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View Full Version : Valencia 846a : Bi-Amp VS replace crossover ?



shill
07-14-2016, 08:32 AM
Hello,

I'm new to this forum and I've been searching for a solution to my problem without success. Probably this subject has been discussed already but I couldn't find the exact answers I'm looking for.

I just came across a pair of Valencias 846a (with 16 ohm speakers), but of one the crossovers is dead. I have no amplifier to drive them, and I have a very tight budget (500 max, I live in france).

I therefore have a few options from witch to choose from :

- Buy new crossovers on ebay and a compatible amplifier. (in this case, which amplifier would you recommend considering my budget ?)
- Forget the crossovers (saving about 200$) and use that money to bi-amp ? (in this case what amps and active crossover should I choose ?)

The goal would be to get better equipement in the years to come, while still being able to enjoy the speakers in the meantime :) !
The music I listen too is mostly modern with a lot of bass, I'm wondering how the speakers are going to react ?

Any help will be greatly appreciated !

S.

Horn Fanatic
07-14-2016, 12:56 PM
Hello,

I'm new to this forum and I've been searching for a solution to my problem without success. Probably this subject has been discussed already but I couldn't find the exact answers I'm looking for.

I just came across a pair of Valencias 846a (with 16 ohm speakers), but of one the crossovers is dead. I have no amplifier to drive them, and I have a very tight budget (500€ max, I live in france).

I therefore have a few options from witch to choose from :

- Buy new crossovers on ebay and a compatible amplifier. (in this case, which amplifier would you recommend considering my budget ?)
- Forget the crossovers (saving about 200$) and use that money to bi-amp ? (in this case what amps and active crossover should I choose ?)

The goal would be to get better equipement in the years to come, while still being able to enjoy the speakers in the meantime :) !
The music I listen too is mostly modern with a lot of bass, I'm wondering how the speakers are going to react ?

Any help will be greatly appreciated !

S.

IMHO, you have a great pair of speakers to start with. ALTEC passive dividing networks are very much old school design from the 1950's. I would suggest that you use an active dividing network so you can bi-amp. Used active crossovers can be found cheaply if you have the patience to wait for a good deal. I have two Crown VFX 2A crossovers that have served me well. The down side of using an active crossover is that you will need two stereo power amplifiers. One of low power for the horns, and one of higher power for the woofers. If you don't mind using solid state equipment the Crown D60 or D75 would be a nice choice for the horns. The bass amp should be of the 100 watt per channel type, just for the head room.

Bill Hanuschak at Great Plains Audio has a passive network he designed for the Model 19, but I wouldn't consider it an audiophile grade unit. I think he sells them for around $175 each. He designed them without the necessity of an L-Pad.

If you have the patience to score good deals on vacuum tube power you would not be disappointed. You could still use a solid state dividing network. Your choice of pre-amp of course, is subjective.

Good Luck,

H.F.

BTW - Welcome to the forum.

P.S. A word of caution. The 846A is rated at 50 watts. Treat them gently.

Joseph Smith Jr
07-14-2016, 02:18 PM
Hello,

I'm new to this forum and I've been searching for a solution to my problem without success. Probably this subject has been discussed already but I couldn't find the exact answers I'm looking for.

I just came across a pair of Valencias 846a (with 16 ohm speakers), but of one the crossovers is dead. I have no amplifier to drive them, and I have a very tight budget (500€ max, I live in france).

I therefore have a few options from witch to choose from :

- Buy new crossovers on ebay and a compatible amplifier. (in this case, which amplifier would you recommend considering my budget ?)
- Forget the crossovers (saving about 200$) and use that money to bi-amp ? (in this case what amps and active crossover should I choose ?)

The goal would be to get better equipement in the years to come, while still being able to enjoy the speakers in the meantime :) !
The music I listen too is mostly modern with a lot of bass, I'm wondering how the speakers are going to react ?

Any help will be greatly appreciated !

S.
What exactly is wrong with the dead crossover and how did you determine that was the case if you currently have no amplifier?

I would suggest repairing the bad crossover, if that in fact is the case, get a decent amplifier and then listen to the speakers for a while first, then you will be better prepared to make a decision as for which way to go further
It is a simple network and would cost you very little to repair or rebuild them as needed to as good as new or better
Then you could properly assess your new speakers

Joe

gdmoore28
07-14-2016, 04:05 PM
I'm with Joe on this one. Spend as little as possible to bring them back to factory specs and use one stereo amplfier. In this case, that means repairing the one "bad" crossover, and that will involve nothing more than testing the capacitors and inductors and replacing the bad one(s). That simple.

Next step: buy a stereo solid state amplfier. With certain Crown amps, you can take care of the necessary CD Equalization onboard the amplifier. Look for a Crown amp (used) that uses "cards" for certain eq shapes; or one that has inboard speaker processing ability.

GeeDeeEmm

shill
07-15-2016, 11:56 AM
Hello, thank you for all your answers ! :)

So I first started looking at amps for bi-amping, and couldn't find the crown amps D60 and D75, they seem pretty available and cheap in the US but not here in France where voltage is 220. If you have other suggestions of amps I am very well interested.

The speakers used to be my grandfather's and I tried saving them a couple years ago and abandoned. Now he passed and they are mine so I'm back at trying to make them work. Just to say that I did the testing a couple of years ago and I think I switched crossovers between the two speakers to find out the problem. The amp that I used back then doesn't exist anymore. The speakers are 16 ohms so I don't know if I can use any kind of amp to drive them ? I have a Samson Servo-260 which delivers 130W per channel. Would that be ok to test the Valencias without harm ?

I didn't know it was even possible to repair the crossover because it is flooded in tar. But I managed to open up the metal case today and take it out,here are a few photos of what I encountered. There is an obvious open connection but it might have been caused by me opening everything up. I know very little about analog electronics but there seems to be very little indeed, even less that what seems to appear in the schematic ! I don't really know how to test these components. I tested continuity inside the piece that says "5 Watts 20 ohm Rockwood" and it's ok. Is that a capacitor ?

Thanks again for your advice,

S.H.

---
Here are the photos, (excuse the poor quality) :

72719
Overall view


72720
Is this a Cap ?


72721
Inductance ?


72722
Is this the L-pad ??


72723
You can see the open connection, a part fell off which connected the wires to the part.

Joseph Smith Jr
07-15-2016, 02:47 PM
Photo ID:
1. Resistor and 2 inductors
2. Resistor
3. Capacitors
4. Inductors again
5. Inductor

Pair of later version ALTEC networks with the backside of the L-pads visible, the round pots in the middle of the boards:
http://img.usaudiomart.com/uploads/large/666103-altec_valencia_846b.jpg

shill
07-16-2016, 05:13 AM
Ok thanks for helping me out identifying the parts ! I've taken everything apart and tested the inductances and caps and they seem to be working fine. The wiring didn't look so great so probably that's where the problem came from. I'm going to rewire everything and test from there !

However I need to be sure that I can use my Samson Servo-260 amp (130W per channel). Is it ok ?

Thanks again,

S.H.

Joseph Smith Jr
07-16-2016, 08:16 AM
Ok thanks for helping me out identifying the parts ! I've taken everything apart and tested the inductances and caps and they seem to be working fine. The wiring didn't look so great so probably that's where the problem came from. I'm going to rewire everything and test from there !

However I need to be sure that I can use my Samson Servo-260 amp (130W per channel). Is it ok ?

Thanks again,

S.H.
As long as it is in good health, that amp if fine
Those speakers are efficient so don't be tempted to go crazy at first, go slow with the power
Your amp has more than enough power to make those ALTECs play loud

If they have been sitting for a long time unused it's better to wake them up easy as well
You will hear the bass improve significantly after a few hours if they have

While you have it all apart I would think it would make sense to change the caps while you are already in there, if they aren't too hard for you to find where you are

I would think, and hope, at least this brand would be easy to find near you! But who knows?:
http://solen.ca/product-category/capacitors/

Joe

shill
07-17-2016, 09:33 AM
Good news I wired everything up and the speaker works !
About the caps, shouldn't I change the caps on both crossovers to keep the same sound on each speaker ?
I'll look into buying a nice amp to go with them.
Thanks for your help :)

S.H.

Joseph Smith Jr
07-17-2016, 10:16 AM
Good news I wired everything up and the speaker works !
About the caps, shouldn't I change the caps on both crossovers to keep the same sound on each speaker ?
I'll look into buying a nice amp to go with them.
Thanks for your help :)

S.H.
Yes, I had addressed that in my last post and then deleted it in order to not put the cart before the horse and go off on some tangent as is so often the case on forums
In other words, make sure everything worked before recommending going out and buying amplifiers, cables, up grades, mods and on and on as people are so oft to do regarding these matters

To answer your question, yes, it is best to re-cap both networks if that is what you decide to do

When you replace your main value caps also add, in parallel, a .01uF film and FOIL by pass cap to each one
Solen makes those as well and you don't need to spend a lot of money on whatever brand it is you buy, just use those of a decent quality
Solen certainly fits the bill on all counts
I would also suggest you clean and re-solder all the connections in your old networks

Listen to your new speakers for a while and enjoy them in the stock but restored network configuration, you may find them to be perfectly to your liking, as is, and negate any need to do anything further other than your already anticipated electronics additions

Glad it all worked out

Joe