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S-Ruddy's Executive IV Restoration Thread

larryderouin said:
If anything changing the caps will give you a more detailed bass, without increasing the bass. The loudness switch is designed for the exact conditions you are using it for. There is a curve that describes how you hearing perceives frequencies at certain volumes. These are known as Fletcher-Munson curves. Here's some light reading. https://www.google.com/url?url=https://en.wikipedia.org/wiki/Fletcher%E2%80%93Munson_curves&rct=j&frm=1&q=&esrc=s&sa=U&ved=0ahUKEwis5t282_jMAhVo04MKHbAeAjsQFggUMAA&usg=AFQjCNGlm2IhF7vN8EiFAY0fq3VenUv_aA

Basically at low volumes bass and treble appear to be attenuated more than mid range frequencies. So the bass and treble frequencies get boosted either by application of the Bass and treble controls, or the loudnes control or for the more extreme guys, Both. As volume increases, Bass and treble boost is attenuated down to normal levels, with the loudness eventudally being non functional somewhere near 1/2 volume (by knob position).
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Well then I will definitely change the caps. More detail would be greatly appreciated.

BTW I traced the source of the loud buzz to the interconnect from the tuner to the amp. I was really sweating that! Those old cables need to be replaced or at least fitted with new RCA plugs. Also I have never come across any threads were someone has replace the RCA inputs. I won't do it on this restoration but am definitely thinking of doing it to my x-202b. Those old RCA inputs are really crap even if they are re tensioned.
 
I have made yet another turntable change. I started cleaning the original RC-88 and wasn't entirely happy with the results so I decided to restore a better looking RC-98 instead. Well after transferring all the mechanism underneath the plinth from the 88 to the 98 I started on the motor. I discovered the adjustable speed adjustment resistor is toast. The plastic piece that the coil is wrapped on is broken and probably beyond repair. I have a WTB in Barter Town but if anyone knows were I can get one please let me know. If not I'm going to have to figure out how to install a new readily available one. Let me know if you have any ideas. I would hate putting in the 98 and have that feature not working.
 
I have the RC-98 back together. I have used the motor from the original 88 so no functioning speed control. :( I found a Shure M3D in my stash and will be using that for stereo 45 and 33 play. I plan on putting a cart in another headshell for 78 playback. I need some recommendations as I don't have anything but an Alcos 73 and I don't think it will fit the headshell. Also I'm assuming the 78 input is for changing the phone preamp from magnetic to ceramic, is that correct?
 
If the 78 cart is magnetic similar to the M3D and is a 1/2" mount, 1.) it should fit the headshell , 2.) it shouldn't need anything other than plugging into the tonearm.

the "78 monoraul" is a switch position on S1 to equalize the phono preamp for 78's. Then you have LP MONO and a couple of RIAA (stereo) positions. Basically S-1 is an EQ selector for the 1st 5 (including the TAPE position) and source selector for PHONO (4positions), Tape(1 posit), Tuner (1 posit), and Aux (2 posits).

You picked the right FISHER to give you prematurely white hair, with many bald spots from pulling your hair out at all the combinations of RIAA, non RIAA, mono, rev mono, stereo, rev stereo, AM-FM simulcast, FM-FM stereo, MPX Stereo, etc....:biggrin:
 
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larryderouin said:
If the 78 cart is magnetic similar to the M3D and is a 1/2" mount, 1.) it should fit the headshell , 2.) it shouldn't need anything other than plugging into the tonearm. What 78 input are you talking about?
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Just read the owners and service manuals. There is no 78 input on the amp input panel just a 78 selection on the amp input dial. RIAA 1 input underneath is for mag and ceramic carts you just select which your using via front dial.
 
Watch the gain on the ceramic cart. It would be fine on AUX, but with all phono positions going thru the phono preamp, I would think it's gonna overdrive something real quick. also with more modern magnetic carts the resistive load of 100K is higher than they expect. The m3D is probably ok (check the specs) but a more modern shure would expect 47K to as high as 68k. i closed out the manual already but it's the 1st resistor to ground side on Phono 1 (R90 or R91 I believe).
 
OK so I need to change input resistance on RIAA 2 from 100K to 50K. What do I need to replace??

I wonder why they made RIAA 1 and 2 different. They didn't even mention it anywhere that I could see.
 
Mainly the different manufacturers had different input specs. All you need is a couple of 47K resistors and replace the 100k
 
A couple of comments if I may --

1. It is often far easier to add a 91K resistor across the jacks that you are intending to bring down to 47K. The existing 100K resistors are often buried on the selector switch of the phono preamp sub-chassis, and very hard to get to.

2. The different input impedance specifications for RIAA 1 and RIAA 2 are in fact mentioned in the owner's manual.

3. The different input impedance between the two inputs was to provide greater versatility, at a time when a standardized load impedance hardly existed.

Dave
 
dcgillespie said:
A couple of comments if I may --

1. It is often far easier to add a 91K resistor across the jacks that you are intending to bring down to 47K. The existing 100K resistors are often buried on the selector switch of the phono preamp sub-chassis, and very hard to get to.

2. The different input impedance specifications for RIAA 1 and RIAA 2 are in fact mentioned in the owner's manual.

3. The different input impedance between the two inputs was to provide greater versatility, at a time when a standardized load impedance hardly existed.

Dave
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Dave,

Looks like I may not need to add the resistor. I finally found info on the AcoStereo 73. I will be using it in the Garrard RC-98 for 78 playback. It is a ceramic cartridge so I can use Aux inputs. I won't be able to use the Shure M3D for stereo playback on the Garrard like I planned but the Acos uses a flip stylus. Cons are probably less quality stereo playback and since it requires the aux input I don't think using the 78 or LP selector will work. At least this leaves RIAA 1 and 2 open for the Miracord which will be the main player. Then I will have two loading options for it.

I could not find the impedance info you did in the manual. Maybe my manual is different than the one you have or I'm blind which could be quite possible. Just curious what page you saw that on.
 
I installed the TT last night. I used an old stylus in the Acostereo 73 crystal cartridge and hooked it up to aux 1. And didn't get any sound. After checking continuity of the headshell and arm to end of interconnects everything checked out fine. So looks like the cart is bad. This is a bummer as it would have been the perfect solution to my duel TT set up. I then plugged in the headshell from my Contemporary Console. It houses a GE VR II with a flip stylus. I used RIAA 2 which calls for the 100k which matches that cart. It played and sounded great! So I could find another one to use but I won't have stereo playback on the Garrard. Does anyone know of a vintage stereo cartridge with a flip stylus that I could use with the RIAA 2 or aux inputs. I would like it to sound as good as the GE or Shure mono carts I have.
 
Stanton 500A. No flip stylus, but you can get a 78 stylus for it, and just swap them when you want. It's almost as loud as the GE VR and you can run a lighter stylus wieght (VTF) than the VRII.
 
larryderouin said:
Stanton 500A. No flip stylus, but you can get a 78 stylus for it, and just swap them when you want. It's almost as loud as the GE VR and you can run a lighter stylus wieght (VTF) than the VRII.
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Thanks Larry, I think I may change my mind and look for another GE VR II instead. It works so well with the RIAA 2 input and I will have stereo playback on RIAA 1 with the Miracord and Shure cart. If anyone has a GE VR II they would be willing to part with please let me know. I would be willing to trade or pay. I need the turning part of the cart as well.

Thanks
 
larryderouin said:
Yeah. As long as the externals are either 8 or 16 ohm, no problem. They are in parallel so the ohm load on the speakers to the unit will drop, but the circuits can handle it.
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So I'm going to order two ceiling speakers to run at the same time as the internal speakers. Is there any way that's more efficient than another to do it? The internal speakers are 18 ohm and I know Rt=R1+R2 so if I add 18 ohm external in paralell I will actually have 9 ohms. Would I be better to use the 8 ohm connection? Or what if I order 4 or 6 ohm externals should they be installed at the perspective terminal and leave the mains on 16? I assume I want to order as an efficient speaker as possible as well.

BTW one of our members is sending me a GE VRII so I'm set for the dual TT setup using RIAA 1 and RIAA2 both with correct loading.
 
The best conventional setup you could do would likely be to use 16 Ohm ceiling speakers ------- if you can find them. A 16 Ohm speaker in parallel with an 18 Ohm speaker will net an impedance of 8.47 Ohms -- or very close to the 8 Ohm tap offering on the amplifier, which is what you would use. Unless you are well versed in impedance formulas and impedance vrs frequency curves for the speakers being used, I would stay well away from using multiple output taps on the amplifier. It can be done, but you really need to be careful so that the overall impedance reflected to the output tubes -- over the whole of the audio range -- remains close to the target value that the transformer was designed to reflect.

Dave
 
I got a little side tracked! My niece fell in love with the Miracord 50H so I had to rebuild one for her. It replace her Audio Technica LP-60. Then I decided to move my main player, Empire 298, to my office with a Fisher X-202-B and FM-200-B tuner. it's a beautiful match! So that left me having to restore another TT to replace it. Anyway I'm back to the Executive now. I ditched the ceiling speaker idea. I did get the Garrard TT installed and it sounds great. While I'm waiting on the caps, for more detailed bass, I'm going to wrap it up and buff the top surface.

My main question now is about the speaker balance. I have to turn it to the right +3 to get balanced sound. What do you suppose is causing this problem and whats the fix?

Thanks!

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If turning the balance control to a +3 favor right setting causes the unit to maintain balance at all volume settings, then there is definitely an issue somewhere in the circuit causing the imbalance. If the setting of the balance control to produce balanced sound varies with the volume control setting, then the volume control itself will be the prime target causing the imbalance. If the problem is circuit related, and you're good with a schematic, then there are simple troubleshooting steps we can talk you through to isolate where the problem is. For now however, you need to verify if the imbalance is present on all inputs (high and low level), or just on the phono inputs (since that is the use mode you've been discussing). If it is phono, be sure that the phono level controls are either turned up full, or adjusted equally if set to some intermediate setting. These controls are small screwdriver adjustment controls located just behind the front panel cover, under the phono preamp tubes. There is also a set of controls for the Aux inputs there as well.

Dave
 
dcgillespie said:
If turning the balance control to a +3 favor right setting causes the unit to maintain balance at all volume settings, then there is definitely an issue somewhere in the circuit causing the imbalance. If the setting of the balance control to produce balanced sound varies with the volume control setting, then the volume control itself will be the prime target causing the imbalance. If the problem is circuit related, and you're good with a schematic, then there are simple troubleshooting steps we can talk you through to isolate where the problem is. For now however, you need to verify if the imbalance is present on all inputs (high and low level), or just on the phono inputs (since that is the use mode you've been discussing). If it is phono, be sure that the phono level controls are either turned up full, or adjusted equally if set to some intermediate setting. These controls are small screwdriver adjustment controls located just behind the front panel cover, under the phono preamp tubes. There is also a set of controls for the Aux inputs there as well.

Dave
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Dave, It's on all inputs, I'm ready for trouble shooting instructions!
 
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