BobTFM35

Just about anything can be going on. I assume you have alot of confidence in the repair facility. Have you contacted them for some guidance and or suggestions? I would do one of two things. Work my way backwards removing a component and testing to see if the hum or hissing has gone away. Or unhook everything then add an item one at a time. This is in no particular order, so..... I remember from your previous post you were trying to bi- amp some speakers and at the end you had everything "singing". So things worked then. Something has changed from then to now, is anything new? 1. I would plug the bluos into the CD input and then test. 2. Next I would remove the sub from the bluos then test. 3. I assume the same speakers. What make and model? 4. Was the new non inverting amp tested before and worked fine so we can rule it out for now? Still bi-amping? 5. Tubes were replaced. Who sourced the tubes? What were they? Matched sets and tested? Line board and or phono board tubes? 6. Any other parts replaced on the preamp 7. Any new cables? Just look at one thing at a time and something will pop up.

Welcome to the Carver site!! Should be an interesting pairing. I use a 6cb in one of my systems. What's the candidate for the preamp? As for the music side, records or cd's?

If you don't see what you need in the Manuals and Specsheets section, maybe one of these three offerings on eBay might be of interest. https://www.ebay.com/sch/i.html?_nkw=carver+klw+audio+service+manual&_sacat=293&_from=R40&_trksid=m570.l1313&_odkw=carver+klw+service+manual&_osacat=293

Welcome to the Carver site!!

Welcome to the Carver Site!! Tell us a little bit more about the system using the PM175.

Welcome to the Carver Site!!

https://www.turntableneedles.com/round_rubber_drive_belt_medium

@MattB @gwolford A few places I have in my saved folder, Listed in no particular order https://lptunes.com/collections/vpi-turntable-belts https://www.lpgear.com/category/V1.html https://www.turntableneedles.com/Rubber_Drive_Belts-Tape_Decks_Turntables Was able to source a tt belt from Amazon based on knowing the size and cross section information. For mine I used this to start the search; Turntable Belt for Record Player 20.7" Replacement Flat Medium

Welcome back!!

Welcome to the Carver site!!

Welcome to the Carver Site!! Tell us more about yourself and your equipment. Download the file in this link to find belt size information. And for good measure look at this

Welcome to the Carver site!! I previously owned a IV. Question, Is the unit still operational and not experiencing any problems, and you just want to get it refreshed due to age? Or it is experiencing problems? At one time I owned a IV and it gave me many years of GREAT pleasure. I had a recap done and the unit completely went dead after one year. Nothing related to the recap just the processor failure it was determined. I really loved the unit but not enough to try fixing it again nor purchase another replacement. I put that money into a new Marantz AV unit that had a 5 year warranty. Its not exactly the same, but I have improved several items around it that more than makes up for the loss of the Sunfire. I also was able to incorporate all my older Carver equipment and add new modern day equipment so it was, for me, a big plus.

Welcome to the Carver site!!

Welcome to the Carver site!! Tell us what's in your collection.

I will also go along with @Sk1Bum for the C-4000t because of the addition of the Digital Time Lens function.

I would go with this preamp, Its a Carver C-4000, it looks smart and classic old school. It is available here, last one in the list, https://soundsclassic.com/preamps.html Next one after that would possibly be either a c-1, c-11 or c-16 Tuners as suggested by @Sk1Bum

take a very close look and I mean a very close look at the RCA connection points for the tape input and output and for the pre outs for the front. For me they look broken as the outer shell is missing.

Are the pictures that you posted are they of the unit you are thinking of purchasing?

They are different because what is shown is a CT-26v. What I show is a picture that represents the model you mentioned in your post, a CT-23.

@Scott Andrew On the back of the 23 you use the audio out to go to the input of the amp.

Welcome to the Carver Site!! Looks like the CT-23 is a nice fit for your two-channel setup. Make sure that it has the remote. If you are thinking of a system beyond a two-channel, say a surround sound configuration then maybe something like the CT-26V or the CT-29v (with the remotes) will be good to start off with. With those two units you can add amps for a center channel, surround and a sub as your system grows. For your 420 amp, you will need to get or make an interconnect cable that goes from an RCA to 1/4" phone jack. The 420s were sold in a US configuration and an export configuration and either configuration accepts balanced and unbalanced inputs. The manual covers this. Again Welcome.

Welcome to the Carver site!! @TomSens 6 likes and advanced to Novice!!, you are now able to upload some pics in a topic of your system(s) in the Members Systems area.

@Ultramafic1 That will be a fantastic build on the amp and a great combination with the C-1 if I may say so. Why, my son has a PL 400 paired with a C-1 in his B system. I think you are going to like it.

Welcome to the Carver site!! What type of amp are you having built? I like your idea of using separate components because in this way you have versatility. There are so many options that you can choose for a Carver Preamp. You have units like the C-1 up to the C-19 that are excellent performers. My system is built on using seperates. Two preamps, the C-4000 and 4000t, are units that have some special features that I particularly like. My son purchased a C-4000 and after it was restored, I used it for an extended period of time in my system to break it in. Each of them have unique features such as Peak Unlimiter, Auto Correlator noise reduction system, and its Time Delay and Sonic Hologram Generator. You can also look at the HR and the CT line and choose a model that incorporates pre outs into their design. This way you can introduce more amps into your system as it grows. These have remotes with volume control function. The C series can be retrofitted with remote volume control. The C-19 is a tube preamp if that is of interest. Here is a reference for a place that specializes in restorations and upgrades. Greg is a member here. "Choosing Nelion Audio means more than selecting a repair shop; it signifies embracing an ethos that values your musical enjoyment and the longevity of your hard-earned gear. We are prepared to guide you through the world of high-fidelity audio, ensuring worry-free experiences with vintage equipment. Join us on this journey as we explore and create new and exciting audio adventures together. We are here for you!" Services - Nelion Audio

@sparda236 If I may offer a suggestion to possibly get better exposure for your question. I would create/start a new topic/post in this area, https://thecarversite.com/forum/137-sunfire-speakers/ @Sk1Bum