L 300 summit.

[Gary L]

Jan, You are in the right place but I am not the one to help you with the JBL 300s.

If you use the search function here and type in JBL 300 or L 300 Summit you should have a few nights of reading about all the info you are looking for.

As with many of these great vintage speakers, many changes took place durring the life of their production.

Even after they stoped making them many members here have embarked on a mission to make them even better. I'm not sure of the success of these projects but I think if you read some of the info from those who are reliable JBL experts then you should find the answers that will direct you to the correct parts.

Gary

[matsj]

4 Aleph X pcb is bought from a Swedish hififorum member and i´m going to use 2 of them for the L300.
Looking for a B460 to have with L300.

mats

[Zilch]

Jan:

All of the necessary information is in these forums.

Spend a weekend with "Search" to reveal it.

Secret word: "4333."

Example: All ring radiators have the same impedance. It doesn't matter what they say on the foilcal....

[JohanR]

Nice ones, Mats!

[Donald]

FWIW, as of 06:47 PST today $1500 US = 9529.35 kronor.

[matsj]

Donald: I paid 10000 swedish crowns for them so that is : 1 535,06 USD

mats

[RKLee]

NICE! Congrads.

.
.
Does someone know how many L 300 there are buillt ?

mats

I think you will never find out exactly because those records were lost during the Northridge Earthquake. JBL's corporate HQ is in Northridge Calif, in the San Fernando Valley. The Los Angeles area suffered some serious damage, and JBL was litterally at the epicenter.

[matsj]

Today after work have i been playing with a Crown D-75 amp on my L300. I have borrowed it from Torbjörn "Topr" and i´m very thankfull for that. I really like the sound from it, but i think i need moore power to be satisfied . I´m building 2 Pass Ax-100 mono amps to them in spring and i think that will be awesome together with a Pass P1.7 pre amp.

Last night i tried it on my K2/array hybrids 2435 drivers and there where also the sound very good. I had a Crown K2 to the Le14H-3 and this really kick ass . The d-75 may not sound as good as my 5 w class A Diy amp but the difference is not huge.

If there is someone looking for a smaller amp i really can recomende these crown amps ( D serie ).

mats

[richluvsound]

check out macaroonie's back yard build

there are a lot of variations possible.

Rich

[BMWCCA]

If there is someone looking for a smaller amp i really can recomende these crown amps ( D serie ).

I'm assuming you meant D75. As we've discussed here before, the D75 is sweet but it's outrageously overpriced used compared to the D150A-II or the DC300A-II simply because it's only one rack space. If you like the D75 I think you'll probably like the larger D-series amps or their improved offspring the PS-series: PS-200 and PS-400 which are often even cheaper than the D-series and have some nice updates. I recently found a perfect PS-400 for just over $100 USD. You probably spend more than that much every week on beer in Sweden!

[hjames]

... I think you'll probably like the larger D-series amps or their improved offspring the PS-series: PS-200 and PS-400 which are often even cheaper than the D-series and have some nice updates. I recently found a perfect PS-400 for just over $100 USD. You probably spend more than that much every week on beer in Sweden!

Sounds interesting - I just checked the specs n the PS-400 - but, 165w/ch - whats the next up from that? something around 200-300w/ch range ...

[BMWCCA]

Sounds interesting - I just checked the specs n the PS-400 - but, 165w/ch - whats the next up from that? something around 200-300w/ch range ...

Hah! Bridged PS-400s? You'd have to go with Scott's Macro-Techs to get more power, but they'd have fans. Then you'd be into serious power, at a serious price. Actually, depending on how you're comparing rating systems, the PS-400 is probably more like 190 watts per channel @ 8 ohms. And 660w bridged-mono at 8 ohms. Yeah, I said 660. Remember the DC300A and PS400s were commonly used in movie theaters. I'm pretty sure they could fill a living room.

For perspective, the D75 I think Mats was talking about up above is rated at 40 watts per channel and Mats liked it! That's what I was talking about.

Macro-Techs range from 210 wpc/605mono to over 1,300 wpc/4,000 mono. Want me to bring a PS-400 and PS-200 up for you to play with?

[subwoof]

The D and PS series uses the standard bipolar power supply and AB=B output design. There is absolutely no difference between the 300 and PS400 except for the additional "mute" chip after the input opamp. same power supply, outputs, etc. 165 on the sheet, about 200 real world if you can give them 120V.

The crown grounded bridge design was first introduced around 1970 with the M600. It was simply TWO DC300A's that were bridged together into a SINGLE channel. 89lbs..

That amp had a short-lived custom studio version called the delta omega ( about 200 were made ) that used a feed-forward circuit to sharpen the attack on the waveform. It REALLY worked great on big soffitt monitors.

A bridge in electrical terms means a circuit with 4 sides - the crown M600,MT,MA,PB,PT,CT and others share the same design but in/out/display/card/etc changes were made depending on the various lines.

small = MA600 / PB1 = 220 @8
med = MA1200 / PB2 = 320 @8
large = MA2400 / PB3 = 570 @8
stupid = MA10,000 = 10,000 into .25 ohm

VZ3600 = 750 @8
VZ5002 = 1200 @8

The studio / low noise models ( studio / macro reference ) used the same output section as the MA2400 but had a special power transformer and a $$ fan that made it SUPER quiet - this is the most powerful crown made with a linear amplifier whose fan won't suck in small children and edges of carpets.

The newer designs ( BCA ) are a grounded bridge with special current limiters to make sure the newer devices ( mosfets ) behave and share the power equally. These are the K,CTS,Itech,etc.

Anyways, if you are looking for MASSIVE energy storage amps that are killer for studio monitors or sub use, The M600 is rated at 600/1400/2000 into 8/4/2 and stores enough energy to be useful as a spot welder. I have about 12 of them that I will be restoring in the spring when it gets warm enough to work on these in the shop. At nearly 100lbs each it's a serious workout to shuffle these around all day.

When done they will have the latest high power output devices ( 32!! ), new main and LV caps, tweaked drive /bias circuits and a custom input card assembly with filters, crossovers, etc.

sub

[matsj]

I was wrong about the amp number, yes its a D-75. I have allways wanted a Crown Studio reference 1 but you can´t find them here.

mats

[johnaec]

stupid = MA10,000 = 10,000 into .25 ohm

Isn't that called an arc-welder?

John