Any info/knowledge about this unique german tube guitar amp?

[devilsindetails]

That's a pretty cool looking amp.

Does it work?

Are those cap cans original?

Gonna bring it up slowly with an isolated variable power supply after I make sure there are no physical signs of obvious distress. Will keep you posted.

Leon

[devilsindetails]

That WIMA in pic 36 looks bigger than that nine pinner!

Yes...that appears to be the reverb section or (german) "vibrator" section...not sure how that circuit is implemented or for that matter how it works....I'm going to post pics of that tube to see if anyone knows what type it is...no silkscreen identifying marks...it is a TFK tube though...

[overtone]

Nice guts!

The company who made that amp is local to me - in the next town right next to Frankfurt. I can PM you their telephone number if you like, because they still have a repair service!

The gut shots are typical of many fifties German amps, in the choice of components, tag board and layout.
Some experts here in Germany are very rude about those early brown Wimas, but I have never tested them myself. The other light colored caps are Hydra Werk which was in Berlin.
The text on the transformer basically means "customer special winding" and Block is a transformer company that is still producing in Verden, which is near Hamburg.

Looking forward to hear how she powers up,
best, tony

[devilsindetails]

Nice guts!

The company who made that amp is local to me - in the next town right next to Frankfurt. I can PM you their telephone number if you like, because they still have a repair service!

The gut shots are typical of many fifties German amps, in the choice of components, tag board and layout.
Some experts here in Germany are very rude about those early brown Wimas, but I have never tested them myself. The other light colored caps are Hydra Werk which was in Berlin.
The text on the transformer basically means "customer special winding" and Block is a transformer company that is still producing in Verden, which is near Hamburg.

Looking forward to hear how she powers up,
best, tony

Thanks Tony...yes a phone number would be great! So what is the actual manufacturers name?

Leon

[overtone]

You were right with K.A.Schmitt on the brass plate.

PM sent, they do call-out service!


The look of the amp really reminds me of the early Dynacords which are well loved by Harp players.

[devilsindetails]

You were right with K.A.Schmitt on the brass plate.

PM sent, they do call-out service!


The look of the amp really reminds me of the early Dynacords which are well loved by Harp players.

Out-Call service? Wow that would cost a pretty penny with travel here to Canada

[devilsindetails]

Well I finally fired up the K.A. Scmitt Amp but despite the tubes all lighting up nicely...not as much as a hum from the speakers....

Tried all the inputs: 1Xmicrophone 3 X instrument but nada...nothing...

Will check all the voltages...next but I have a bad feeling the OT is blown...

[tubeswell]

That WIMA in pic 36 looks bigger than that nine pinner!

Yes...that appears to be the reverb section or (german) "vibrator" section...not sure how that circuit is implemented or for that matter how it works....I'm going to post pics of that tube to see if anyone knows what type it is...no silkscreen identifying marks...it is a TFK tube though...

Identify which bits of the circuit are going to which socket pins. That should narrow it down a bit. If that tube is providing the entire reverb send and recovery it could be a dual triode or a triode/tetrode or similar.

Well I finally fired up the K.A. Scmitt Amp but despite the tubes all lighting up nicely...not as much as a hum from the speakers....

Tried all the inputs: 1Xmicrophone 3 X instrument but nada...nothing...

Will check all the voltages...next but I have a bad feeling the OT is blown...

Are the speaker coils open?

Also you could check for VAC across the OT windings by unplugging all the tubes and unhooking the OT primaries and secondaries and hooking the OT secondary up to the 6VAC PT winding and (carefully) measuring the (high) VAC across the primary - being careful not to let any of the windings short out to each other or to the chassis or anything else for that matter.

If the OT is functional and you end up with VAC across the OT primary, make a note of the exact VAC being supplied to the secondary and the exact VAC you're getting from each side of the primary, and this will give the Pr:Sec VAC ratio (and hence the impedance ratio can be calculated) as well as telling you whether the OT is alright (if the VAC on each side of the primary is the same). If that's okay then you can look for other problems.

[overtone]

I think that tube is a TFK EF804 or EF806.

Tomorrow is a public holiday in Germany. If I get time later in the week I'll see if anyone at the shop remembers this amp.

Best, tony

[devilsindetails]

That WIMA in pic 36 looks bigger than that nine pinner!

Yes...that appears to be the reverb section or (german) "vibrator" section...not sure how that circuit is implemented or for that matter how it works....I'm going to post pics of that tube to see if anyone knows what type it is...no silkscreen identifying marks...it is a TFK tube though...

Identify which bits of the circuit are going to which socket pins. That should narrow it down a bit. If that tube is providing the entire reverb send and recovery it could be a dual triode or a triode/tetrode or similar.

Well I finally fired up the K.A. Scmitt Amp but despite the tubes all lighting up nicely...not as much as a hum from the speakers....

Tried all the inputs: 1Xmicrophone 3 X instrument but nada...nothing...

Will check all the voltages...next but I have a bad feeling the OT is blown...

Are the speaker coils open?

Also you could check for VAC across the OT windings by unplugging all the tubes and unhooking the OT primaries and secondaries and hooking the OT secondary up to the 6VAC PT winding and (carefully) measuring the (high) VAC across the primary - being careful not to let any of the windings short out to each other or to the chassis or anything else for that matter.

If the OT is functional and you end up with VAC across the OT primary, make a note of the exact VAC being supplied to the secondary and the exact VAC you're getting from each side of the primary, and this will give the Pr:Sec VAC ratio (and hence the impedance ratio can be calculated) as well as telling you whether the OT is alright (if the VAC on each side of the primary is the same). If that's okay then you can look for other problems.

Nope...I checked speaker continuity and DCR off the bat...the drivers check out ok.

Yes..I'll check the voltages and pin-outs of the mystery tube.

Thanks for the help...Leon

[devilsindetails]

I think that tube is a TFK EF804 or EF806.

Tomorrow is a public holiday in Germany. If I get time later in the week I'll see if anyone at the shop remembers this amp.

Best, tony

Hi Tony...Nope not an EF804...the ???? tube has a shorter bottle and the top of the plate structure is quite different. There is a TFK EF804 in the rest of the tube complement so I have a known example to compare to.

I'll look at the EF806 on-line and see if that looks similar.

Thanks for doing this for me. Much appreciated!

Leon

[overtone]

found this on a German site.
Already gooped!
This is supposed to be from 1962, but may be of help.

[devilsindetails]

Thanks Tony....getting closer...too bad about the goop on the schematic maybe the fellows at K.A.Scmitt will have a complete version....

Much appreciated....Leon

[devilsindetails]

Yes...the ???? Tube is an EF806 Pentode

see:http://www.radiomuseum.org/tubes/tube_ef806s.html

[Firestorm]

This is getting cooler by the minute! As you've likely figured out, "vibrator" is tremolo, not reverb, and it looks like it was an option since it was built in its own box and added in the right chassis cutout. You can trace what part of the preamp circuit it was designed to modulate. Unfortunately the "connection point for tremolo" is obscured by the goop in Tony's found schematic. That schematic, though, may be close. You have a mic input, so that probably goes to the EF804, the trem likely modulates the ECC83 instrument preamp. Could they have used the EM85 as just a power indicator, or does it do something cooler?