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-   -   Dennis Had Inspire Amps (https://www.audioaficionado.org/showthread.php?t=24170)

Analog Addict 01-05-2021 03:51 PM

Quote:

Originally Posted by AMammal (Post 1028352)
Contacted Dennis about two weeks ago about getting one of the new cj5 preamps and an amp that would power our klipsch forte iii's. I didn't hear back but figure that's because he's so busy filling orders for the cj5. Then I saw this sale and just bought an ebay listing for an lp3-a preamp prototype Deninis made in 2/25/2016 and a 6v6r that Dennis made back in 12/3/2015. It was sold under consignment (i would be the third owner) and I can return in the next 14 days no questions asked. Even though I knew the 6v6r may not have the power we need for the forte iii's (we have a large living room/kitchen space they are in). We figured the pre would be worth it and we could use the 6v6 in a smaller room and get the qmb25 monoblocks or another DH amp he might suggest.

The wife and I were super excited to get them home and listen.

It sounds... Terrible. The vocals have no resonance and are flat and present behind the percussion and with lots of sibilance. The midrange is muffled and MIA. My wife had to leave the room when it's playing because it sounds so bad. And I got quite the headache due to the fatiguing nature. I'm suspicious either the tubes are in the wrong places, are poor matches or just worn out in a way the tube tester did not reveal. (Im a complete noob when it comes to tubes, so not able to tell if these are any good). The only issues with the amp I noticed is that the socket on the lp3-a that holds the RCA 80 tube is loose. (If I turned the lp3-a upside down and patted it with my hand, it's loose enough it would probably fall out). Also, there was some occasional popping and crackle when turning the volume knob manually at first.

I am a new member here and have been reading this thread for the past week or two (on page 128 from the beginning) but have jumped ahead a bit here and there and searched the thread. We had a friends rogue cronus magnum ii hooked up to our system which sounded phenomenal, but wanted to hear /try out the dennis had experience before deciding between a DH, Rogue, or Raven amp /preamp or integrated. Not sure we want to go through the hassle of sending it to Dennis or trying to roll tubes that we would have to order and wait on. We're wondering if there are any options /suggestions you all may have before returning it.

No noticeable plate glow or anything with the tubes.

Here is the tube compliment :

Lp3-a:
RCA 80
3x Russian 6H1Pi
GE 6cG7

6v6'r:
RCA 80
2x Svetlana 6550c (switched back and forth with 2x shu Guang 6v6GT)
Russian 6H1Pi

Sorry to hear your experience has been disappointing. Here are my thoughts...

1) Suspect # 1 - the tubes. Do you have the right compliment of tubes in the right position? Are the tubes weak or not functioning properly? I'm not a fan of modern manufacture tubes, believing the quality is not as good as old US or Euro tubes. Unfortunately, it doesn't sound like you have any immediately available replacements. As far as a Klipsch Forte, I've owned Forte IIs, and IIRC, they are mid 90's as far as db/w/m and a 6V6'er should be able to drive them to well over 100db, so that shouldn't be a problem.

2) Suspect # 2 - Is the amp in the condition that it left the Inspire shop? Hard to tell without pix. As the 3rd owner, it's very possible that some hack has been in it and has messed with DJH's handiwork. I would recommend that you take high rez pix of the pieces from the top with and without tubes, and also flip both unit's over and take off the bottom cover and take some high rez pix of the circuitry. The sharper and clearer the pictures the better. Host them somewhere like Flickr and then post them here.

Between Straitwire and myself we should be able to tell if someone's been in it. Be sure to unplug the units before removing the bottom plate and also take a pic of the bottom plate before unfastening it. If the fasteners are different, well, then you already have your answer....Personally, if you can return them, I would keep that as a last resort. However, buying used equipment is always a gamble if you can't diagnose and repair it yourself. You could always try Dennis again about a new manufacture CJ5 and an amp of your choice on Ebay. I know for a fact he has contacted the fellow on the last page who was looking for him....

AMammal 01-05-2021 04:11 PM

Quote:

Originally Posted by Masterlu (Post 1028354)
In the spirit of trying to help you, I am approving your post. Although, this really isnít the proper venue to correct a poor experience on eBay.

My sincerest apologies and gratitude for allowing the post. I do not want to hijack this thread as it is full of so much good information.

AMammal 01-05-2021 04:24 PM

Quote:

Originally Posted by Analog Addict (Post 1028357)
Sorry to hear your experience has been disappointing. Here are my thoughts...

1) Suspect # 1 - the tubes. Do you have the right compliment of tubes in the right position? Are the tubes weak or not functioning properly? I'm not a fan of modern manufacture tubes, believing the quality is not as good as old US or Euro tubes. Unfortunately, it doesn't sound like you have any immediately available replacements. As far as a Klipsch Forte, I've owned Forte IIs, and IIRC, they are mid 90's as far as db/w/m and a 6V6'er should be able to drive them to well over 100db, so that shouldn't be a problem.

2) Suspect # 2 - Is the amp in the condition that it left the Inspire shop? Hard to tell without pix. As the 3rd owner, it's very possible that some hack has been in it and has messed with DJH's handiwork. I would recommend that you take high rez pix of the pieces from the top with and without tubes, and also flip both unit's over and take off the bottom cover and take some high rez pix of the circuitry. The sharper and clearer the pictures the better. Host them somewhere like Flickr and then post them here.

Between Straitwire and myself we should be able to tell if someone's been in it. Be sure to unplug the units before removing the bottom plate and also take a pic of the bottom plate before unfastening it. If the fasteners are different, well, then you already have your answer....Personally, if you can return them, I would keep that as a last resort. However, buying used equipment is always a gamble if you can't diagnose and repair it yourself. You could always try Dennis again about a new manufacture CJ5 and an amp of your choice on Ebay. I know for a fact he has contacted the fellow on the last page who was looking for him....

I really appreciate you taking the time in responding and I suppose I should have thought about my lack of expertise and ability to troubleshoot prior to buying used and posting since I'm so new to the tube world. The expertise in this thread is mighty hard to resist. I'll post some photos ASAP.

Moderators: If there is a more appropriate place or method to continue this conversation, please let me know. I am extremely nervous about misusing the forum.

bearcity 01-05-2021 05:17 PM

Quote:

Originally Posted by AMammal (Post 1028352)
Contacted Dennis about two weeks ago about getting one of the new cj5 preamps and an amp that would power our klipsch forte iii's. I didn't hear back but figure that's because he's so busy filling orders for the cj5. Then I saw this sale and just bought an ebay listing for an lp3-a preamp prototype Deninis made in 2/25/2016 and a 6v6r that Dennis made back in 12/3/2015. It was sold under consignment (i would be the third owner) and I can return in the next 14 days no questions asked. Even though I knew the 6v6r may not have the power we need for the forte iii's (we have a large living room/kitchen space they are in). We figured the pre would be worth it and we could use the 6v6 in a smaller room and get the qmb25 monoblocks or another DH amp he might suggest.

The wife and I were super excited to get them home and listen.

It sounds... Terrible. The vocals have no resonance and are flat and present behind the percussion and with lots of sibilance. The midrange is muffled and MIA. My wife had to leave the room when it's playing because it sounds so bad. And I got quite the headache due to the fatiguing nature. I'm suspicious either the tubes are in the wrong places, are poor matches or just worn out in a way the tube tester did not reveal. (Im a complete noob when it comes to tubes, so not able to tell if these are any good). The only issues with the amp I noticed is that the socket on the lp3-a that holds the RCA 80 tube is loose. (If I turned the lp3-a upside down and patted it with my hand, it's loose enough it would probably fall out). Also, there was some occasional popping and crackle when turning the volume knob manually at first.

I am a new member here and have been reading this thread for the past week or two (on page 128 from the beginning) but have jumped ahead a bit here and there and searched the thread. We had a friends rogue cronus magnum ii hooked up to our system which sounded phenomenal, but wanted to hear /try out the dennis had experience before deciding between a DH, Rogue, or Raven amp /preamp or integrated. Not sure we want to go through the hassle of sending it to Dennis or trying to roll tubes that we would have to order and wait on. We're wondering if there are any options /suggestions you all may have before returning it.

No noticeable plate glow or anything with the tubes.

Here is the tube compliment :

Lp3-a:
RCA 80
3x Russian 6H1Pi
GE 6cG7

6v6'r:
RCA 80
2x Svetlana 6550c (switched back and forth with 2x shu Guang 6v6GT)
Russian 6H1Pi

Are you sure the 80 rectifier was in correctly? That is a 4 pin tube with 2 pins slightly larger than the others. If the one shipped is the one Dennis originally provided there is a sharpie dot on the pin face of the tube and on the socket which should be aligned. This is the only tube in your Inspires that can be installed incorrectly. In fact Dennis stopped using this tube because owners kept installing them incorrectly. I am not sure what would happen if it was installed incorrectly. Damage or just awful sound, or both. Straitwire or Analog may be able to answer that.

AMammal 01-05-2021 05:35 PM

Quote:

Originally Posted by bearcity (Post 1028370)
Are you sure the 80 rectifier was in correctly? That is a 4 pin tube with 2 pins slightly larger than the others. If the one shipped is the one Dennis originally provided there is a sharpie dot on the pin face of the tube and on the socket which should be aligned. This is the only tube in your Inspires that can be installed incorrectly. In fact Dennis stopped using this tube because owners kept installing them incorrectly. I am not sure what would happen if it was installed incorrectly. Damage or just awful sound, or both. Straitwire or Analog may be able to answer that.

This is a great pickup. Thanks for the reply.

I scrutinized the tubes when first installed, and did notice the 2 larger pins and oriented them correctly. They have been installed with the correct orientation all along.

There is a red dot on the rectifier socket of both units and a sharpie dot on the LP-3a 80 rectifier tube but not on the tube in the 6v6'er.


Thanks again. Photo's posted below: (tubes are in order of how they were placed in amps) I have more photos, these were reduced for the page. Thanks again all.

https://live.staticflickr.com/65535/...991c7746_z.jpg

https://live.staticflickr.com/65535/...1cddb6a8_z.jpg

https://live.staticflickr.com/65535/...19777efa_z.jpg

https://live.staticflickr.com/65535/...e69fa9b0_z.jpg

https://live.staticflickr.com/65535/...578f3129_z.jpg

https://live.staticflickr.com/65535/...fa239bcf_z.jpg

bearcity 01-06-2021 09:48 AM

Quote:

Originally Posted by AMammal (Post 1028374)
This is a great pickup. Thanks for the reply.



I scrutinized the tubes when first installed, and did notice the 2 larger pins and oriented them correctly. They have been installed with the correct orientation all along.



There is a red dot on the rectifier socket of both units and a sharpie dot on the LP-3a 80 rectifier tube but not on the tube in the 6v6'er.





Thanks again. Photo's posted below: (tubes are in order of how they were placed in amps) I have more photos, these were reduced for the page. Thanks again all.



]



Rereading you troubles I have a few diagnostic suggestions. To start since you now are inside go ahead and get that 80 socket tightened up. If you have another preamp or amp try inserting the inspires in one at a time and see if you can detect the problem trending device. If you have a source with an output level control you can go strait to the amp as well. Just turn control down to start. Donít want to send full volume to the speakers on startup.

Since your troubles sound issues donít seem to be channel specific I am guessing power supply issue and therefore rectifier (80) problem. If you can do as above try swapping 80s. Sometimes tubes get damaged during transit. Those 80s are vintage. Havenít been made in many many years. And yes sometimes a tube can be bad and not register that on most tube testers.

Anyway welcome to the Inspire family and to tubes in general. You jumped in with both feet. You might as well swim around for a while. Tubes gear does require a bit more active participation than SS. I have no doubt when you get these Inspires dialed in you will be happy you jumped.

BTW, circuits look clean and orderly like from factory. Others here might see something amiss but I do not at cursory inspection.

Analog Addict 01-06-2021 12:40 PM

I agree with bearcity, although it may help to post a full sized image of the pre amp to flickr in order to be able to fully examine the innards. The amp looks unmolested and I don't see any obvious component failure. Without a tester, here's what I would do with the rectifiers. Obviously, make sure both the pieces have been powered off and let sit for awhile, because you don't want any nasty surprises. Make sure they are unplugged before starting in.

1) Tighten the rectifier socket. This is the white ceramic socket with 4 triangular shaped contacts. I vastly prefer digging up old Amphenol 4 pin sockets for my purposes, but Dennis can't source these and regularly gives me $hit for my old recycled sockets. That being said, IMO the old sockets are made of superior materials and better constructed. Anyway, use a fine needle nose plier and gently squeeze the triangular shaped pin sockets from the underside. They should move closer together and grip the pins better. You should definitely notice a better grip on the tube.

2) Clean the contact surfaces. This can either be done with deoxit sprayed on the pins on one of the tubes and then the tube gently slid in and out of the socket in order to remove any potential oxidation. Another more decisive method of cleaning is to take a small round jewelers file and gently abrade the inside contact surfaces of the pin connectors.

3) Rather than have you test B+ voltages, I would grab pieces of your SS gear and test the pieces individually. Retube the pieces, and hook a SS amp up to the pre amp and listen. Hook a SS preamp up to the amp and listen. Any difference? Switch the rectifiers between the two pieces and listen again. Finally if everything sounds good, hook both Inspire pieces back together again and listen.

See what you come up with....

TheHammsBear 01-07-2021 09:54 PM

Has anyone here run a pair of kt88s vertical bi-amped?

bearcity 01-08-2021 09:17 AM

Quote:

Originally Posted by TheHammsBear (Post 1028559)
Has anyone here run a pair of kt88s vertical bi-amped?



Not vertical. I horizontally bi-amped my Proac DT8s with my PSE on the lows and 6V6er (with volume control) on the highs to great effect. Really made the Proacs come alive. Thought real hard about getting a second PSE and V bi-amping. Could not justify the setup and have since sold the Proacs.

FloridaBoy 01-08-2021 11:27 AM

Quote:

Originally Posted by Analog Addict (Post 1028429)
I agree with bearcity, although it may help to post a full sized image of the pre amp to flickr in order to be able to fully examine the innards. The amp looks unmolested and I don't see any obvious component failure. Without a tester, here's what I would do with the rectifiers. Obviously, make sure both the pieces have been powered off and let sit for awhile, because you don't want any nasty surprises. Make sure they are unplugged before starting in.

1) Tighten the rectifier socket. This is the white ceramic socket with 4 triangular shaped contacts. I vastly prefer digging up old Amphenol 4 pin sockets for my purposes, but Dennis can't source these and regularly gives me $hit for my old recycled sockets. That being said, IMO the old sockets are made of superior materials and better constructed. Anyway, use a fine needle nose plier and gently squeeze the triangular shaped pin sockets from the underside. They should move closer together and grip the pins better. You should definitely notice a better grip on the tube.

2) Clean the contact surfaces. This can either be done with deoxit sprayed on the pins on one of the tubes and then the tube gently slid in and out of the socket in order to remove any potential oxidation. Another more decisive method of cleaning is to take a small round jewelers file and gently abrade the inside contact surfaces of the pin connectors.

3) Rather than have you test B+ voltages, I would grab pieces of your SS gear and test the pieces individually. Retube the pieces, and hook a SS amp up to the pre amp and listen. Hook a SS preamp up to the amp and listen. Any difference? Switch the rectifiers between the two pieces and listen again. Finally if everything sounds good, hook both Inspire pieces back together again and listen.

See what you come up with....

AA the OP is a tube Noob and, IMHO, it may be better to return the gear while he can.


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