Does anybody think that Germanium transistors have a different sound to modern day ones? or am i totally wrong?
I dont usually use cd very often but i do have a couple of older units, so this weekend i got some modern music, strong bass line
and some extension speakers and plugged them into my solid state consoles in turn.
I have 2 consoles that are late 1960s both have germanium transistors and 2 others that are 1975/76 and 1980, listening to them
with the same cd player and speakers i can hear marked difference, the germanium transistors seem to have a more pronounced sound and the bass is deep but kind of odd sounding.
Maybe its just my ears and there is nothing in it, also its probably not the best way to test either.
Anybody have any thoughts?

Too many possible variables here. Let's hope that someone that has been in the semiconductor industry gives you an answer.

Agreed. It is likely you are comparing highly dissimilar designs. There can be a lot of audible differences between transformer coupled audio amplifiers, resistor-capacitor coupled amplifiers and direct coupled amplifiers. So listening to the end product of different designs will not be a good way to identify component affects.

Having said that, one should also consider that germanium devices were among the early semiconductors at a time where getting a good gain-bandwidth product was still tough. The result, if you tried to get too much gain out of an amplifier, could be the loss of high frequency performance.

Curtis Eickerman

Plus, the circuits used with germanium transistors were highly prone to distortion, particularly the difficult odd-harmonic distortion. Some of this was because it was not possible to get matched NPN-PNP pairs in germanium (hard to get NPN in germanium at all).

I try to steer away from the early solid-state stuff. By the mid to late 1960s, quality silicon devices were available and things were much, much better.

-David

oldmusicman........if you collected consoles with tubes, you wouldn't have to worry about this. (Sorry, I just couldn't resist that one....lol). BTW......I bought about 300 cassette tapes at a thrift store last week and there is a Tiffany tape in the bunch! I will keep you posted............GREG

I do have 2 consoles with tubes, i have an RCA HF191 (canadian) and a canadian Electrohome Vogue console, both have been recapped by me and work well.
I guess i just like early solid state consoles a little more, but im on the lookout for a nice Magnavox console and i hoping to find a valved one.
Dont see much magnavox stuff here in canada, have seen very few consoles advertised.

If you are serious about a solid state Magnavox console, I will keep an eye out for one. I go to auctions almost every Saturday, and there are LOTS of console stereos available around here. Magnavox is quite prevelent as there was a music store in this area that sold Magnavox and enjoyed a good reputation. Most times, the auctioneer cannot get a bid on one! I recently was at an auction that had a very nice Zenith Allegro console with all the bells and whistles. I am sure it ended up at the landfill. The main problem with this plan would be shipping. It would kill you.

Update..........I previewed my new Tiffany tape. "Feelings of Forever". I will have to admit, I have certainly heard worse. She is no Patsy Cline, but doesn't try to be. Given the choice between Tiffany and Taylor Swift, I would pick Tiffany. This tape is definitely worth another listen. She reminds me somewhat of Marie Osmond when she was a teenager. And, since I gave you sand about Tiffany, I will admit to being a Marie Osmond fan back when she was about 13. "Paper Roses" is a pretty good album if you run across it. Regards..........GREG

How about a NICE Clairtone (Canadian brand) Project G2?
I bet THAT would fit nicely in your home!

Tougue hanging out yet?

Im sorry RT but that is hideous, it looks like a bad attempt at a nightclub djs mixing desk and 2 bowling balls.

Germanium has technical characteristics which may or may not be well taken into account by a given design.

One of the cleanest audio devices I've ever owned was TEAC A4010 4-track recorder. The output was virtually indistinguishable from the input. It was 100% germanium.

One of the big problems with germanium transistors is that they deteriorate with age, therefore it is quite likely that anything still functional does not match the original specs at this late date. Can't tell you how many dozens of germanium output transistors I have had to replace over the years due to leakage changing the operating characteristics.

It's hard for me to think of any advantage a germanium transistor would have over a silicon transistor in an audio application. But I can sure think of a lot germanium drawbacks. The 4010S had, as I recall, a lot of noise selected germaniums in it. As for its output being indistinguishable from its input, the same could be said for so many line level amplifying devices then and now. My recollection of those germanium TEAC's was that they inserted considerable amounts of hiss into the signal chain. Other than that, they were clean.

Curiously, germanium transistors have a higher leakage than silicon, but undergo less change in leakage percentage-wise as a function of increased temperature.

* * * * *

Though germanium devices can be thought of as simply an early type of transistor, one might ask, other than leakage and bandwidth limitations, what is the number-one shortcoming of germanium? Here's the answer: VERY LOW GAIN. As you know, in a junction transistor, the current-gain or HFE, is the ratio between collector current and base current.

I have bags of silicon transistors (2SC2240, 2SA992) that I use for replacements in low-noise circuits, and these have typical HFE values from 350 to 550. This allows the input impedance of circuits using these transistors to be very high, and frankly it's much easier to design around them. On the other hand, germanium small-signal transistors usually have HFE values around 50-75. This means that the transistor requires about eight times as much bias current as the silicon devices listed above. The implication is obvious: all else being equal, the input impedance of a germanium amplifier stage is likely to be eight times lower than for an equivalent silicon stage using the above transistors.

This makes it much harder to design around them, particularly when coupling to a high-impedance source.

Fred
owner
Classic Audio Repair

Some good information, when did manufacturers stop using germanium transistors, was there any overlap with some built with germanium but others with silicone?

I would say by the mid to late 60's, most hi fi manufacturers had switched over to silicon. But it wasn't total. For instance, the aforementioned TEAC recorders had germaniums in them, and I remember those being sold in stereo shops into the early 70's.

Thankyou.

As I recall, on the Kenwood TK-88, made around 1969, the power amp section used silicon, except for the class AB driver transistor - germanium. At that time, PNP silicon devices were rare and hard to made, and NPN germanium devices were rare and hard to make. Thus, this strange old hybrid. Last time a TK-88 came in for repair at my shop was about 2008. Just about every Elna electrolytic in the machine was bad. Ugh.

Fred
owner
Classic Audio Repair

With germanium, holes were more motile favoring the PNP and with silicon electrons were were more motile favoring the NPN - motile being easier to move for equivalent EMF. Germanium was always leakier and the leakage current increased as the charge carriers diffused at the junction. Diffusion occurred on the shelf (though it was temperature dependent) making fresh transistors no match for fresh tubes.

Just a blurb from someone that has taken a semiconductor physics course.

6.012

I think you have to look at the circuit design. DC bias stabilization was crucial for germanium, hence the use of emitter
resistors that would be bypassed for AC gain. This RC value controls L.F. gain
so the capacitors were chosen to achieve a working relationship between the low and high roll off.

Silicon transistors were more uniform and not as needful of protection against thermal effects (DC bias shift).








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