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Old 19th February 2009, 11:31 AM   #1
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Default Tube amps from vintage RTR's?

Hi,
I was wondering about the relative quality (fidelity) of the tube amps fitted to Jap tape recorders of the 60's. Eg Sony, Akai, etc.

I have an opportunity to buy a "dead" RTR - ie the tape mechanicals are non-functional but the amp is intact. Is it worth attempting restoration? replacing the passive components?

Doug

PS I'd be transplanting the whole thing onto a new chassis, a la Bottlehead style.
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Old 19th February 2009, 01:43 PM   #2
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I once owned an Akai M7 (or M8?) which was basically a copy of a Roberts. As I remember, the electronics weren't bad if you want a mike or line amp. But remember, they contain equalization circuitry you'll have to deal with. If you can find an Ampex 600 series, they are far superior. The Akai transport is a real dog. It suffers from high flutter by way of a cheesy felt clutch in the supply turntable that cogs.
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Old 19th February 2009, 01:52 PM   #3
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I seem to recall a post of two here about people who have 'salvaged' and rebuilt some R2R amps with good results. If you can get it for a good price,go for it.
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Old 19th February 2009, 06:13 PM   #4
kuroguy is offline kuroguy  Germany
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I built the first tube amp shown at http://buffalo.nas-central.org/index...e=User:Kuroguy using parts I scavenged from an old Sony R2R recorder. I only had to scavenge a chassis and purchase a few capacitors and resistors. Old tube reel to reels are chock full of useful stuff. You may not find the highest qualitty parts, but free is free.
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Old 19th February 2009, 07:03 PM   #5
wboyd is offline wboyd  United States
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I have several of the amps from the AKAI/Roberts RTR's (3 pairs right now). These wonderful little SET amps can be had for cheap on geEdBay and are readily available. You can get them going with just few mods, or tear them down and rebuild...either way they are pretty nice...and the transformers seem to have about 100 taps (not really...but alot of taps). They can yield a wealth of nice parts for building your own little flea power amps....or the beginning of something bigger.

Wayne
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Old 19th February 2009, 07:08 PM   #6
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Quote:
Originally posted by HollowState
I once owned an Akai M7 (or M8?) which was basically a copy of a Roberts.
Akai built the tape decks for Roberts... i have one of these for rebuild, one for spares, and an extra set of amps.

For hifi use the amps need complete reworking, but i figure a fine set of monoblocks can come of them (EF86>EL84). Size of the OPTs will limit bass somewhat.

The highest quality R-R iron i've seen are in the Sony TapeCorder 500. They come with a beefy mains trafo, and a set of nice TamRadio (Tamura) OPTs. Lots of interesting resistors, and a shock mounted double 9 pin mounting. The amp is 6AU6 > 6AQ5, but any combo with 6V6/EL84/6AQ5 could be subbed. The OPTs have a 600 ohm tap which might be a good way to feed SS (sub)woofer amps. The big bonus with these R-R is that they also come with a pair of the Coral holey basket 103As (8 ohm) -- they are usually worth the entry fee, and the amp parts come along for free.

dave

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