Author Topic: Steinhart Schematic  (Read 10537 times)

Offline Family_Dog

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Steinhart Schematic
« on: January 07, 2013, 07:39:02 AM »
Due to an apparent upsurge in popularity of theSteinhart amplifiers, I am attaching the schematic as a "Sticky".

I have a hand-drawn the Steinhart diagram that I scanned some six years ago, from an original sketch done by Gunther. I was after the one with the KT88 valves, the sketch he gave me was for PL519 outputs. He crossed out the PL519 and wrote KT88 in his own handwriting and said "It's the same thing". Filament voltages differ as do the valve base pinouts. He uses a -50V Bias supply here. My amplifier does not have any semiconductors bar the BU208A in the 450V supply. The cathode voltages should be set at 2v for the KT88 valves, this may differ when using PL519 valves.

A word of warning: Gunther did not fit bleeder resistors to discharge the smoothing caps, I fitted some myself. If the caps are not discharged, they store energy, which you will soon discover when the AC power is off and the caps discharge through your fingers.




Pictured below is my TVP800 Amplifier.





-F_D



-Eric

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Offline Mars

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Re: Steinhart Schematic
« Reply #1 on: February 22, 2013, 09:43:49 AM »
Here is a schematic of the TVP77

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Offline Mars

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Re: Steinhart Schematic
« Reply #2 on: February 22, 2013, 10:14:16 AM »
Bolero Schematics


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Offline Mr_T

Re: Steinhart Schematic
« Reply #3 on: May 31, 2014, 10:51:52 AM »
Hi  I have two Bolero Mono Blocks.  Is there any way to introduce a better / easier bias method?  Also the valves were not mounted in a base - but wires soldered to the valve.  Should we not put bases on?  I thought maybe putting a bit of a silcon sheet between the valve and the PC board as an option?  What could I sell these for?

Offline Family_Dog

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Re: Steinhart Schematic
« Reply #4 on: May 31, 2014, 01:01:22 PM »
I do not know the Bolero, but I do frown upon wires soldered directly to the valve base. Cost-cutting! - But to my mind a cheapskate way of doing things. You definitely want to keep the output valves away from the PCB to avoid heat-transfer and subsequent damage to the PCB. Perhaps Mars or Ampdog might be more familiar with this model.

Petty complaints aside, Steinhart amps in general sound very good!


-F_D



-Eric

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Offline Hi-Phibian

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Re: Steinhart Schematic
« Reply #5 on: May 31, 2014, 05:01:10 PM »

I do not know the Bolero, but I do frown upon wires soldered directly to the valve base. Cost-cutting! - But to my mind a cheapskate way of doing things. You definitely want to keep the output valves away from the PCB to avoid heat-transfer and subsequent damage to the PCB. Perhaps Mars or Ampdog might be more familiar with this model.

Petty complaints aside, Steinhart amps in general sound very good!


-F_D

In Gunther defense, these were made in a time before the internet, before certain revivals and the opening up of former communist countries still making tubes and bases. My understanding is they were just virtual unobtainium here back then. I am sure had they been on APs shelves, he would have used them.
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Offline Ampdog

Re: Steinhart Schematic
« Reply #6 on: June 07, 2014, 04:03:08 PM »
Only about 17 months late ....

In the first diagram, looking at the leftmost ECC83 triode: I hope the 47µF cathode bypass capacitor goes to the junction of the 2K2 and 100E cathode resistors and not ground (common) - otherwise no feedback ....
Audio must be the only branch of engineering where lack of basics' knowledge is considered a superior form of wisdom. (Anon)

Offline Family_Dog

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Re: Steinhart Schematic
« Reply #7 on: June 07, 2014, 04:26:17 PM »
Good point, never even noticed that. I will need to check the amp at some stage.


-F_D



-Eric

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Offline Mr Valve

Re: Steinhart Schematic
« Reply #8 on: August 04, 2015, 09:21:00 AM »
Good morning all

Maybe a bit late ...

I have a few Steinhardt diagrams on file ... Please contact me if I can be of any help.

Regards
Sanita

Offline PaulMo

Re: Steinhart Schematic
« Reply #9 on: January 09, 2016, 09:18:04 AM »
Hi All

I've got a Fidelio (102DD) to repair for a friend. It was making popping sounds on L channel and one valve was as good as a microphone, it was so microphonic!

However, a matched pair of 6n45C's from Sanita later, its purring like a kitten again.

It would be handy to have the diagram, if possible. It uses 5814 x2, 12BH7, and 6n45C x2. Anyone have this diagram?

Sound-ly yours
Paul

Offline entropyagent

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Re: Steinhart Schematic
« Reply #10 on: January 12, 2016, 09:40:21 PM »
Maybe none of my business, but....if Mr Valve is retiring, perhaps it might be worthwhile to request copies of the generously offered diagrams? For posting here, perhaps, and maybe copies to Cape Town Hi Fi club? Are there equivalent organisations in other centres?

These treaures need to be preserved for posterity.

Offline Family_Dog

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Re: Steinhart Schematic
« Reply #11 on: January 13, 2016, 07:59:15 AM »
Excellent idea! Sanita, if you like, I will upload them here. Please contact me per PM or the address you hav for me on file (Eric).


-F_D



-Eric

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Offline PaulMo

Re: Steinhart Schematic
« Reply #12 on: January 22, 2016, 08:47:49 PM »
Hi Guys

Is it worthwhile, while I've got the Fedelio (102DD) in my mitts, to trace the circuit out? I'm tempted to do that for my own purpose, but external interest will motivate me even more!

I particularly want to re-design the PCB using ceramic valve bases instead of the round support rings and the slide-on connectors. When you work on the PCB, the tracks and pads are so puny that more damage is caused.

I would like to have a copy of the TVP-102 circuit, as well as the TVP-1 Differential Valve Preamp. My pal has all three devices and would be great for maint purposes.

Last thing - the transistor fine-bias drawing on the Bolero Junior Output circuit is wrong (?)> The BD140 tranny is a PNP and the pins are 1-e, 2-c, 3-b (from left to right). Anyone else notice this? How effective is this system?

Paul

Offline Family_Dog

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Re: Steinhart Schematic
« Reply #13 on: March 28, 2016, 09:05:14 PM »
Thanks to fredeb who obtained 22 Steinhart schematics from Mr Valve. Many thanks to both of you!

These may be downloaded from this link:

https://www.dropbox.com/sh/uoc7k1ik06a2hfz/AACXa4CL2HvqurJy9gyOBSaza?dl=0

The following Steinhart Schematics are listed:

STEINHART SCHEMATICS
Bolero Junior - TVP171 Input Stage.pdf
Bolero Junior - TVP171 Output.pdf
Bolero Junior Input Stage.pdf
Bolero Junior Output.pdf
Bolero Junior PS.pdf
Bolero Junior.pdf
Bolero Juniorb Instructions.pdf
Bolero.pdf
Bravura MK2.pdf
DVP-1SE PS.pdf
DVP-1SE.pdf
DVP-6H30 Pre amp.pdf
Head Amp.pdf
PCU.pdf
Pre amp.pdf
ProSound.pdf
TVP-777VH.pdf
TVP-77UL.pdf
TVP102 Out + PS.pdf
TVP102 Sound Stage.pdf
TVP102.pdf
TVP502.pdf


-F_D
« Last Edit: April 02, 2016, 08:02:26 PM by Family_Dog »



-Eric

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Offline Dark Angel

Re: Steinhart Schematic
« Reply #14 on: May 08, 2016, 08:30:29 PM »
I'm rebuilding a TVP 200, does anyone have schematics for it?