bigger tubes upfront; brand RCA)
x2 12AX7/ECC83 (2 smaller tubes in the back [the far right RCA tube is hiding the far right 12AX7])
Note: The visible 12AX7 is a mullard brand, the hidden one is a brand that I can't identify due to the angle of the tube, it has green typeface though.



So it seems like I could make some cool tube saturation outboard effects with some of these old tubes if they're still good. I don't know if this helps in anyway determining whether or not they're good, but here is a picture of their glow after the 1630 had been on for awhile.

Lights Off:

Lights On:


Then I took off the plate covering the electrical guts of the 1630 and saw this mess.



I'd love to be able to restore this R2R so that it works, the quality isn't so worry-some to me because I kind of want it to have bad wow and flutter and the like because i'll be using the R2R as an outboard effect rather than a 4 track recording workstation. I know the first step in trying to fix it is to find the schematic so I can make sense of this "pre-PCB" (aka mind=blown) mess of components, but I can't find one anywhere.

I guess my question is this: do you guys think the money I'd need to invest to get the 1630 working is a lot (price range: under $50) or am I better off spending the same or less money on gutting it and making other effects out of the parts and putting the "shell" on a shelf.

PS: If the pictures sprinkled throughout the post don't work, here are the links.

Roberts 1630 Front:
DSCN1692.JPG - Bilder und Fotos kostenlos auf ImageBanana hochladen
Roberts 1630 Back:
DSCN1704.JPG - Bilder und Fotos kostenlos auf ImageBanana hochladen
Tubes:
DSCN1702.JPG - Bilder und Fotos kostenlos auf ImageBanana hochladen
Tube Glow:
DSCN1705.JPG - Bilder und Fotos kostenlos auf ImageBanana hochladen
DSCN1710.JPG - Bilder und Fotos kostenlos auf ImageBanana hochladen
Guts:
DSCN1701.JPG - Bilder und Fotos kostenlos auf ImageBanana hochladen

[Bill@WelcomeHome]

well, if you knew wiring and could replace the parts yourself, the tubes would cost more than $50. It seems as if this is an integrated amplifier type device with included tape deck and speakers. If so, many of the tubes are probably a part of the amplifier circuitry. One is probably a rectifier for the power supply. If all you want is the tape deck to work, you'd only need to replace the power supply tubes and any tubes that applied to the tape deck. But you are right, the amp itself might be capable of some really cool sounds, accessible via an aux or tape input.

I'm a plumber when t comes to this stuff... with proper instruction I can solder in the pieces. What you describe I would probably send out to someone else, someone who knows what he is doing. But it never hurts to do a little experimenting on your own if you have the time. Just watch out, because tube devices often run on high voltages and the capacitors can store a high charge. It is very possible to shock yourself badly even when the unit is turned off and unplugged.

[audiotech]

I would like to help you here, but for the life of me I can't make out any detail in your photographs. I was trying to see what the jacks were labeled on the first picture and really can't. I have a full track Roberts that's similar to yours but I just can't compare them looking at the photos.

Better well lit pictures would help out a lot.

Dennis

[mjrippe]

That "NEC 49" is probably a 6X4 if I remember correctly. That would be the rectifier tube. The 6BM8s are output tubes for the amplified speakers, 12AX7s are preamp tubes.

Have you tried different inputs and outputs? Or running a line level signal in? Headphone out? Also try running some tape, it may only pass signal with tape on it. Clean the entire tape path first though!