A Technical Comparison

Huldra 10, TA-300, TR-200, TR-1000, TR-1010, TR-1020, TR-1040, TR-1050

Considered to be the warmest sounding amplifiers from Tandberg

Among a majority of users of vintage Tandberg receivers it seem to be an agreement that the Huldra 10 (H10) are to be considered "the best" sounding. Or possible more accurate explained, — the warmest sounding of Tandberg's amplifiers with unique timbres and nerve. Much of its sound character stems from its discrete build and the single supply push-pull transistor power amplifier with a big capacitor in series with the speaker output.

Still Huldra 10 second hand prices do not confirm this expressed admiration compared to some other models often mentioned when users ask for buying recommendation of Tandberg amps or receivers.

Trying to better understand as to why this is, and to clear some misconception found online we had a deep dive into schematics and forum posts.

Below we've broken down each model to show some of the differences with focus on amplification function only. With one exception none of the often recommended models should sound "as" a Huldra 10. We asume they all sound good of course, but why would the marked upscale prices on some of those other models rather than the Huldra 10 itself that everyone compares to?

  • Availability could be one major factor. Huldra 10 considered a top model where in production for numerous years. Longer than TR-1000/1010 which got replaced by TR-1040/1055 only two years after introduction. Leaving a lot more or less working H10 still around compared to the more powerful alternatives. Similar can be seen for TA-300 and TR-200 which also values less than they're good reputation would expect.
  • Form factor also seems important. With cabinet width at 53.5 cm H10 are more than 10 cm wider than the 43 cm standard the industry later settled on. When your vintage stereo has to be hidden inside a cabinett, or fit on standard rack shelf this feature might tip the scale in favor of one of the more narrow models.
  • And of course there are users also looking at power rating for more easily finding speakers to fit. Guess the appeal of modern RCA connectors and screw speaker terminals aren't completely worthless either.

Models below are grouped as to how they share service manual

TR-200 first seen in a catalog for 1971-72.
Huldra 10 the following year 1972-1973 together with TR-1000 and TA-300.
TR-1040 P and A are shown in the 1974-75 catalog.

While still being listed in later price lists the TR-1000/1010 are last seen in Norwegian catalog for 1973-1974.

"Closest I came to tube sound without the hassle of tubes"

"Tandberg did well with the transition from tubes to transistors"

anonymous forum members

Huldra 10 2x25W/8Ω

  • Single supply push-pull power amp
  • 61VDC single power rail
  • Seperate transformer windings and rectifier to supply 25VDC to radio/preamp
  • Up until serial number 471500 Huldra 10 had TBA231 op-amp in the phono/riaa stage — then changed it in favour of a descrete transistor circuit.
  • Output transistors: MJE3055/MJE2955
  • Output capasitors: 4700µF changed to 3300µF on later units
  • 2 pin and 5 pin DIN connectors only
  • Later models had many 22µF caps values upped to 47µF throughout all printed circuit boards with no changes made to the schematics.
  • From s/n 483170 accuracy for the FM stereo decoder are better using IC on the main board. But if sound quality for the FM receiver are of importance we are supposed to look for serial numbers from 477000 to 484000 still using transformers. Else later models (as in newer) are noted to sound better for amplification duties.
  • W53.5 H12 D30.5 cm, 8.2 kg

TBA231 vintage equivalents: uA739, MC1303, SN76131, LM1303N, RC4739, XR4739. Modern equivalents: NTE725 and ECG725
While they can substitute each other there are sound differences.

TA-300(M) 2x25W/8Ω

  • Single supply push-pull power amp
  • 59VDC single power rail
  • Power amp share secondary transformer windings and rectifier bridge with the preamp
  • Early models with serial numbers from 1220000 to 1220500 made use of the TBA231 op-amp in the phono/riaa amp just as early H10.
  • Output transistors: MJE3055/MJE2955
  • Output capasitors: 4700µF/40VDC in place - 4000µF shown on schematics
  • With the exception of a simpler power supply the schematics are nearly a blueprint from Huldra 10 without the radio tuners. Even the tuner input makes use of the extra transistor stage (2.7x gain) shared by the phono input after the riaa, — just as it is done in the H10. PCB and chassis layout are somewhat different from H10 and for specimen we've had on the work bench film caps are different brand/type than H10.
  • As H10 the TA-300 has 2 and 5 pin DIN connectors only, even the microphone input
  • Unique features:
    • Two Phono inputs sharing a single riaa/phono amp.
    • Tape Monitor function on both tape inputs for use with tape machines with separate recording/playback heads.
    • Two headphone jacks
    • Stereo Mono-L Mono-R, — all in L/R swap places
    • The TA-300M model has microphone input with a fader to mix with any selected source before the power amp. Can not be routed to tape out.
  • W43 H8.7 D24.3 cm, 5kg

TR-1000/1010/1020 2x35W/8Ω

  • Single supply push-pull power amp
  • 64VDC power rail
  • Seperate secondary transformer windings and rectifier to supply 25VDC to radio/preamp
  • Seperate secondary transformer windings, rectifier and 3300µF cap for each power amp channel oddly enough, H10 has better channel seperation (crosstalk) given Tandbergs numbers are ment to be read as negative numbers like -60dB/1kHz vs TR-1000's -52dB
  • TBA231 op-amp used in the phono/riaa stage using indetical circuit as seen in early Huldra 10. Not changed until sometime into TR-1040
  • Output transistors: MJ802/MJ4502
  • Output capasitors: 3300µF
  • RCA and 5 pin DIN connectors
  • Speaker terminals with screw posts and 2 pin DIN
  • RCA have different impedance with higher output voltage (changing two resistor values give H10 similar line output voltage)
  • Unique features:
    • Seperate Left/Right bass & tremble control
    • Can be used as preamp with Tape 3 Preamp Record activated
    • TR-1000 FM only
    • TR-1010 FM/AM
    • TR-1020 FM/AM different AM board to TR-1010 possible US only including ferrite aerial?
  • W43 H12 D30.5 cm, 8.8 kg
From 1972-73 catalog and price list we learn the TR-1010 with FM/AM tuner at the time being defined a special version of TR-1000, — at the time costing exactly the same as Huldra 10 when introduced.

Trying to understand how Huldra 10 has its long production run it seems it were aimed at the radio listener wanting the best possible radio receiver. Keeping the well renowned model name Huldra 10 had at least four upgrades throughout its lifespan. The phono amp and the others to better the FM tuner.

While TR-1000 more excited people looking for a hub for they're music gear — with more power, phono input and up to three tape machines. All this at a tiny bit lower cost. It nevert got the upgradet phono amp from H10 before it where replaced by the more powerful TR-1040 which also first started out with the TBA231.
Sølvsuper 11 (1970) also made use of 2N5496/2N5496 from the upgraded 2x20W/4Ω version (autumn 1971). Together with a new main transformer with higher voltage from 44 to 50V. Which also included separate secondary transformer windings for the back light bulbs. SS11 are considered the best sounding of the entire SS range and probably the best selling receiver by Tandberg. In 1972 the SS11-73 facelift were introduced now with square buttons similar to H10.

TR-1040/1055 replaces TR-1000/1010/1020

  • Dual supply push-pull power amp
  • TR-1040 2x40W/8Ω, +/-40V dual power rails
    TR-1055 2x55W/8Ω, +/-45V dual power rails with seperate secondary transformer windings, rectifier and 4700µF cap for each power amp channel
  • Seperate secondary transformer windings and rectifier to supply 25VDC to radio/preamp.
  • Models with serial numbers up until 1426000 made use of the TBA231 op-amp in the riaa/phono. Then switch to discrete transistor circuit with close resemblance to Huldra 10 throughout
  • Output transistors: MJ802/MJ4502
  • Output capasitors: None, — not needed with differential power supply alternating at 0 volt. No longer having a cap to block DC offset errors at startup and power down a relay on the speaker output are introduced on this model.
  • For TR-1055 there are a simplification to power amp circuit from serial number 1426401 bringing it closer to TR-1040 now only differentiated by the PSU
  • Model name ending with P have preset buttons for FM radio stations
    Model name ending with A have AM radio and FM (launched late 1974)
  • RCA and 5 pin DIN connectors
  • Speaker terminals with screw posts and 2 pin DIN
  • RCA Preamp Out and Power-Amp Inputs on US version
  • Level trimpots for line inputs on the back (loading source signal to ground)
  • W44.5 H13.5 D31 cm, 9 kg

TR-200 2x15W/8Ω

  • Single supply push-pull power amp
  • ??VDC power rail
  • Power amp share secondary transformer windings and rectifier bridge with the preamp and radio
  • TBA231 op-amp used in the phono/riaa stage using indetical circuit seen in early Huldra 10
  • Output transistors: 2N5496/2N5496
  • Output capasitors: 2500µF shown on schematics
  • Simpler circuit throughout with no Hi/Low filters
  • W43 H8.7 D24.3 cm, 5 kg

To summarise none of the suspects seem to have all the whistle and bells one would desire underneath one single wooden cover

The mother of all, the Huldra 10 could benefit from having the transformer and power supplies from the TR-1000. Combined with RCA in/outputs with corresponding voltage levels — luckely later are a very easy fix. The soon to become 50 year old 4700µF cap in the power supply need to be replaced anyway, fitting a 10.000µF cap in its place are an easy fix to noticeably better the power supply — this without having to implement any inrush scheme.

TA-300's simpler mains transformer with power supply makes it so it doesn't quite reach up to H10 standard. But still it is the closest contender of the bunch seen from a technical standpoint. TA-300 also respond well to better and bigger caps in the power supply. It's also have an line input with a active circuit (2.7x gain) before the volume control if driving a weak sourche are needed which H10 and TR-200 are missing.

TR-1000/1010 are thoughtfully build and somewhat easier to implement into a modern stereo system with its RCA connectors and line levels. It misses the discrete phono preamp/riaa which came back with TR-1040 and continued with Huldra 11/12 and most if not all of the series TR-2000. There are some users that actually prefer this op-amp circuit over the discrete version.

TR-1040/1055 being the first receivers with dual voltage supply, starting the trend from Tandberg building more powerful output stages with new set of design challenges and new overall sound coloration. That said, everything else about them are desirable where also the discrete phono riaa/preamp came back from s/n 1426000. They still use the same output transistors as TR-1000 but the differential power supply now have a total voltage swing of 80 and 90VDC — up from 64VDC in the TR-1000.

TR-200 may possibly originate from HiFi-FM, — i.e. years before H10. Owners says this amp sounds sweet and punch harder than what it seemenly should be capable of. It has the same IC phono amp as TR-1000/1010 and what looks like a very scaled down H10 scheme. Some of the simplification might even be considered favorable for vintage gear with less mechanical switches to accumulate contact issues.
Huldra 8 (1965) are another Tandberg receiver that have it's fanbase. It's a hybrid with tube radio tuners and transistor pre-amp and single supply push-pull power amp. Tone controls are a little unusual inserted into the power amp feedback. Measuring W83 x H23.7 x D25.2 cm and only outputting 2x10W/4Ω it possible do need some extra charm to keep it out on the stereo bench.

Huldra 9 (1968) still uses tubes in the radio tuner. For it's time the ultra modern appearance still seem to provoke collectors today. It's 2x25W single supply push-pull power amp and FM tuner supposedly sounds good.

HiFi-FM (1968) are sometimes referred to as an early TR-1000 (1972). Not being branded Sølvsuper and sized similar to TR-1000 might be the main reason for this. With only 2x15W and schematics much closer to TR-200 (1971) with its simpler power supply, 2x2N5492 output transistors and DIN only connectors one could argue how accurate this is.
HiFi-FM seem to be an important piece in the transition to what would become Huldra 10 — as an all transistor receiver being released around the same time as the top model Huldra 9 which still utilizing tubes in the radio tuners.
From reading many years worth of internet posts our interpretation became that we are to believe models listed here are the last of Tandberg's golden sound era. Or romatic, ear-friendly and non analytic time period as others may call it.

Later models from Huldra 11 (TR-2025MB), Huldra 12 (Multi Band version of TR-2030*) and the rest of series TR-2000 including later series 3000/4000 all made use of todays more traditional differential amplification technology, — by some defined as more analytic and cold sounding. Maybe with the exception of TR-2075 mkI and TR-2055 both actually from the end of this period we've not been able to find this kind of praising for a single product line like these models that sprong out of the Huldra 10 timeline.

*TR-2030, TR-2030L, TR-2045 and Huldra 12(MB) all share parts list. H12 2x32W later came in a more powerful 2x60W version.
From the sixties the Huldra branding were used by Tandberg on the best possible receiver they at any time where able to produce. Sølvsuper series often referred to as SS in short form where more aimed at the mass marked where some cost cuts could reflect on product quality compared to the Huldra range.

Increasing model numbers are how they evolved. I.e. Huldra 10 replaced H9. Sølvsuper 11 replaced SS10 and so on.

To view high resolution images, right click on image and select View image or Save image

Select file from list below

771.6K Compressed file
2.7K Compressed file
h10_quiescent current_adjustment.JPG

Some comprehensive Tandberg archives here

Norsk Radiohistorisk Forening




Your comment are welcome


Email: optional, will be hidden


Please do not make support question private as it brake with what this site is trying to do which is to share information to many with multiple contributors
All spam is reported adding to your international IP blocking quota.