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Tube amplifier kit needed to drive low efficiency speaker

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Hi there

i need suggestion on the amplifier kit that can drive 85db sensitivity speaker (that i diy using usher 8945 driver)

any recommendation on excellent sounding amp will be really appreciated.

i already have pre amp and need amplifier which is around 50w or more.

any 300b that can produce that wattage?

thanks in advance
 
Ex-Moderator
Joined 2004
50w is probably in the right ballpark for such insensitive speakers but to expect do that with 300Bs seems a bit optimistic, unless you use 4 of them per channel in parallel PP. That would be rather costly.

I think you have two more realistic options:

(1) Buy or build a less costly amp giving that sort of power, using two 6550/KT88 in UL PP or four 6550/KT88 in triode parallel PP per channel; or

(2) If you would rather build a 300B amp, get more sensitive speakers, say 95dB or more, to allow you to use less power.
 
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Joined 2004
Hi ray_moth, thanks for the reply, seems that its kinda impossible to use 300b, are you in jakarta?
Not impossible, it's just that your speakers don't quite have the sensitivity needed for 300Bs. I'm more used to seeing speakers less than about 88 dB used with SS amps, where lots of power is no problem. I'm not in Jakarta at the moment.

Are there any tube kit available in jkt? any recommended supplier?
I found a few stall holders in the Glodok area, but the problem seems to be availability/reliability of supply. Singapore is better if you can get there and carry your purchases home with you, as accompanied baggage.

If you want to buy a kit and are not planning an overseas trip, I would order what you want from a suitable and reputable overseas supplier who is prepared to ship to Indonesia (many are not!) and pay the cost of having it delivered by one of the better (and, unfortunately, more expensive) carriers, e.g. UPS or DHL. They will ensure your delivery gets into the country and through customs without 'disappearing'.

I once ordered $100 worth of components from Antique Electronics Supply but it was sent by normal post. I got a phone call from someone using a mobile phone on a Sunday, saying he was calling from the Post Office and telling me I should send my driver to meet him at the main post office and pay Rp400,000 to cover import duty (that was twice what I was expecting).

It turned out that the guy was not a postal worker but a thief, working as a customs official, who regularly stole parcels before they got to customs clearance. If the contents were of no use to him (such as the bunch of electronics bits and pieces I ordered), he would phone the person to whom it was addressed and demand money. My driver said he was known to the real postal workers and to the police, who were after him. He was in a great hurry to leave as soon as he had the money and had handed over the goods. That's the kind of risk you take if you use normal post, as you probably know already.
 
ray_moth said:

Not impossible, it's just that your speakers don't quite have the sensitivity needed for 300Bs. I'm more used to seeing speakers less than about 88 dB used with SS amps, where lots of power is no problem. I'm not in Jakarta at the moment.


I found a few stall holders in the Glodok area, but the problem seems to be availability/reliability of supply. Singapore is better if you can get there and carry your purchases home with you, as accompanied baggage.

If you want to buy a kit and are not planning an overseas trip, I would order what you want from a suitable and reputable overseas supplier who is prepared to ship to Indonesia (many are not!) and pay the cost of having it delivered by one of the better (and, unfortunately, more expensive) carriers, e.g. UPS or DHL. They will ensure your delivery gets into the country and through customs without 'disappearing'.

I once ordered $100 worth of components from Antique Electronics Supply but it was sent by normal post. I got a phone call from someone using a mobile phone on a Sunday, saying he was calling from the Post Office and telling me I should send my driver to meet him at the main post office and pay Rp400,000 to cover import duty (that was twice what I was expecting).

It turned out that the guy was not a postal worker but a thief, working as a customs official, who regularly stole parcels before they got to customs clearance. If the contents were of no use to him (such as the bunch of electronics bits and pieces I ordered), he would phone the person to whom it was addressed and demand money. My driver said he was known to the real postal workers and to the police, who were after him. He was in a great hurry to leave as soon as he had the money and had handed over the goods. That's the kind of risk you take if you use normal post, as you probably know already.


I have the same problem in the Philippines, though in the Philippines, the customs officers are the one extorting money from you! :whazzat:
 
Ex-Moderator
Joined 2004
That guy was a customs officer, pretending to be a postal worker.

Sorry to thread jack, but Ray, you mentioned Singapore as a source of kits etc. Where do you go in Singapore? I know of two tube shops in the Burlington Centre next to Sim Lim Square, are there some others you know of?
No, I only know a place in Burlington Centre but I believe there are others.
 
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