Vintage Products

Re: HiFi Stereo Amplifier 608

tournedos — Tue, 26 Jul 2011 11:36:05 GMT

Main site -> products -> user & service manuals, but you'll need to upgrade your membership before you can access them.

The adapter part of the schematic is really simple though, I don't think anybody will kill me if I supply just that as an appetizer. The service manual is in Danish anyway

Re: HiFi Stereo Amplifier 608

wolf251066 — Tue, 26 Jul 2011 11:07:03 GMT

Thanks again, I will open it up and take a look. Any pointer where i can find the user & service manuals for this amplifier here ?

Re: HiFi Stereo Amplifier 608

tournedos — Tue, 26 Jul 2011 03:16:50 GMT

I only now realized that we have the user & service manuals for this amplifier on site

I wasn't aware that it actually has a transistorized preamplifier built in (circuit board 915 H 23 B, two per set). Apparently it can be changed between dynamic (2 mV) pickup and crystal (50 mV) pickup levels by replacing some kind of a plugin board, which contains a few resistors and capacitors. Board 915 H 50 is for crystal pickups, do you have those installed now?

The tape input should be the one to use with an external amp, but it may indeed sound different (more modern, or simply duller if you like). The internal preamp uses germanium transistors which probably colour the sound somewhat.

EDIT: the interchangeable equalizer boards should apparently be sticking up in the left rear corner of the chassis. 915H50 for crystal pickups, 915H24 for magnetic pickups. There are also two 470k resistors at the phono input connector, they are short circuited for MM pickups.

If you have the boards for crystal pickups now, they should be easy to modify for MM use if nobody is able to supply the alternative boards for you.

Re: HiFi Stereo Amplifier 608

wolf251066 — Tue, 26 Jul 2011 00:40:57 GMT

Thanks Mika, I tried to go with external RIAA pre amp (NAD PP1) via the Tape input, but the sound was missing the "magic" compared with the "Phono" input ... I guess the one 12AX7 / ECC83 tube in the 6o8 is for the Phono input and bypassing it loses the special sound ?

Now could I try to go with external RIAA pre amp in the Phono input ?

Re: HiFi Stereo Amplifier 608

tournedos — Mon, 25 Jul 2011 03:18:05 GMT

Hi Wolf, hope you haven't yet given up hope for getting an answer!

wolf251066:
I read what I can find on the internet about this amplifier and came to sites that had the technical data for the Type 608 and there was a description of some kind of "adaptor" with which the output sensitivity of the "Gramophone" input can be changed from Magnetc Pickup 2 mV to Crystal Pickup 50 mV - now i am not very good at this technical stuff, but maybe the low volume when listening to records has something to do with that ? But I cannot find that "Adaptor" - is that a separate unit or something inside the amplifier ?

Yes, this level incompatibility must be the issue. I don't know about this "adaptor" myself, but whether it was an internal circuit board or an external box, it must be very hard to find nowadays. Magnetic pickups were rare in those days, so it probably never was a popular option.

But, this is exactly the same problem you have when attaching a modern MM pickup to a line level input. Therefore you can try using any external RIAA preamplifier to solve this.

Re: HiFi Stereo Amplifier 608

Agent00soul — Mon, 25 Jul 2011 02:51:34 GMT

classic:

Martin, please explaine in danish the [ Bandmaster ] receiver, what is the dansih name for that one? or better the type if possible.

Frede

In Sweden the Bandmasters come up for sale fairly frequently, so I suppose that name was used when they were sold in Sweden. Prices are usually in the 60 euro range, unless the condition is near mint.

Re: HiFi Stereo Amplifier 608

wolf251066 — Wed, 13 Jul 2011 02:36:26 GMT

Hello all !

I have a little problem with a very nice sounding B & O type 610 amplifier (Export version of B & O 608 I think) I got from a friend of mine. The problem is, that when I listen to the Phono output with my turntable (MM system) it is very low and i have to turn the volume to 7 or 8 in order to have the music at acceptable levels. Now with the tape out put I only need to have the volume at 3 or 4 to have the same effect ..... I read what I can find on the internet about this amplifier and came to sites that had the technical data for the Type 608 and there was a description of some kind of "adaptor" with which the output sensitivity of the "Gramophone" input can be changed from Magnetc Pickup 2 mV to Crystal Pickup 50 mV - now i am not very good at this technical stuff, but maybe the low volume when listening to records has something to do with that ? But I cannot find that "Adaptor" - is that a separate unit or something inside the amplifier ?
Maybe you have experience with this or know someone who I can ask ?
Thanks and greetings from Austria

Wolf

Re: HiFi Stereo Amplifier 608

ipaul — Sun, 22 Jun 2008 19:14:04 GMT

Another 608 amp sold a week ago via ebay.nl, black front and restaured, for 404,- euro.

Re: HiFi Stereo Amplifier 608

Dillen — Thu, 12 Jun 2008 03:06:17 GMT

B&O used european valves for the majority of their production. I never stumbled upon a 6GV8 valve in any B&O. It's more or less equivalent to ECL85 which is used in vertical deflection circuits so it may have seen use in 50's TV's. I have some servicemanuals of B&O's early TV's so I could look it up but I'm afraid there probably won't be a lot of interest on this forum. I would love to be proved wrong, though.

6GW8 would have been a different story. It's equivalent to ECL86 which was in fact used in several B&O receivers/amplifiers. It can still be found but prices seem to be escalating. Good thing that it's a comparatively long-life valve.

Martin

Re: HiFi Stereo Amplifier 608

Timbo_in_Oz — Wed, 11 Jun 2008 18:59:37 GMT

any information especially a schematic - circuit diagram - would be great!

I have a heap of the 6GV8 valves all NoS.

Timbo

Re: HiFi Stereo Amplifier 608

Dillen — Wed, 12 Sep 2007 01:19:24 GMT

A nice price but I am actually not all that surprised.
The vintage stuff are gaining more and more attention and respect,
especially B&O.
Besides, this particular, somewhat rare, amplifier looks to be in superb condition, MINT cabinet and nice interior, you don't see that too often.

Martin

Re: HiFi Stereo Amplifier 608

ipaul — Tue, 11 Sep 2007 16:21:52 GMT

Just adding this because i've never seen (or paid for mine for that matter !!) what happened here:

http://cgi.ebay.nl/ws/eBayISAPI.dll?ViewItem&rd=1&item=230168430866&ssPageName=STRK:MEWA:IT&ih=013

Value is one thing and quite hard to tell with these things but 865,- euro ???

So far i've seen them ''coming and going'' for roughly 100 to 300 euro, i think with auctions people do make each other crazy sometimes..

What i mean is that one time these go for say 250,- and a month later this happens, i really don't understand this but it gives a nice ''mystic'' feeling about the value of old B&O products :)....

Re: HiFi Stereo Amplifier 608

Dillen — Fri, 07 Sep 2007 04:28:35 GMT

You can read the first couple of posts in this, yours initially, thread.
What's written there goes for both the blue and black versions though
the black version may go slightly higher due to its rarity.
Or simply put it up for sale at Ebay, that will tell you what it's worth.

Martin

Re: HiFi Stereo Amplifier 608

Breeze — Fri, 07 Sep 2007 03:34:44 GMT

The Beolab 608 with the black front (as in the picture of "classic) is the one I own. My question is: what's the value of this amplifier, as I'm intending of selling it.

TIA

Breeze

Re: HiFi Stereo Amplifier 608

classic — Wed, 27 Jun 2007 14:20:32 GMT

Martin,

First of all - you are right. The knobs on the small HiFi Amplifer are NOT original. I have been looking for the original for some time without any luck -- I do hope to find them some day. Actually it is the only thing missing at all on my HiFi Amp - or no I do miss one chassis connector female - like for the BM mic's. One of them are crashed.

Thank for all the pictures of the 'Dirigent', because it is a Dirigent for sure, at least all pictures is exactly like mine. (I think I have two or tree, but all the same as the pictures you have uploaded.

/Frede

a little more from the dealers Handbook:

62/63 --- Dirigent 609

63/64 --- Dirigent K