Like I said
anyone to say EPDR (combination of impedance and -phase angle) "does not matter", is dreaming.
The odds are very against you sunshine. Over and out👎
The odds are very against you sunshine. Over and out👎
Preamp and impedance question
I am asking a custom builder to build an amp using Luxman mq-300 schematic. I have two questions:
1) the Mq-300 is a power amp. I don’t have a preamp. Can I just add a volume pot to a power amp schematic? I did some research about passive preamp, but it seems even a passive preamp has a circuit and a transformer. Is it better to buy a separate passive preamp?
2) the transformer is designed for 8 ohm. If I want it to support 4 ohm, I need to upgrade the transformer. I know that the speaker impedance curve can dip to 5 ohm at 30Hz. Is it important to have 4 ohm support?
thanks.
1) the Mq-300 is a power amp. I don’t have a preamp. Can I just add a volume pot to a power amp schematic? I did some research about passive preamp, but it seems even a passive preamp has a circuit and a transformer. Is it better to buy a separate passive preamp?
2) the transformer is designed for 8 ohm. If I want it to support 4 ohm, I need to upgrade the transformer. I know that the speaker impedance curve can dip to 5 ohm at 30Hz. Is it important to have 4 ohm support?
thanks.
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- 46 posts total
George, Everyone reading this thread can see that I and atmasphere talk in very specific terms and in detail when we talk about EPDR. You are not fooling anyone but perhaps yourself. Since you are such an expert on EPDR, tell everyone, specifically, what was inaccurate about atmasphere's post about tube amplifiers and EPDR. Here, I am reposting the relevant section: Tubes are a bit different from transistors in a number of ways as we all know :) One of the ways they are different is the Safe Operating Area (SOA). With tubes you can exceed the SOA without damage to the tube if the tube is allowed to cool off afterwards. A tube dramatically overtaxed, such as in a loss of bias, can turn cherry red from heat, but if allowed to cool off, and the problem corrected, can continue to give normal service. |
atmasphere Yes it was, as this is what I answered to below, saying a 4ohm transformer would be a very good idea as that speaker "5ohm is a nominal figure" you can bet it goes down to 4ohm or even lower, and when combined with any -phase angle (epdr) could be even lower again. gte357s 2) the transformer is designed for 8 ohm. If I want it to support 4 ohm, I need to upgrade the transformer.The OP needs a 4ohm tap if not 8ohm also end of story!!!!!!!!! That MQ300 Lux had one, you two are dreaming to think he only needs an 8ohm tap with that amp he’s getting built, and will have better resale value with both taps. |
- 46 posts total