Threshold SA4e, woolly sound?
I bought this amplifier two years ago. I have a feeling it’s not sounding quite as it is supposed to. The bass and low-mid-range is really woolly and have low energy. There is no punch or definition. It sounds kind of sweet in the highs but tired and sloppy in the low ends.
The power supply capacitors, power button and thermistors were recently replaced with parts obtained from Threshold Audio Inc. The replacement was performed by a non-Threshold-authorized but none-the-less knowledgeable audio engineer. It did not help the issue. The bias was adjusted at the same time. The bias might be correctly adjusted or it might not be, I have not checked it myself. However, the issue was/is present both before and after the supposed bias adjustment.
Since this is my first Threshold amp I don’t know for sure how a Threshold amp is supposed to sound, but I can’t in a million years imagine that Threshold built its name on a sound such as this. There has to be a technical issue somewhere. The phenomenon is present with several pre-amps, also sufficiently good ones.
Does anyone recognise these symptoms? Is there anything I can do to help potential diagnosis? I cannot say I have any expertise in the electronics part of DIYing but I can probably perform some measurements if need be.
Thankful for any input,
Cheers
I bought this amplifier two years ago. I have a feeling it’s not sounding quite as it is supposed to. The bass and low-mid-range is really woolly and have low energy. There is no punch or definition. It sounds kind of sweet in the highs but tired and sloppy in the low ends.
The power supply capacitors, power button and thermistors were recently replaced with parts obtained from Threshold Audio Inc. The replacement was performed by a non-Threshold-authorized but none-the-less knowledgeable audio engineer. It did not help the issue. The bias was adjusted at the same time. The bias might be correctly adjusted or it might not be, I have not checked it myself. However, the issue was/is present both before and after the supposed bias adjustment.
Since this is my first Threshold amp I don’t know for sure how a Threshold amp is supposed to sound, but I can’t in a million years imagine that Threshold built its name on a sound such as this. There has to be a technical issue somewhere. The phenomenon is present with several pre-amps, also sufficiently good ones.
Does anyone recognise these symptoms? Is there anything I can do to help potential diagnosis? I cannot say I have any expertise in the electronics part of DIYing but I can probably perform some measurements if need be.
Thankful for any input,
Cheers
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what is missing , while certainly complicated to get , is proper pic of FE board , taken from parts side
frankly - this issue is for Guru .....
frankly - this issue is for Guru .....
Hello Gulahuset
What about possible woolly preamplifier impedance and what is your audio source and speakers parameters ?
Amplifier are not always alone responsable for his perfomance in the audio chain 🙂
Sorry for my ineptitude, where can I find the FE board?
One side hovers around 47°C and the other around 50°C as measured with a digital oven thermometer with a small piece of foam on top to minimize the cooling effect on the sensor bit. My brother (who has the SA4e at this moment) can hold his hand 6-7 seconds on one side and 4-5 secs on the other.
Hi Soundhappy
Of course, good point!
Up until now, I haven't used proper preamplifiers to the amp as I've been waiting for the right one to come out. In the meanwhile, I have used pre-outs on already owned integrated amps (Krell KAV-300i and Accuphase E-305) with a resulting woolly bass. The integrated amps on their own have better bass than when coupled with the SA4e. I have attributed this effect to the integrated amps being sub-par preamplifiers (impedance mis-match for example) to the Threshold amp. I now (only since a few days) have a Treshold FET ten/e and it sound much better with the SA4e than the integrated amps as preamps, but the woolly effect remains. I use a TEAC VRDS-25x as source and listen on Infinity Renaissance 90 speakers which are capable of dry and punchy bass.
Thanks for the replies and invested interest.
Hello Gulahuset
Maybe you can try with digital multimeter verify if all carbon composite brown colour resistors
ohm value was not drifted too much. Can happen after many years
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