Akai/Roberts amps?

[Marvel]

I've been looking at old reel to reel recorders, and at some point came across info that the Akai M-8 / Roberts 770X (same units w/different names) use single ended amps for playback throught the built in speakers. From what I remember, they are EL84 amps.

I noticed there are a few on ebay right now, for pretty cheap. Has anyone here ever gotten these and pulled them out of the casee for a stereo amp?

The shipping would be awful, as they weigh over 50 lbs., but it might be worth it if you could get one at a very low price.

Marvel

[WMcD]

This goes back a few decades.

Roberts used a "cross field head(s)." The bias signal was not applied to the main head with the audio signal, but rather via another head which followed the non-coated side of the tape. So the area on the tape was sandwiched between two heads.

It may be that the theory was that a strong bias could be applied without saturating the record head.

The Roberts had excellent performance. Going to 3 3/4 ips was almost indistinguishable from 7 1/2 ips.

My recall is that the Akai was a close copy, but not exactly. I didn't get the impression it was rebranded. Dim recall is that it was held up as an "offshore copy."

In any event, I can't speak to the amp. My guess is that many low power tube amps of that day were single ended. E.g. even a lowly table radio would be single ended.

Now I do understand that people these days find magic to single ended tube amps. No one did back then. Regardless of opinions, there may well be other sources such as mudaine (sp?) electronics of the pre-transistor era.

Gil

[Marvel]

Gil,

Look at these two recorders on ebay. One is the Roberts, the other the Akai. THey may be different inside. I sure wouldn't buy one for the recorder itself, only for the amps.

Marvel

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=67810&item=5708114529&rd=1&ssPageName=WDVW

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=67810&item=5708872992&rd=1&ssPageName=WDVW

[WMcD]

Marvel,

Thanks for the photos. I must say that the Roberts name plate shows it was made in Japan, probably by Akai. Also, the Akai unit looks like a dead ringer. So there WAS some rebranding. My error.

My recall was that the Roberts was made in the USA. You present evidence to the contrary.

My recall from 3.5 decades ago is not that good. I'll also say that perceptions back then may not have been critical, either.

I'm going to say, now, that Akai also made a more elementry version . . . and that is what I saw back in 1969. Just a guess. If it was a dead solid perfect rebranding, we've had noticed it; and commented unfavorably on Roberts.

I'll have to consult a buddy from college. My recall is that he had either a Roberts or an Akai reel to reel which included (gasp) an 8 track recorder which loaded a cartridge on the side.

The Truth is Out There. Unfortunately, it is not necessarily in my brain.

Gil

[Marvel]

Some kinds of truth we don't need to know. Some are Eternal.

Yup, EBay had a Roberts with an 8 track in the side. They both obviously made a lot of different models, and like many companies, some were probably not so hot.

Marvel

[garyeanderson]

I picked up an old Ibanez electric guitar last fall to
play with. I didn't have a lot of money and was looking for an inexpensive tube
amp but seems that any tube amp today has a price that exceeds what I wanted to
pay. I am a total rooky and wanted to limit my out lay in cash. I had the
Roberts 720a and the 990 showed up last week on craigslist. A lot of bad
noise comes out (all of mine) but the guitar with the single humbucker feeding
either or both amps has quite a nice sound if I manage to hit the right notes
without muting the strings that I want to play. The K33 woofers seem to cope
nicely with the 4 watts in the cornwall
style enclosures (did I say it got loud too?). The corn clones were not being
used and I am glad that I found them a purpose. One of the Roberts amps is
going to be coming apart again and I’ll do a bit more cleanup and maybe a few
mods to them. Having fun trying to play and playing with the amps and I guess
with the temps in the single digits the last few days that’s what it’s all
about.

[Speakmeister]

They are great sounding little amps and a bargain for under $200.00. i will look for a link I had on using and setting them up. They can be used in the factory chassis with all the settings in the right position.

[Marvel]

This is certainly a flash from the past. I may have saved some of the info on the amps. I'll try to find it... [:|]

Bruce

[garyeanderson]

They are great sounding little amps and a bargain for under $200.00. i will look for a link I had on using and setting them up. They can be used in the factory chassis with all the settings in the right position.

I have seen quite a few posts that tell you quite a bit about the mods that some do. this one has a number of links

http://lacinato.com/cm/audio/robertsmod

I got the second R to R so that if I messed up I could back track easier. What I have done so far is to just lock the record/play multi switch into the record position with a washer and rewire the 120 volt input (from an ex PC power supply) to have the 3 wire (with ground) using the original 6 pin connector. nothing pretty for sure. This got me to the point where I can use the preamp/amp or I can overdrive it with the "pre out" into the "mic input" and really make some nasty sounds (smile).